Homo Biologicus: An Evolutionary Model for the Human Sciences [1 ed.] 9783428477494, 9783428077496

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CHARLES ELWORTHY · Homo Biologicus

Sozialwissenschaftliche Schriften Heft 25

Homo Biologicus An Evolutionary Model for the Human Seiences

By

Charles Elworthy

Duncker & Humblot · Berlin

Die Deutsche Bibliothek - CIP-Einheitsaufnahme

Elworthy, Charles:

Homo biologicus : an evolutionary model for the human sciences I by Charles Elworthy.Berlin : Duncker und Humblot, 1993 (Sozialwissenschaftliche Schriften ; H. 25) Zugl.: Berlin, Freie Univ., Diss., 1991 ISBN 3-428-07749-0 NE:GT

D 188 Alle Rechte vorbehalten © 1993 Duncker & Humblot GmbH, Berlin Fotoprint: Berliner Buchdruckerei Union GmbH, Berlin Printed in Germany ISSN 0935-4808 ISBN 3-428-07749-0

To my family

Preface The following work provides a framework through which human characteristics can be understood, and human behaviour modelled. Its principal impetus arose from the dilemma in which I found myself, having accepted a maximising model of man as a result of reading economics in England, and a maximising model of state behaviour through studying international relations in the United States. I became convinced that there was no trivial solution to the incompatibility between egoistic individuals and unitary states, and that a realistic study of human behaviour required a foundation in the natural sciences, specifically evolutionary theory. This belief was reinforced through my experience of the recent upheavals in central Europe, where the inadequacies of conventional models in the social sciences became very apparent. The book is a revised and extended version of my doctoral dissertation for the Otto Suhr Institute of the Free University of Berlin. The generalliterature review extends until works appearing before mid 1991, with a more limited examination of more recent publications. The principal argurnents and general structure are outlined in the introductory chapter; suffice to note here that it draws on theoretical and empirical work by a !arge number of authors from a variety of fields. The airn is to present certain arguments and provide references to related literature, rather than to test new hypotheses or to report empirical research. Associated with this objective is the extensive use of footnotes and the frequency of quotations. The current fashion in English-language academic publishing is away from such scholarly apparatus, and towards an apparently less intimidating forrnat. There are good reasons for considering such a traditional style more rather than less 'readerfriendly', however, once the reader is accustomed to the appearance. The placement of footnotes at the bottom of the page allows a reader-directed Ievel of inquiry: with a practised eye those who arenot interested in the notes can pass them by, those who wish to read them have only to Iook at the bottarn of the page rather than in endnotes or a bibliography, and those who are not sure can quickly scan them. Notes allow a more sophisticated handling of references than the author (date) system, where qualifications, amplifications, and other remarks must occur in the main text. Given a choice between footnotes and endnotes, it seems more logical to ease the reader's access to them, rather than enforcing a 'finger at the back' form of readership. Similar arguments apply to quotations, especially for a work which so relies on other writers' arguments and research. Firstly, it is simply more intellectually honest. Secondly, the original authors are specialists in their own fields, and can be expected to have crafted their Statements so as to accurately convey their ideas, while an unskilled

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Preface

reconstruction can easily omit or misrepresent important but subtle points. Finally, the discussion often refers to specific arguments by particular authors. Within the "invisible college" associated with a particular subject a simple citation may be appropriate, because all know the original text, but the scope of this work is such that I cannot presume that readers will be familiar with all of the literature cited, and I expect that most would require more than their standard institute or departmentallibrary should they wish to trace the original quotations. The book is intended to be read from beginning to end, as each chapter is based upon its predecessor, and even apparently standard themes are often handled in an unorthodox fashion. For those who wish to refer to a particular author or subject, appropriate indexes are to be found before the bibliography. The glossary contains a list of the principal technical terms as an aid to non-specialist readers. With respect to conventions, double quotation marks have generally been used when refering to the word or expression as such, or when the text has been defined by somebody eise. Single quotation marks have normally been reserved for occasions when I have wished to apply an expression in a non-standard sense, or to use an informal word or phrase. Personal pronouns have been avoided as far as possible, but standard usage has been followed in the use of "he" with the implicit meaning of "he and [or] she" when necessary. The style generally follows that recommended in the Chicago Manual of Style and by Turabian,l except fortheusage of square brackets [... ] for frrst editions, and the delirnitation of the details and page numbers of reprints with parantheses {... }.

1 University of Chicago Press, The Chicago Manual of Style [1906]13th ed. rev. and expanded (Chicago: University of Chicago Press, 1982); Kate L. Turabian, A Manual for Writers of Term Papers, Theses, and Dissenations [1937] 5th ed. rev. and expanded by Bonnie Birtwistle Honigsblum (Chicago: University of Chicago Press, 1987).

Acknowledgements I would like to thank Professor Dr. Dr. Hans-Joachim Menge! LL.M. (Yale) for acting as my Doktorvater and making this work possible, and the members of my doctoral examination committee. Although fortunate in terms of world events and the freedom offered to doctoral students, the choice of Berlin posed particular problems for interdisciplinary research in fields where the majority of Iiterature is published in English. A !arge number of librarians assisted the project, and I thank collectively: the staff of the Berlin state library where the bulk of the research was conducted; the central and subsidiary libraries of the Free University and Technical University of Berlin; the British library; and the Cambridge, Yale, Stanford, and Otago University libraries. One of the cultural differences between continental Europe and the English-speaking world is that academic titles are part of the legal name in the former, but are often omitted in the latter, and I apologise if I use an incorrect form in acknowledging my thanks. Many benefactors assisted my research by offering advice, providing publications, and giving permission for the reproduction of illustrations, and I express my gratitude to: Professor Richard Alexander, Professor Robert Axelrod, Professor David Buss, Professor Robert Carneiro, Professor Leda Cosmides, Professor Martin Daly, Dr. Richard Dawkins, Professor Riley Dunlap, Dr. Margaret Gruter, J.S.M., participants in the Human Behaviour and Evolution conferences, Dr. Deborah Larson, Mr Hamish McHardy, Professor Anne McGuire, Ms. Frances Michelmore, Mrs Alexandra Milgram, Dr. Geoffrey Miller, Professor Dr. K.-D. Opp, Dr. Roger Pearson, Professor Leopold Pospi§il, Professor John Tooby, Professor Nancy Thornhill, Professor Randy Thornhill, Dr. Robert Rosen, Professor James Rosenau, Professor J. Phillippe Rushton, Professor Bruce Russett, Professor Dr. Reinhard Selten, Professor Robert Shiller, Dr. Pouwel Slurink, Dr. Chris Stringer, Professor Margo Wilson, and Professor David Sloan Wilson. A number of arguments have been refined through discussions with students in my evolution seminars, and I thank them for their openness and enthusiasm. For helping to prepare the manuscript for publication I would li.ke to express my appreciation to Professor Dr. Peter Häberle, Frau Stefanie Lorenzen, Ms. Hannah Pearce, Shpal Bay Press, Dr. John Small, Mr. Timothy Smith, Frau Moni.ka Wohnsiedler, and nro anonymous referees. I am grateful to Mr. Michael Robilliard who extracted the essendals from my duttered sketches, and drew the figures 3.1-3.5 and 5.1. Finally I am thankful to Professor Norbert Sirnon of Duncker & Humblot for offering to publish the book in English, and to Frau Barbara Burmeister for her advice and assistance in preparing the manuscript.

Contents I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Il. The Elements of Evolution . . . . . . . . . . . . I. Hierarchies and Reductionism . . . . . . . . 2. Elements of the Evolutionary Process . . . a) lnheritance, Replicators, and Vehicles . b) Variation . . . . . . . . . . . . . . . . . . . . . c) Selection . . . . . . . . . . . . . . . . . . . . . d) Genetic Drift . . . . . . . . . . . . . . . . . . e) Isolation and Specialion . . . . . . . . . . 3. Levels of Selection . . . . . . . . . . . . . . . . a) Genets . . . . . . . . . . . . . . . . . . . . . . b) Kin-Groups . . . . . . . . . . . . . . . . . . . c) Groups . . . . . . . . . . . . . . . . . . . . . . 4. Other Replicators and Vehicles . . . . . . .

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ill. Adaptations and their Characteristics . . . . . . I. The Meaning of Adaptation . . . . . . . . . . . 2. Adaptations from Four Perspectives . . . . . a) Phylogeny . . . . . . . . . . . . . . . . . . . . . b) Function . . . . . . . . . . . . . . . . . . . . . . c) Mechanism . . . . . . . . . . . . . . . . . . . . d) Ontogeny . . . . . . . . . . . . . . . . . . . . . 3. Analysing Adaptations . . . . . . . . . . . . . . a) Maxirnisation Subject to Constraints . . . b) Optirnisation and Maxirnisation . . . . . . c) The Manifestation of Adaptations . . . . .

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IV. Evolution and the Human Psyche . . . . . . . . . . . . . . I. The Cognitive Level and Evolutionary Psychology . 2. Investigating the Cognitive Level . . . . . . . . . . . . . a) The Environment of Evolutionary Adaptedness . b) Cognitive Programs and Computational Theories c) Darwinian Algorithms . . . . . . . . . . . . . . . . . . . d) Ontogeny and Behaviour . . . . . . . . . . . . . . . . .

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Contents 3. Evolutionary Psychology and the Wason Selection Task a) Content Effects on the Wason Selection Task . . . . . b) A Computational Analysis of Social Exchange . . . . c) The "Look for Cheaters" Darwinian Algorithm . . . . 4. Accounting for Hominid Cognitive Development . . . . . a) Encephalisation . . . . . . . . . . . . . . . . . . . . . . . . . . b) The Capacity for Sociality . . . . . . . . . . . . . . . . . . c) The "Balance of Power" Hypothesis

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V. From Psychology to Behaviour . ...... . .. . . . ..... .. . ..... . . .. . . 1. Genet Maximisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a) Specification of Somatic Maximisation . . . . . . . . . . . . . . . . . . . . . . . b) Habitat Selection .... . . . ......... . . ... ............ . . . . . c) Responses to Hazards and Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . d) Avoidance of Unprofitable Investment . . . . . . . . . . . . . . . . . . . . . . . 2. K.in-Group Maximisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a) Specification of K.in-Group Maximisation . . . . . . . . . . . . . . . . . . . . . b) Sexual Preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c) Male Reproductive Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Group Maximisation . .. ................ . .. .. . ... .. ..... ... a) Specification of Group Maximisation . . . . . . . . . . . . . . . . . . . . . . . . b) Obedience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c) Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . d) Obedience and Conformity as Community Effort . .... . ..... . .... 4. Aggregate Maximisation and Non-Optimality .... .. ............ .. .

113 113 113 118 121 127 133 133 137 139 146 146 149 153 157 165

VI. Homo Biologicus and Human Characteristics . . . . . . ... . ...... . ... . . 1. Characterising Homo Biologicus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Homo Biologicus versus Homo Oeconomicus . . . . . . . . . . . . . . . . . . . . a) Choice under Uncertainty ....... . .. . ... . . .......... . . . . .. b) Excess Volatility in Securities Markets .. .. . ... .... . ....... . .. c) Household Behaviour and Family Altruism . .. . ...... . ... . .. . .. d) War . . ........ ... .. . . . .... ..... . .. . .. . .... .. ... ... . 3. Linking the Human Seiences ... . ... .. . .. . .. . ... . . ..... .... .. 4. Evolutionary Research and Human Characteristics ... . . ... . . . . . . ... a) Opposition to Evolutionary Research . . .. . . .. .. . .. . .... . .. . .. b) Consequences of "Biophobia" .. . .... . . . ........ . .. . . . . . . . . c) Diversity and Discrimination .......... . .. . ....... . ... ... .. d) Determinism and Freedom .... . ........ .. .. . .. . .. . . . . . . ..

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VII. Summary and lmplications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

Contents

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Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 Selected Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

Illustrations Figure 3.1 Adaptations from Four Perspectives . . . . . . . . . . . . . . . . . . . . . . . Figure 3.2 The Biological Transformation Locus and the Fitness lndifference Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 3.3 Productivity below the Transformation Locus . . . . . . . . . . . . . . . . Figure 3.4 Functionality below the Fitness lndifference Curve . . . . . . . . . . . . . Figure 3.5 Biological Trade and Expropriation . . . . . . . . . . . . . . . . . . . . . . . Figure 4.1 Wason Selection Task Abstract Problem . . . . . . . . . . . . . . . . . . . . Figure 4.2 Wason Selection Task DrinkingAge Problem . . . . . . . . . . . . . . . . Figure 4 .3 Structure of Social Contract Problems . . . . . . . . . . . . . . . . . . . . . . Figure 4 .4 Allametrie Relationships between Brain and Body Weights for 309 Extant Placental Mamma! Species . . . . . . . . . . . . . . . . . . . . . Figure 4.5 Log Endocranial Valurne Against Actual or Estimated Geological Age for Fossil and Living Hominids . . . . . . . . . . . . . . . Figure 5.1 Levels of Effort over a Hypothetical Human Lifetime . . . . . . . . . . . Figure 5.2 Age-Specific Rates of Homicide Victimization by (A) Genetic Parents or (B) Stepparents . .. . ........... . . . .. . Figure 5.3 Genetic Relationships with Putative Offspring . . . . . . . . . . . . . . . . Figure 5.4 Percent Rape Victims and Percent Fernales in the Population in Relation to Fernale Age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 5.5 Location of Participants in the Initial Obedience Experiment . . . . . . Figure 5.6 Mean Shock LevelsinGroup Pressure Experiment ...... . .. . .. . Figure 6. 1 Real Stock Prices and their Perfeet Foresight Counterparts 1871 to 1986 . . . .. .. . ...... . ...... . ......... . . . ... . .

42 55 58 59 70 84 85 89 96 99 119 133 141 145 150 155 191

I. Introduction Homo biologicus is a model of human characteristics that is proposed as an interface between the natural and the social sciences. I hope that it will serve as a type of market, and allow the linking of what I perceive to be unmatched supply and demand. In evolutionary theory and evolutionary psychology there exists a powerful methodology for explaining human characteristics, but there is a need for sophisticated predictive models of behaviour. In the social sciences there is an enormaus supply of both techniques for analysing behaviour, and data describing it, but a requirement for satisfactory specifications of individual characteristics. Homo biologicus provides a method of uniting these two theoretical worlds, in that its specification is a product of the evolutionary sciences, whereas its application is in the social sciences. The expression "Homo biologicus", with its allusions to species and to biology on the one side, and to "Homo oeconomicus" and "Homo sociologicus" on the other, is intended to emphasise this connection. A further aspect of this role as an interface is that of an evolutionary model for the human sciences, as the model itself is capable of evolving in response to both its natural science and its social science environments. Rather than adopting an inductive methodology - observing human behaviour and working backwards to a model of man - the approach is instead deductive, interpreting the behaviour of humans within the same analytical framework as that used for other species. The development of the argument can be viewed as an example of "hierarchical reductionism", a mode of analysis discussed in the first section of Chapter II, where the higher and more specific Ievels are explained in terms of the lower and more general ones. The study of human characteristics and behaviour - the human sciences - is thus seen as a particular application of generally valid findings from the natural sciences. The book itself is structured in the inverse order of this hierarchy of Ievels, in the spirit of deductive logic. Chapter II considers the essential characteristics of the evolutionary process which gave rise to life, interpreting organisms as the mechanisms through which genetic replicators (genes) influence the world about them in order to survive. 1 Elworthy

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Introduction

Chapter III examines the further implications of this replicator/vehicle view, analysing adaptations as elements in a hierarchy of function and mechanism. The highest element is the survival of the genetic replicators, while the mechanisms by which this is achieved are the vehicles, which then provide functional objectives for their mechanisms, and so on. A central conclusion of this chapter is that each of these Ievels of an adaptation can be assumed to be maxirnising, allowing a strong linkage to neoclassical econornic theory. Chapter IV advances the proposition that the most appropriate way to apply an evolutionary approach to behaviour is to study the psychological mechanisms that underlie it. After an introduction to the methodology of evolutionary psychology, its power is demonstrated in the resolution of the content-effect anomalies in the Wason selection task. The chapter finishes with a consideration of the selection pressures that shaped the comparatively large human brain. Chapter V links tagether the previous chapters and applies them to the analysis of individual behaviour, and derives equations for maxirnisation in terms of each of the relevant vehicles. These theoretical discussions are supplemented by reviews of research indicating the existence of psychological processes instantiating such maxirnisation, and a concluding section which links each of the Ievels together. Having developed a methodology for understanding human characteristics, chapter VI addresses the difficulty of creating predictive models of behaviour. In the first section Homo biologicus is presented as the appropriate interface between the complex and ex post descriptions produced by evolutionary psychology, and the requirement for generaland operational models in the social sciences. This is followed by an investigation of particular forms of behaviour for which Homo oeconornicus provides inadequate explanations, but which are explicable within the Homo biologicus framework. The final sections examine how Homo biologicus could serve as a basis for the linkage of the human sciences, and consider some of the broader issues associated with the approach.

II. Tbe Elements of Evolution 1. Hierarchies and Reductionism

Life is the most complex phenomenon in the known universe, if complexity is conceived as existing when "complicated things have some quality, specifiable in advance, that is highly unlikely to have been acquired by random chance alone". 1 Sirnon has demonstrated that hierarchy is a fundamental principle of "the architecture of complexity"2 and it is thus to be expected throughout the organisation of life. Simon's dassie argumentwas made using a parable oftwo watchmakers, Hora who created subassemblies which were stable when he was interrupted, and Tempus whose watches fell apart and had to be completely reassembled if he was called away. Sirnon demonstrates that the former process is far more likely to be successful than the latter, and concludes that complex entities will generally use hierarchies to simplify their structures. Additional grounds such as "local administration", and "redundancy reduction" ,3 reinforce the importance of hierarchy as an organising principle. The only adequate scientific explanation of the nature of life is the theory of evolution,4 first proposed independently by Darwin and Wallace,5 which posits

1 Richard Dawkins, The Blind Watchmaker (Harlow, Essex: Longman Scientific and Technical, 1986) [hereafter Dawkins, Blind Watchmaker], p. 9. Fora discussion of the meaning of complex.ity with respect to living things see ibid., pp. 6-8. 2 Herben A. Simon, 'The Architecture of Complexity' Proceedings of the American Philosophical Society 106 (December 1962): 467-482 (reprinted in Herben A. Sirnon The Seiences of the Anijicial [1969] 2nd ed. 1981, pp. 193-229 (Cambridge, MA: MIT Press)}, pp. {200-205} [hereafter Simon, 'The Architecture of Complexity']. 3 See e.g., Richard Dawkins, 'Hierarchical Organisation: A Candidate Principle for Ethology' in P. Patrick G. Bateson and Robert A. Hinde (eds.), Growing Points in Ethology, pp. 7-54 (Cambridge: Cambridge University Press, 1976), pp. 16-19 [hereafter Dawkins, 'Hierarchical Organisation']; Keith Nelson, 'Does the Holistic Study of Behavior have a Future?' Perspectives in Ethology (1973): 281-328, esp. pp. 311-317 [hereafter Nelson, 'Holistic Study']; Stanley N. Sahhe, Evolving Hierachical Systems: Their Structure and Representation (New York: Columbia University Press, 1985). 4 Darwin hirnself did not use the term "evolution" in the early editions of the Ortgin of Species, making instead extensive use of the term "natural selection", and later "the survival of the fittest"; see Roben L. Cameiro, 'Introduction' in Roben L. Cameiro (ed.), The Evolution of Society:

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II. The Elements of Evolution

that all species result from incremental changes to previous forms through the operation of natural selection. It is the combination of evolutionary theory with the concept of particulate inheritance, discovered by Mendel,6 that forms the core of modern evolutionary theory. 7 Of the many instances of hierarchies to be found both within nature and in explanations of it, three are central to the structure of this work. The first is the disciplinary hierarchy of evolutionary biology, evolutionary psychology, and the study of behaviour that structures this entire book. The second is the distinction introduced by Dawkins between genetic replicators or genes, the units that life is 'for', and the vehicles that carry them through space and time. The third is the physical "hierarchy of life", whereby biochemical processes result in cells and their elements; which provide the building blocks for physiological processes; which in turn create musdes and hormones; and so on through to behaviour. These traits are produced by the elements of evolution discussed in the next section, and are interpreted as being a hierarchy of mechanisms 'for' vehicles, and ultimately 'for' replicators.

Selections from Herbert Spencer's Principles of Sociology (Chicago: University of Chicago Press, 1967), p. xviii. Unfortunately "evolution" and "evolutionary" are often used in a non-biological sense, especially in the social sciences. Given its widespread acceptance and appropriateness, however, "evolution" will be used in its biological sense in this exposition. 'The firstformal presentation of the theory was by Darwin and Wallace (Charles Darwin and Alfred R. Wallace, 'On the Tendency of Species to Form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection' Journal of the Proceedings of the Linnean Society (Zoology) 3 (1859): 45-63). The classic articulation of the theory is that by Darwin (Charles Darwin, On the Origin of Species by Means of Natural Selection: Or the Preservation of Favoured Races in the Struggle for Life, facsirnile of the Ist ed. of 1859, intro. by Ernst Mayr (Carnbridge, MA: Harvard University Press, 1964) [hereafter Darwin, Origin of Species]). For an account of the development of the theory and methodology used see e.g. Michael T. Ghiselin, The Triumph of the Darwinian Method [ 1969] (Chicago: University of Chicago Press, 1984), passim [hereafter Ghiselin, Triumph of Darwinian Method]. 6 An accessible treatment of the processes of Mendelian genetics and the history of the convergence of evolutionary theory and genetics is provided in Martin Daly and Margo Wilson, Sex, Evolution, and Behavior, [1978], 2nd ed. (Boston: PWS Publishers, 1983), pp. 2-14 [hereafter Daly and Wilson, Sex, Evolution, and Behavior]. 7 Some readers may have gained the impression that alternatives to Darwinian theory, or major revisions of it, are necessary to adequately explain life's structure and form. Even if notasextreme as creationism, proponents of punctuationism, neutralism, cladism, Larnarckianism, molecular drive, and mutationism among others have claimed to show the failure or lirnitations of conventional evolutionary theory. Those interested in an erninently readable interpretation and refutation of these criticisms, in terms of orthodox Darwinism, are recomrnended the relevant sections of Dawkins, Blind Watchmaker, esp. pp. 223-252, 282-318.

1. Hierarchies and Reductionism

5

This creation of an interpretive framework founded on hierarchies clearly involves reductionism: the explanation of one Ievel by 'reduction' to the Ievel below it. Reductionism is an unfashionable methodology in the social sciences in general, and in biological approaches to human behaviour in particular, with reductionists being alleged, for example, to: argue that the properties of a human society are . . . no more than the sums of the individual behaviors and tendencies of the individual humans of which that society is composed. Societies are 'aggressive' because the individuals who compose them are 'aggressive,' for instance.8

Because of such forms of rnisunderstanding it is useful to briefly consider this immensely powerful scientific principle, which: explains a complex entity at any particular Ievel in the hierarchy of organisation, in terms of entities only one Ievel down the hierarchy; entities which, themselves, are likely to be complex enough to need further reducing to their own component parts, and so on.9

An example of such "hierarchical reductionism" could be, for example, the explanation of the operation of a computer to a potential user wishing to type a Ietter. The highest Ievel is that of the word-processing program, which is created through the operation of electronic units such as the central processing unit or the random access memory. These components make use of the serniconducting properties of substances such as silicon, which result in turn from their chemical and physical characteristics, and so forth. For the novice user the first Ievel would probably provide a sufficient explanation, while the designer of a computer would need to go deeper, and the designer of a silicon chip deeper still in the hierarchy. 10 From this perspective reductionism is neither inherently dangerous nor misleading, but rather an immensely powerful scientific technique that has been applied with success to a wide variety of organic and inorganic phenomena. A fundamental rnisunderstanding of reductionism is to interpret it as applying the laws and characteristics of the lower Ievels to those above, as in the ascription of societal aggressiveness to individuals, as quoted above. The

' Steven Rose, Richard C. Lewontin, and Leon J. Kamin, Not in our Genes: Biology, Ideology, and Human Nature (Hannondsworth, Middlesex: Penguin, 1984), p. 5 [hereafter Rose, Lewontin, and Kamin, Not in our Genes]. 9 Dawkins, Blind Watchmaker, p. 13. reductionism" (ibid.). 10

Dawkins tenns this general process "hierarchical

Dawkins develops a similar argument with respect to cars; see ibid. p. 12.

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II. The Elements of Evolution

fallacy of this conclusion is clearly exposed when it is realised that higher Ievels regularly 'escape' the Iirnitations of the Iower Ievels, as in flight, for exarnple, where the higher-Ievel laws of aerodynarnics 'overcome' the physical laws of gravity. The methods by which human psychology and behaviour 'escape' the Iimitations of their Iower Ievels will be discussed in later chapters, but they rest on the results of the evolutionary processes which provide the themes for the following sections.

2. Elements of the Evolutionary Process a) lnheritance, Replicators, and Vehicles

Replicators as defined by Dawk.ins are a very general category, being "anything in the world of which copies are made". 11 Of particular concern to evolutionary theory are particular sub-categories: A genn-line replicator, as distinct frorn a dead-end replicator, is the potential ancestor of an indefinitely long line of descendent replicators. Thus DNA in a zygote is a genn-line replicator, while DNA in a liver cell is a dead-end replicator. Cutting across this classification, an active, as distinct frorn a passive, replicator is a replicator that has sorne causal influence on its own probability of being propagated. Thus a gene that has phenotypic expression is an active replicator.... Special interest anaches to active genn-line replicators, since adaptations 'for' their preservation are expected to fill the world and to characterise living organisrns. Autornatically, those active genn-line replicators whose phenotypic effects happen to enhance their own survival and propagation will be the ones that survive. 12

It is these active germ-line replicators that form the particles of inheritance of evolutionary theory, and which are generally termed genetic replicators in this book. 13

11 Richard Dawkins, The Extended Phenotype: The Gene as the Unit of Selection (Oxford and San Francisco: Freeman, 1982), p. 83 [hereafter Dawkins Extended Phenotype].

12 Richard Dawkins, 'Replicators and Vehicles' in King's College Sociobiology Group (eds.), Current Problems in Sociobiology, pp. 45-64 (Cambridge: Cambridge University Press, 1982), pp. 46-47 [emphasis in the original, hereafter Dawkins, 'Replicators and Vehicles'].

13 This perception of evolution as being 'for' genetic replicators rather than other Ievels or types of entity is closely associated with Dawkins' "selfish gene" presentation of evolutionary theory (Richard Dawkins, The Selfish Gene, [1976], new ed. (Oxford: Oxford University Press, 1989) [hereafter Dawkins, Selfish Gene]). Dawkins has since argued that the complexity of the physical characterisation of genes means that a functional specification is more appropriate for evolutionary

2. Elements of the Evolutionary Process

7

The earth was probably fonned between four and five billion years ago, 14 and there is evidence that the first bacteria emerged approximately one billion years later. 15 Although the processes that generated life are still unclear, they are highly unlikely to have been initially based on DNA molecules, but rather on simpler replicating structures. 16 Successful replicators embody the principles "Longevity, Fecundity, Fidelity", 17 and over time genetic replicators based on DNA have become the basis of living fonns. As active genn-line replicators they are potentially immortal, 18 in cantrast to the finite Jives of phenotypes, the visible fonns of life they create. With advances in molecular and cell biology, so the definition of the units of inheritance has become more complex, so that tennssuch as "muton", "recon", "cistron", "exon", and "intron" have been coined to refine the concept of a gene and to define particular genetic entities. The advantage of the tenn "genetic replicator" isthat it abstracts from these definitional problems, and focuses instead on functional qualities: "a gene

theory, and the term "genetic replicator" is the term that he suggests and that is generally used here; see Dawkins, Extended Phenotype, esp. pp. 81-96. 14 Lynn Margulis, Origin of Eukaryotic Cells: Evidence and Research Implications for a Theory of the Origin and Evolution of Microbial, Plant, and Anima/ Cells on the Precambrian Earth (New Haven, CT: Yale University Press, I 970), p. 46 [hereafter Margulis, Origin of Eukaryotic Cells]. The billions used in the text are American, i.e., 1000,000,000 or 109, as compared to the English billion of 1000,000,000,000 or 10 12•

1s Lynn Margulis, Symbiosis in Cell Evolution: Life and its Environment on the Early Earth (San Francisco: W.H. Freeman, 1981), p. 7 [hereafter Margulis, Symbiosis in Cell Evolution]. 16 For a review of experiments in molecular replication see Leslie E. Orgel, 'Molecular Replication' Nature 358(6383) (16 July 1992): 203-209; Stephen F. Mason, Chemical Evolution: Origin of the Elements, Molecules, and Living Systems (Oxford: Clarendon Press, 1992), esp. pp. 232-259; Laurence D. Hurst and Richard Dawkins, 'Evolutionary Chemistry: Life in a Test Tube' Nature 357(6375) (21 May 1992): 198-199. A popular hypothesis isthat the first replicators were molecules or associations of molecules that emerged in the "primeval soup"; see e.g., Richard C. Lewontin, 'The Units of Selection' Annual Review of Ecology and Systematics I (1970): 1-18, at pp. 2-3 [hereafter Lewontin, 'Units of Selection'). A summary of experiments which have succeeded in producing many of these macromolecules from inorganic matter in Iabaratory experiments is provided in Margulis, Symbiosis in Cell Evolution, pp. 75-85, sumrnarised in Table 4-8 pp. 80-85.

17 Richard Dawkins, 'Replicator Selection and the Extended Phenotype' Zeitschrift für Tierpsychologie 47 (1978): 61-76, at p. 68 [hereafter Dawkins, 'Replicator Selection']. See also Dawkins, Extended Phenotype, p. 184.

11 "Genes are potentially immortal, in the sense of there being no physiological Iimit to their survival, because of their potentially reproducing fast enough to compensate for their destruction by external agents." George C. Williarns, Adaptation and Natural Selection: A Critique of Some Cu"ent Evolutionary Thought (Princeton, NJ: Princeton University Press, 1966), at p. 24 [hereafter Williams, Adaptation and Natural Selection].

8

II. The Elements of Evolution

is defined as any portion of chromosomal material that potentially lasts for enough generations to serve as a unit of natural selection". 19 The inheritance of characteristics by genetic replicators, as they pass from phenotype to phenotype, provides the foundation of the evolutionary process. They provide strands of continuiiy, occasionally modified by mutation, through evolutionary time. An example is provided by the histone H4 gene, which has been replicated some tens of billions of times over the last several billion years and which, by influencing the formation of chromosomes, plays an important role in both animals and plants.20 The process of evolution from this genic perspective is based upon the differential survival of genetic replicators, due to the effect of selection on the vehicles in which they exist.21 There are various categories of vehicle associated with the Ievels of the hierarchy of life, including cells, individuals, social groups, and species: Chromosomes and cells are gene vehicles within organisms. In many species, organisms arenot dispersed randomly but go around in groups. Multi-species groups form comrnunities or ecosystems. At any of these Ievels the concept of vehicle is potentially applicable. Vehicle selection is the differential success of vehicles in propagating the replicators that ride inside them. In theory selection may occur at any Ievel of the hierarchy.Z2

A vehicle is thus a generalisation of the idea of a phenotype, in the same way that an active germ-line replicator is a generalisation of the idea of a gene. In both cases the emphasis is on the nature and function of the entities, rather than their physical manifestation.

19 Dawkins, Sel.fish Gene, p. 28. Dawkins acknowledges deriving this frorn the more technical definitions in Williams, Adaptation and Natural Selection: "I use the term gene to mean 'that unit which segregates and recornbines with appreciable frequency'", and "a gene could be defined as any hereditarY infonnation for which there is favorable or unfavorable selection bias equal to several or rnany tirnes its rate ofendogenaus change", p. 24, 25 [emphasis in the original}. As noted above Dawkins subsequently chose the term "genetic replicator" as a general replacernent for "gene", which is used in these quotations in its functional and generalised sense.

20

See Dawkins, Blind Watchmaker, pp. 123-126.

Dawkins originally termed vehicles "survival rnachines" (Dawkins, Seljish Gene, pp. 46-65), but chose the term vehicle in order to ensure that no confusion occurred between the 1ogical category of entities that potentially survive indefinitely (genetic replicators) and those entities by which the genetic replicators are carried (vehicles); see Dawkins, 'Replicators and Vehic1es' p. 50. An alternative coinage to Dawkins' "vehicle" is Hull's "interactor" (David L. Hull, 'lndividuality and Selection' Annual Review of Ecology and Systematics 11 (1980): 311-332 at pp. 317-320). 21

22

Dawkins, 'Replicators and Vehicles' p. 51. See also Dawkins, Extended Phenotype, p. 114.

2. Elements of the Evolutionary Process

9

These definitions of replicators and vehicles are very general, and the following sections will make use of them in characterising evolutionary processes and their consequences. Because current biological research is generally phrased in terms of nuclear genes as replicators or "units of inheritance", and the organism as the prime vehicle or "Ievel of selection", these will provide the focus for the remainder of this initial discussion, with different Ievels being explicitly considered in the following section. b) Variation Replicators are defined in terms of copying, but every copying process can introduce errors, and hence variation among the copies. New forms of genetic replicators arise through a process known as mutation, as a result of causes termed mutagens. It is an important assumption of evolutionary theory that mutations are not biased with respect to improvements to the phenotype. This is supported by Observation of mutagens such as X-rays and cosrnic-rays, which indicates that they do not provide consistently advantageous mutations to the organisms being studied. The replication process for nuclear DNA is extremely faithful, with an average mutation rate in the order of one per cent per five rnillion replication generations, in the absence of natural selection. 23 There is considerable variance around this value, however, with every locus on the chromosome having its own characteristic rate, and considerable differences existing between species. 24 Independent of the mutationrate at each locus is the likelihood that mutations will occur in particular directions. "Mutation pressure" exists when there is an imbalance between "forward" and "backward" mutations, and can Iead to bias towards one form without the operation of natural selection. This is a very weak force, however, and the favoured form will not systematically

23 Dawkins, Blind Watchmaker, p. 125. In order to make this Ievel of accuracy intelligible, Dawkins considers a group oftypists, and calculates that "to match DNA with no natural selection, the typists would each have to be able to type the whole of the New Testament with only one error" (ibid., p. 125). To match the accuracy of replication after natural selection a typist "would have to be accurate enough to make only a single error in typing the Bible 250,000 times at a stretch" (ibid., p. 124).

24 See e.g., John Maynard Smith, The Evolution of Sex (Cambridge: Cambridge University Press, 1978), p. 189 [hereafter Maynard Smith, Evolution of Sex].

10

ll. The Elements of Evolution

Iead to increased survival of the replicators, the essence of the evolutionary process. 25 Recent theoretical developments suggest that genetic variation may play two fundamentally distinct roles in the evolutionary process. That traditionally recognised is to cause functional differences among vehicles, which Ieads to the differential survival of replicators through the process of natural selection. Without such variation adaptive changes in organisms could not take place. An important aspect of this type of variation is that the evolutionary process itself will tend to eliminate it, by selecting the functionally better alternative offered. 26 Biologists generally assume that sufficient relevant variation will exist for selection to act upon, on the basis that field and laboratory observations generally show adaptive changes in the appropriate qualities of the population.27 A fascinating example is the case of "industrial melanism" in the peppered moth, where the consequences of English industrialisation caused a substantial replacement of the light by the dark form. Now that air quality is improving the process has reversed. 28 The second role of variation results from its being selected for per se, as part of the evolutionary process. Multicellular organisms have important advantages, especially in terms of their complexity, but they face a critical disadvantage in their vulnerability to parasites in the broad sense of the term. In the competition

25 Mutationism is the view that the creative force of evolution is played by mutation, with only a rninor role for selection. Fora critical discussion see Dawkins, Blind Watchmaker pp. 305 ff. 26 "When trait differences correlate directly with genetic differences the reproductively inferior trait is maximally vulnerable to elirnination by selection." Richard D. Alexander, The Biology of Moral Systems, Foundations of Human Behavior Series (Hawthome, NY: Aldine de Gruyter, 1987) at p. 22 [hereafter Alexander, Moral Systems]. This apparently paradoxical result was clearly appreciated by Darwin, who recognised that traits such as the wings of bats would be "rendered constant by long-continued natural selection" (Darwin, Origin of Species, p. 474). This type of selection is thus sometimes called stabilising selection, because it tends to reduce genetic and expressed variability in populations, see e.g., John Tooby and Leda Cosrnides, 'The Past Explains the Present: Emotional Adaptations and the Structure of Ancestral Environments' Ethology and Sociobiology 11(4-5) (1990): 375-424, pp. 397-398 [hereafter Tooby and Cosrnides, 'Past Explains the Present']. 27 "When a sexual population is exposed to new selection pressures, for exarnple under domestication, or in the laboratory, or in nature when there is a sudden change in environmental conditions, there is usually rapid and adaptive responses in the constitution of the population." Maynard Srnith, Evolution of Sex, p. II. 28 See e.g., Richard C. Lewontin, 'Adaptation' Scientific American 239(3) (September 1978): 156-169 at p. !57 [hereafter Lewontin, 'Adaptation'); H.B .D. Kettlewell, The Evolution of Melanism (Oxford: Oxford University Press, 1973); Dawkins, Extended Phenotype, pp. 92-93.

2. Elements of the Evolutionary Process

11

between parasites and hosts, the latter have a Ionger generation time, often by several orders of magnitude. The consequence for asexually reproducing species is that they are likely to lose this "evolutionary arrns race": 29 once an organisrn is susceptible to a parasite, all its clonal offspring will also be vulnerable because the parasite will have 'cracked their code'. An important hypothesis developed recently by a nurnber of authors30 is that the need to provide genetic variation to prevent such parasitisrn led to the evolution of sex.31 Parasites by their nature do not adapt to the functional consequences of genetic replicators, 32 but rather to their immediate biochernical consequences, the proteins which provide rnicro-environrnents within the organisrn in which parasites can live and rnultiply. 33 In sexual species the

29 Such dynamic cornpetitive relationships play an irnportant roJe in evolution; see generally Richard Dawk.ins and John R. Krebs, 'Arms Races Between and Within Species' Proceedings of the Royal Society of London B 205 (1981): 489-511 [hereafter Dawkins and Krebs, 'Arms Races']. 30 The dassie paper in this Iiterature is Williarn D. Hamilton and Marlene Zuk, 'Heritable True Fitness and Bright Birds: A RoJe for Parasites?' Science 218 (22 October 1982): 384-387 [hereafter Harnilton and Zuk, 'Heritable True Fitness']; seealso Williarn D. Hamilton, 'Mate Choice Near or Far' American Zoologist 30(2) (1990): 341-352. See generally Williarn D. Hamilton, Robert Axe1rod, and R. Tanese, 'Sexual Reproduction As an AdaptationtoResist Parasites (A Review)' Proceedings of the National Academy of Seiences ojthe United States ojAmerica 87(9) (May 1990): 3566-3573. 31 The reasons for the evolution of sex is a difficult problern in evolutionary theory, and this account of the parasite theory should not be interpreted as irnplying that it has been proved correct. Even if the parasite theory is valid, that does not necessarily rnean that other hypotheses are false; it is possible for explanations frorn different perspectives and at different Ievels tobe sirnultaneously true, as discussed in the next chapter. For general reviews see Stephen C. Stearns, 'Why Sex Evolved and the Difference it Mak.es' in Stephen C. Stearns (ed.}, The Evolution oj Sex and lts Consequences, pp. 15-31, Experentia Supplernentum Vol. 55 (Basel: Birkhäuser Verlag, 1987); Michael T. Ghiselin, 'The Evolution of Sex: A History of Cornpeting Points of View' in Richard E. Michod and Bruce R. Levin, (eds.), The Evolution oj Sex: An Examination oj Current ldeas, pp. 7-23 (Sunderland, MA: Sinauer, 1988). See also, in addition to the contributions to these collections, John Maynard Srnith, 'The Ecology of Sex' in John R. Krebs and Nicholas B. Davies (eds.}, Behavioural Ecology: An Evolutionary Approach, pp. 201-221, [1978} 2nd ed. (Oxford: Blackwell Scientific Publications, 1984); Maynard Srnith, Evolution ofSex; Michael T. Ghiselin, The Economy of Nature and the Evolution of Sex (Berkeley, CA: University of Califomia Press, 1974); George C. Williarns, Sex and Evolution (Princeton, NJ: Princeton University Press, 1975).

32 'Normal' arrns races, such as between cat species and rnice species, depend on the functional effects of &enetic replicators, such as speed of movement. See generally Dawk.ins, Extended Phenotype, pp. 55-80. 33 See e.g., John Tooby and Leda Cosrnides, 'On the Universality of Human Nature and the Uniqueness of the Individual: The RoJe of Genelies and Adaptation' Journal oj Personality 58(1) (March 1990): 17-68, p. 34 [hereafter Tooby and Cosrnides, 'Universality and Uniqueness'}.

12

Il. The Elements of Evolution

mixing of genetic replicators associated with the process of meiosis 34 allows diversity to emerge at this sub-functionallevel. The process through which this emerges is known as "frequency-dependent selection", a complex process that can be intuitively understood by imagining parasites becoming adapted to the more common proteins 'caused by' 35 the more common genetic replicators in the gene pool. The heavier parasitism on the most frequent forms thus Ieads to positive selection for the less common alleles, they too become more common, and the process repeats itself, resulting in a !arge amount of diversity within the gene pool. 36 The elegance and power of this hypothesis is illustrated in its explanation of additional phenomena, such as mate choice on the basis of "good genes",37 and

34 Meiosis involves the mixing of genetic replicators in cell division, as compared to the normal division of cells with no genetic change (other than mutation) known as mitosis. 35 The effect of replicators on vehicles and their constituent parts, in this case proteins, results from the complex interaction between replicators and all the aspects of the environment (including other replicators), a process known as ontogeny or development. The standard practice, followed here, is to refer to genetic replicators 'for' particular traits, or inversely, traits being 'caused by' specific replicators. The use of such shorthand expressions has been interpreted by critics of evolutionary approaches to human characteristics as ignoring the roJe of the environment, and implying a form of genetic determinism. Unfortunately a more correct phrase, conveying the meaning that 'genetic replicator A Ieads to trait X in an organism, rather than the trait Y resulting from its allele a, assuming all other conditions remain the same', would be so unwieldy as to result in unintelligible text. Bateson advocates dispensing with such shortcuts completely: "I believe, then, that the 'gene for a character' language should not be used even as a shorthand." (P. Patrick 0. Bateson, 'Behavioural Development and Evolutionary Processes' in King's College Sociobiology Group (eds.), Current Problems in Sociobiology, pp. 133-151 (Cambridge: Cambridge University Press, 1982), p. 135 [hereafter Bateson, 'Behavioural Development']. Ironical1y Bateson makes use of just such abbreviations later in the same paper: "W gi ves rise to normal wings, vv to crossveinless wings and Vv in anormal environment to normal wings." (ibid., p. 145); "MM and Mm blue tits cannot openmilk bottles, but mm blue tits can." (ibid. [original emphasis in both quotations)). The fact that both these sentences are followed by explanations in parentheses demonstrates that Bateson' s precept is unworkable, and that the most appropriate path is to use shorthand expressions which are then qualified by an explanatory passage such as this note. 36 A gene pool is the set of genetic replicators in a population. A number of formal models of this frequency-dependent process have been presented. See e.g., William D. Harnilton, Peter A. Henderson, and Nancy A. Moran, 'Fluctuation of Environment and Coevolved Antagonist Polymorphism as Factcrs in the Maintenance of Sex' in Richard D. Alexander and Donald W. Tinkle (eds.), Natural Selection and Social Behavior: Recent Research and New Theory, pp. 363-381 (New York: Chiron Press, 1981), pp. 368 ff.; William D. Harnilton, 'Sex versus Non-Sex versus Parasite' Oikos 35(2) (1980): 282-290.

37 See e.g. 01enn Hausfater, H. Car1 Gerhardt, and Georg M. Klump, 'Parasites and Mate Choice in Gray Treefrogs, Hyla versicolor' American Zoologist 30 (1990): 299-311, and the remainder of this special issue devoted to the topic; Hamilton and Zuk, 'Heritable True Fitness'; William D. Rarnilton and Marlene Zuk, 'Heritable True Fitness and Bright Birds: A RoJe for Parasites?' Science

2. Elements of the Evolutionary Process

13

higher Ievels of genetic variation than would appear compatible with selection having acted on functional traits. 38 c) Selection

Selection is the driving force of evolution, generating the directional change which results in the adaptive complexity we know as life. lt does this by eliminating particular vehicles, leading to the differential survival of the active germ-line replicators which are unevenly distributed between the various vehicles. Darwin chose the term "natural selection" by analogy with the artificial selection that humans apply to domesticated plants and animals. 39 Rather than the human eye, forces such as climate, food shortages, predators, parasites, and disease are the selective agents.40 These factors Iead to a generalised competition for appropriate resources in the "whole economy of nature"41 of which the competition for mates in sexual species is a particularly interesting category. Darwin termed this "sexual selection" to differentiate it from natural selection, because it can cause the emergence of traits which lower resistance to other selective forces, as in the elaborate tails of some male birds.42 The replicator/vehicle perspective adopted here is very general, and it is the power of selection at the various Ievels in the hierarchy of life that determines

218 (22 October 1982): 384-387; Bobbi S. Low, 'Pathogen Stress and Polygyny in Humans' in Laura Betzig, Monique Borgerhoff Mulder, and Paul Turke (eds.), Human Reproductive Behaviour: A Darwinian Perspective, pp. 115-128 (Cambridge: Cambridge University Press, 1988). 38 See e.g., Eviatar Nevo, 'Genetic Variation in Natural Populations: Patterns and Theory' Theoretical Population Biology 13 (1978): 121-177; A.M. Brues, 'Selection and Polymorphism in the ABO Blood Groups' American Journal of Physical Anthropology 12 (1954): 559-597; A. M. Brues, 'Stochastic Tests of Selection in the ABO Blood Groups' American Journal of Physical Anthropology 21 (1963): 287-299; John Tooby, 'Pathogens, Polymorphism, and the Evolution of Sex' Journal of Theoretical Biology 97 (1982): 557-576; Tooby and Cosmides, 'Universality and Uniqueness', p. 33. 39 "I have called this principle, by which each slight variation, if useful, is preserved, by the term of Natural Selection, in order to mark its relation to man's power of selection." Darwin, Origin of Species, p. 61.

40

Ibid., p. 67, passim.

41

lbid., p. 62.

42 lbid., pp. 87 f f. Sexual selection has been a fertile field of research for mathematically inclined biologists since the classic treatment by R.A. Fisher in The Genetical Theory of Natural Selection (Oxford: Clarendon Press, 1930) [hereafter Fisher Genetical Theory] .

14

ll. The Elements of Evolution

where adaptation is to be found. These Ievels will be discussed below, but it is appropriate to develop a general framework at this stage in which their interrelationship can be understood. The presentation follows Hamilton's version of Price's general selection model,43 as an aid to clarity in this important problem, and to provide a foundation for later discussions. lt is weil suited to the replicator/vehicle approach, because it is not limited to particular forms of vehicles, and can deal in a recursive fashion with all of the Ievels of a hierarchy while separating each of them in the analysis: Consider a population consisting of a mixture of particles, and suppose we are interested in the frequency of a certain type of particle G. Suppose the particles are grouped: Iet the subscript s denote the s'th subpopulation. For subpopulation and for the whole we define parameters relevant to natural selection as follows:

Number of particles: Frequency of G: Mean fitness:

Subpopulation Whole population n, N = r.n, q = r.n,q,IN q, w = r.n,w,IN w,

Fitness measures the amount of successful replication of particles in one 'generation'. Thus the total population of the next generation will be N' = r.n,w,. The symbol ' denoting 'next generation' is used again in the same sense in the following addition to notation:

Change of frequency of Gin one generation:

Subpopulation

lig,

= q ',- q,

Whole population

liq

= q'- q

With such notation it is easy to derive: [1] w liq = r.n,w, (q,-q) IN+ l:n,w, liq, IN = Covariance(w, , q,) + Expectation (w, , liq,) where Covariance and Expectation are understood to involved weighting by the n, as indicated.44

43 William D. Hami1ton, 'Innate Social Aptitudes of Man: An Approach frorn Evolutionary Genetics' in Robin Fox (ed.), Biosocial Anthropology, pp. 133-155 (New York: Wiley, 1975), pp. 136 ff [hereafter Hamilton, 'Innate Social Aptitudes']; George R. Price, 'Selection and Covariance' Nature 227 (1 August 1970): 520-521 ; George R. Price, 'Extension of Covariance Selection Mathematics' Annals of Human Genetics 35(4) (April 1972): 485-490. 44

Hamilton, 'Innate Social Aptitudes', p. 28 [style approximately that of the original].

2. Elements of the Evolutionary Process

15

This first (covariance) term shows the contribution of intergroup, and the second that of intragroup (or individual) selection, where 'group' has a very general meaning. This generality is an important aspect of the analysis, as the equation can be recursively applied to include the next Ievel of the hierarchy, by expanding w, !!.q,. An alternative formulation uses the regression coefficient of w, on q, (ß 1), showing the dependence of selection on the variability in the units: w!J.q

= ~~ Variance (q,) + Expectation (w,, !J.q,)

lt appears that in general the effectiveness of selection at different Ievels

depends primarily on the amount of difference between the entities involved, the heritability of differences, and generation time.46

Combining this Price-Harnilton model with the forms of variation discussed above indicates that the process of selection will have two distinct effects on vehicles. The first and best known effect of selection is to create traits in vehicles through incremental change,47 in directions which enable the survival of the replicators 'for' these vehicles over evolutionary time. These characteristics are generally known as "adaptations" and will be exarnined in more depth in the next chapter, but it is important to note at this point that adaptation is a general concept, which potentially applies to any of the Ievels of selection, and is thus not lirnited to organisms themselves. A process of frequency-dependent selection operates, in this form of selection, among the replicators, because the effects of multiple genetic replicators tagether with the extemal environment result in the expression of

45

Hamilton, 'Innate Social Aptitudes', p. 137.

See Lewontin, 'Units of Selection', p. 8; Richard D. Alexander, Darwinism and Human Affairs (Seattle, WA: University ofWashington Press, 1979), esp. pp. 37 ff. [hereafter Alexander, Human Affairs]; Hamilton, 'Innate Social Aptitudes', p. 136; Williarn G. Eberhard, 'Evolution in Bacterial Plasmids and Levels of Selection' Quanerly Review of Biology 65(1) (March 1990): 3-22 esp. p. 17 [hereafter Eberhard, 'Levels of Selection'); Williarns, Adaptation and Natural Selection, esp. pp. 20-55. 46

47 Theincremental nature ofthe change results from the fact that selection only 'chooses' arnong the best of the alternatives presented to it by mutation and drift. The vast rnajority of such alternatives are likely tobe detrimental to replicator survival, and those that are beneficial will in all likelihood be small quantitative changes, as the probability of such advantageaus variations occurring decreases drarnatically with the number of changes that are made to the existing trait. Darwin made incremental change one of the pillars of his theory: "lf it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find no such case." Darwin, Origin of Species, p. 189.

16

II. The Elements of Evolution

observed traits. An intuitive feel for this can be gained by considering a group of replicators that together form the gene pool for a herbivore. A replicator 'for' sharper cutting teeth would presumably be selected against in this environment, for example, whereas in a carnivore gene-pool it could be very successful. 48 lt is this type of selection that reduces yariation among the genetic replicators, because the least successful tend to be eliminated from the gene pool. The mathematical analysis of such processes generally utilises the concept of an evolutionarily stable strategy (ESS), which has been defined as "a strategy such that, if most of the members of a population adopt it, there is no 'mutant' strategy that would give higher reproductive fitness". 49 The second effect of selection is also associated with frequency-dependence, but this occurs among vehicles, as in the parasite-pressure explanation of sex discussed above. The key element of this process is that the pressure of selection on a particular vehicle depends upon the frequency of the different vehicle types in the population. The result is selection for diversity among genetic replicators, although this may not result in significant functional differences in their expressed characteristics, as with sub-functional variation resulting from the sexual process. d) Genetic Drift

Genetic drift refers to purely random or non-repetitive alterations in the relative frequencies of genetic replicators, due for example to accidents affecting a section of the population. It has received considerable attention from critics of the adaptive nature of evolutionary change, who have focused on it as a mechanism for the production of non-adaptive characters. 50

48 Dawkins has termed this "the Jack Sprat principle", Dawkins, Extended Phenotype, p. 239, and illustrated it with the example of a rowing crew (Dawkins, Selfish Gene, pp. 38-39, passim). 49 John Maynard Smith and G.R. Price, 'The Logic of Anima! Conflict' Nature 246 (2 November 1973): 15-18, p. 15. This is a useful intuitive definition but identification of actual evolutionarily stab1e strategies may require an expressly mathematical and dynamic approach, as shown by Haigh' s correction of the initial solutions to this problern (John Haigh, 'Game Theory and Evolution' Advances in Applied Probability 7(1) (1975): 8-11). Seegenerally John Maynard Smith, Evolution and the Theory of Games (Cambridge: Cambridge University Press, 1982), pp. 11-20 [hereafter Maynard Smith, Theory of Games].

°

5 For example, "the finiteness of real populations results in random changes in gene frequency, so that, with a certain probability, genetic combinations with lower reproductive fitnesswill be fixed in a population." Richard C. Lewontin, 'Sociobiology as an Adaptionist Program' Behavioral

2. Elements of the Evolutionary Process

17

While such interpretations often draw on theoretical analyses of drift by Wright, he hirnself has explicitly opposed the interpretation of drift as leading to non-adaptive or maladaptive outcomes, stating that: Pure random drift Ieads "inevitably to degeneration and extinction." I have attributed apparent nonadaptive taxonomic differences to pleitropy, where not merely ignorance [sie] of an adaptive significance.51

In contrast, drift may allow the attainment of more optimal traits than would have been achieved through normal natural selection, an argument that can be visualised in terms of the topography of Wright's "adaptive landscape". Without drift, once a lineage has started to develop in a particular direction the ratchet of natural selection will ensure that this direction is continued, even if it Ieads only to an intermediate rather than the highest possible peak. 52 Drift in combination with selection can overcome this problem, by leading the species to explore the region araund the slope in the adaptive Iandscape which it is currently ascending: Creativity is raised to the second power, however, if the field of variability is amplified by random differentiation among numerous partially isolated local populations, and selection is amplified by selective diffusion from those local populations that happen to have acquired superior coadaptive systems of genes by shifts to control by superior peaks in the adaptive landscape. 53

e) Isolation and Speciation

The processes of mutation and selection can generate adaptation, but not the approximately two rnillion different species,54 each adapted to its own Science 24(1) (January 1979): 5-14, at p. 17 [hereafter Lewontin, 'Adaptionist Program']. This proposition also plays an important role in punctuated equilibria and species selection explanations; see e.g., Stephen Jay Gould and Niles Eldredge 'Punctuated Equilibria: The Tempo and Mode of Evolution Reconsidered' Paleobiology 3 (1977): 115-151. 51 Sewall Wright, 'Genie and Organismic Selection' Evolution 34(5) (September 1980): 825-843, p. 839 [hereafter Wright, 'Genie and Organismic Selection' ]. For discussions of "Wright's Rule" and "the Sewall Wright effect" see e.g., Dawkins, Extended Phenotype, pp. 104, 108. 52

"A gene is selected on how weil its effects fit in with those of the current genetic system.

In terms of the adaptive topography, the population always tends to move upward under selection.

A novel mutation, adding a new dimension, will be favourable selected if it elevates the currently Controlling peak" (Wright, 'Genie and Organismic Selection', p. 830). 53

Ibid. , p. 841.

Lewontin, ' Adaptation', p. 157. Lewontin notes that at least 99.9 per cent ofthe species that have ever existed are now extinct (ibid.). 54

2 Elwonhy

18

li. The Elements of Evolution

particular environment. This speciation results from the ending of the mixing of genetic replicators within gene pools, with the result that sections of the gene pool diverge to such an extent that the members of the different groups can no Ionger successfully interbreed. The most likely way for this to occur is through the geographical isolation of the parts of the group. This "allopatric speciation" prevents mixing of the gene pools, which then separate due to genetic drift, or through adaptation to different conditions. This is more probable than "sympatric speciation",55 where gene flow within the gene pool makes it unlikely that a reproductively isolated group will emerge.56 The process of isolation concludes this brief review of the elements of the evolutionary process, and the following section assesses at which Ievels they can be expected to operate.

3. Levels of Selection a) Genets

An important consequence of the replicator/vehicle perspective is that the entities to be explained shift from being the units of inheritance to being the organisms that we see about us. Replicators 'exist' in a similar manner to elementary particles in physics, and just as the 'normal' physical world of mass and motion should be interpretable in terms of these fundamental units, so the 'normal' biological world of organisms and their characteristics should be interpretable in terms of replicators. From the appearance of the earllest replicators competition would have led to comparative success to those who exerted "power" over their environment, especially the environment provided by other replicators. Remaining a solitary replicator in such a Situation would not have been an evolutionarily stable strategy, and successful replicators would be expected to be members of coalitions which cooperated in their phenotypic effects. This would have ss Sympatric speciation is the term given to reproductive isolation when species continue to occupy the sarne geographical area. Fora listing of various types see Roben A. Foley, Another Unique Species: Patterns in Human Evolutionary Ecology (Harlow, Essex: Longman Scientific & Technical, 1987) Table 9, p. 247 [hereafter Foley, Another Unique Species]. 56 See e.g., Alexander, Human Affairs, p. 16; Dawkins, Blind Watchmaker p. 239, for discussions of the imponance of speciation.

3. Levels of Selection

19

enabled these cooperative coalitions to create more effective vehicles than those of isolated replicators, leading to the development of the forerunners of modern cells.57 Hence the origin of unicellular or acellular organisms appears explicable on the basis of replicator competition, and these are a very important class of living forms. 58 The very success of such unicellular organisms, however, Ieads to examination of why they have all remained small, whereas large organisms are all complex multicellular clones. The root of the answer appears to lie in the need for functional complexity in such organisms, which endows them with organs and traits capable of underpinning replicator survival. 59 Complexity, however, cannot simply be achieved by expansion of the size of cells: An amoeba may give rise to two daughters by splitting down the middle, but an eye, or a heart, can not give rise to two daughter eyes or two daughter hearts by binary fission. Eyes and hearts are so complex that they have to be developed from small beginnings, built by orderly cell division and differentiation.60

The clear difference between growth and reproduction in most animals appears to have led to general neglect of an analysis of the functional difference between the two processes by zoologists. lt is however a problern that is of direct concern to botanists, where the concept of an individual is much more difficult to define: The idea of a plant as a population of parts is not a trite analogy but important for understanding the population biology of plants .... The individual fruit fly, flour beetle, vole, rabbit, flatworrn or elephant is a population at the cellular but not at any higher Ievel. Starvation does not change the number of legs, hearts or livers of an animal, but the effect of stress on a plant is to alter both the rate of forrnation of new leaves and the rate of death of old ones: a plant may react to stress by varying the number of its parts.61

57 This view meshes with the hypothesis that organelles such as mitochondria and chloroplasts originated from parasitic prokaryotes as advocated by Margulis (Margulis Origin of Eukaryotic Cells, esp. pp. 45-68; Margulis, Symbiosis in Cell Evolution, esp. pp. 1-14). 58

See e.g., Margulis, Origin of Eukaryotic Cells, passim.

This flexibility, together with the 'power' over the environment that it provides, are the fundamental reasons for the emergence of all vehicles: "the whole reason for phenotypes having evolved is that they provide flexibility in meeting environmental contingencies that are only predictable on short-terrn bases" (Alexander, Human Affairs, p. 14). 59

60

Dawkins, 'Replicators and Vehicles', p. 54.

John L. Harper, Population Biology of Plants (London: Academic Press, 1977), pp. 20-21 [hereafter Harper, Population Biology]. 61

2•

20

II. The Elements of Evolution

On the basis of this complexity Harper has proposed that two fundamental types of individual plant exist: one corresponding to growth and development and termed the "ramet", and the other associated with genetic reproduction, called the "genet". 62 Dawkins has developed Harper's categories into a functional explanation of organism development with the use of a thought experiment concerning two simple plants like water lilies, one of which grows to a certain size and then reproduces (R), and the other which simply grows but may experience fission at the outer edges (G): In order to put together a complex multicellular organ you need a developmental sequence. A complex developmental sequence has to have evolved from an earlier developmental sequence which was slightly less complex. There has to be an evolutionary progression of developmental sequences, each one in the series being a slight improvement on its predecessor. G does not have a recurring developmental sequence other than the high-frequency cycle of development at the single-celllevel. Therefore it cannot evolve multicellular differentiation and organ-level complexity. To the extent that it can be said to have a multicellular developmental process at all, that development continues non-cyclically through geological time: the species makes no separation between the growth time-scale and the would-be evolution time-scale. The only high-frequency developmental cycle available to it is the cell cycle. R, on the other band, has a multicellular developmental cycle which is fast compared with evolutionary time. Therefore, as the ages succeed, later developmental cycles can be different from earlier developmental cycles, and multicellular complexity can evolve. We are moving towards a defmition of the organism as the unit which is initiated by a new act of reproduction via a single-celled developmental 'bottleneck' .63

This perspective means that a life history of growth, and then reproduction through the single-celled stage, become the central characteristics of the organism. 64 62 "The 'ramet' is the unit of clonal growth, the module that may often follow an independent existence if severed from the parent plant" (Harper, Population Biology, p. 24). "One Ievel is described by the nurober of individuals present that are represented by original zygotes. Such units represent independent colonizations. Such individuals will be called genets" (ibid., p. 26; [emphasis in the original]). A sirnilar proposal was made by Janzen, who proposed terming "evolutionary individuals" what Rarper calls "genets" (Daniel H. Janzen, 'What are Dandeiions and Aphids?' American Naturalist 111:979 (1977): 586-589, esp. p. 586).

Dawkins, Extended Phenotype, p. 258 [emphasis in the original]. "An organism is the physical unit associated with one single life cycle. Replicators that gang up in multicellular organisms achieve a regularly recycling life 63 64

3. Levels of Selection

21

Corresponding to these two facets of organisms are the two roles that they play in the evolutionary process. One is that of a vehicle for 'its' genetic replicators, which represents one of the Ievels at which selection may act. If one animal in a group dies at immaturity because of ineffective foraging, while the others survive, then such selection will ceteris paribus Iead to a decline in the frequency of the replicators 'for' ineffective foraging in the gene pool. The second aspect is that organisms are the mechanisms by which genetic replicators affect the world about them. lt is only through organisms that replicators can exert effort, and it is the complex developmental path of organisms that allows functional complexity to emerge in, for example, morphology or psychology. Conventional terminology does not differentiate between these two roles of organisms, but the distinction is so fundamental to the following discussion that the use of the same terms could result in considerable confusion. In order to aid clarity a distinction will therefore be made between these concepts, with conventional expressionssuch as "individual" or "organism" being used to refer to organisms as mechanisms exerting effort in the world about them. For the reproductive aspect, as a vehicle on which selection operates, Harper's term "genet" will be used. b) Kin-Gmups

A kin-group describes the groupings of kin in a population on which selection may act. lt was the profound insight of Harnilton that quite distinct effects would result from selection acting on genetic relatives as compared to random members of a population: For a gene to receive positive selection it is not necessarily enough that it should increase the fitness of its bearer above the average if this tends to be done at the heavy expense of related individuals, because relatives, on account of their common ancestry, tend to carry replicas of the same gene; and conversely that a gene may receive positive selection even though disadvantageous to its bearers if it causes them to confer sufficiently !arge advantages on relatives.65

history, and complex adaptations to aid their preservation, as they progress through evolutionary time." Jbid., p. 259. 65 William D. Hamilton, 'The Genetical Evolution of Social Behaviour. 11' Journal of Theoretical Biology 7(1) (July 1964): 17-52, p. 17 [hereafter Hamilton, 'Genetical Evolution 11']. The frrst exposition of this seminal theory was William D. Hamilton, 'The Evolution of Altruistic Behavior' American Naturalist 97(896) (September-October

22

li. The Elements of Evolution

This can be formalised in terms of the Price-Ramilton model considered above, where w represents mean fitness, q the frequency of the particles (G), and there is a binomial distribution of groups with parameters (q,n), leading to variance of q. of 1/n pq. 66 In tbis framework Rarnilton considers an asexual version in which an 'altruistic' 67 individual sacrifices k units of bis own fitness in order to contribute K units to the combined fitness of bis (n-1) companions. Assurne further that the particles (Gs) assort preferentially with their own type, rather than being distributed randomly through the population, and that within a group the correlation of relatedness is F. Rarnilton shows that in this case: [2.1]

w t::.q = p q (FK- k)

68

implying that 'altruistic' behaviour with costs to the individual will be selected for when: K/k > 1/F 69

[2.2]

When the analysis is extended from sexual to asexual reproduction, the specific formulation of equation 2.1 is necessarily altered, but the general conclusion summarised in equation 2.2 remains unchanged.70 These results have been derived witbin the Price-Ramilton framework. wbich is conceived in terms of the effects of selection on particles in the population. Fitness (w) in this definition is a relatively simple and easily measurable

1963): 354-356. One example of the imponant insights provided by this perspective is the explanation of the role of the sterile castes in the social insects; see e.g., William D. Hamilton, 'Altruism and Related Phenomena, Mainly in the Social Insects' Annual Review of Ecology and Systematics 3 (1972): 193-232; Robert L. Triversand Hope Hare, 'Haplodiploidy and the Evolution of The Social Insects' Science 191(4224) (23 January 1976): 249-263. 66

Hamilton. 'Innate Social Aptitudes'. pp. 138, 139.

"Altruism" is used throughout the text to refer to behaviour which results in net costs to an organism and benefits to vehicles other than the genet i.e., it may be devoted to or divided between kin-groups and groups. To differentiale this specialised usage from its more general meaning of "the principle or practice of unselfish concern for the welfare of others" (Collins, Dictionary of the English Language (London: Collins, 1979), s.v. "altruism" [hereafter Coltins Dictionary]) it will be generally rendered 'altruism'. 67

68

Hamilton, 'lnnate Social Aptitudes', p. 139.

69

Jbid.

70

lbid., p. 140.

3. Levels of Selection

23

concept: "the amount of successful replication of particles in one 'generation'".71 Rather than the "gene's-eye view" of the replicator/vehicle approach, conventional biology adopts a "human's-eye view"; interpreting the world primarily in terms of organisms and their characteristics, and only secondarily in terms of genetic replicators. 'Pure' fitness (w) must thus be replaced with the concept of "inclusive fitness", in order to allow a linktobe formed between the observable behaviour of individual organisms and the underlying Ievel of genetic replicators: 72 Inclusive fitness may be imagined as the personal fitness which an individual actually expresses in its production of adult offspring as it becomes after it has been frrst stripped and then augmented in a certain way. It is stripped of all components which can be considered as due to the individual's social environment, leaving the fitness which he would express if not exposed to any of the harms or benefits of that environment. This quantity is then augmented by certain fractions of the quantities of harm and benefit which the individual hirnself causes to the fitness of his neighbours. The fractions in question are simply the coefficients of relationship appropriate to the neighbours whom he affects: unity for clonal individuals, one-half for sibs...73

Unfortunately the inclusive fitness concept, although apparently simple, is remarkably subtle, depending for any particular individual on the effects of its behaviour on potentially large numbers of other individuals and itself, as compared to a hypothetical 'benchmark' state of nature, such as the total inactivity of the focal individual. This subtlety has led to a large number of errors in attempts to apply inclusive fitness theory to theoretical and empirical aspects of kin selection phenomena.74

71

lbid., p. 136.

"Inclusive fitness may be defined as that property of an individual organism which will appear to be maximised when what is really being maximised is gene survival. This is not his own definition, but Dr. Hamilton allows me to say that it is the ideal inclusive fitness to which bis actual concept was an approximation." Dawkins, 'Replicator Selection', p. 63. 72

73 William D. Hamilton, 'The Genetical Evolution of Social Behaviour. I' Journal of Theoretical Biology 7(1) (July 1964): 1-16, p. 8 [hereafter, Hamilton, 'Genetical Evolution I']. A table of the probabilities that replicators in normal diploid and haplodiploid species will be identical by descent is provided in Dawkins, 'Replicator Selection', Table 2 p. 66. 74 See e.g., Richard Dawkins, 'Twelve Misunderstandings of .Kin Selection' Zeitschriftfür Tierpsychologie 51 (1979): 184-200; Alan Grafen, 'How Not to Measure

24

li. The Elements of Evolution

The approach taken in this work is not to focus on the organism whose selfsacrificial behaviour Ieads to benefits to its kin, but on the kin-group as a vehicle which can then be approached in a similar manner to the genet. 75 The effort of individuals is independently analysed as the mechanism by which the vehicles, in this case kin-groups, achieve their 'goals'. Thus instead of attempting to analyse the kin-group in terms of an essentially counterfactual estimation/6 the organisms within the kin-group are assumed so to behave as to ensure the survival of the kin-group's genetic replicators. c) Groups

Apparently largely because of "good of the species" models of group selection,77 scepticism towards group selection is widespread among biologists,78 so that it can be said that "anti-group selectionism has been

Inclusive Fitness' Nature 298 (29 July 1982): 425-426. In addition to being frequently misunderstood Hamilton's papers have also been widely miscited: see e.g., Jon Segar and Paul H. Harvey, 'The Evolution of the Genetical Theory of Social Behaviour' New Seienrist 87(1208) (1980): 50-51; Robert M. May and Miranda Robertson, 'Just So Stories and Cautionary Tales' Nature 286 (24 July 1980): 327-329, p. 326; Paul H. Harvey and Jon Segar, 'Misciting Latest' Nature 286(5775) (21 August 1980): 754; Dawkins, Selfish Gene, pp. 328-329. 75 Dawkins hirnself appears to have an ambivalent attitude to the presence of kingroups. In his general theory he recognises the possibility of their existence: "where they exist, tightly knit farnily bands, or 'kin groups', may be regarded as vehicles. But the general theory of kin selection does not depend upon the existence of discrete family groups. No vehicle above the organism vehicle need be postulated" (Dawkins, 'Replicators and Vehicles', p. 58). In practice, however, Dawkins appears to want to dispense with the concept: "there is, indeed, no need for the terrn kin selection to exist, and I suggest that we stop using it" (ibid., p. 67). 76 Dawkins views "the concept of inclusive fitness as the instrument of a brilliant last-ditch rescue attempt, an attempt to save the individual organism as the Ievel at which we think about natural selection" (Dawkins, Extended Phenotype, p. 187), and as the "Darwinian equivalent of the Ptolemaic epicycles" (Dawkins, 'Replicator Selection', p. 67).

77 Such group selectionist arguments are closely associated with the work of Wynn Edwards; see e.g., V.C. Wynn Edwards, Anima/ Dispersion in Relation to Social Behaviour (Edinburgh: Oliver & Boyd, 1962). 78 For example, "we painfully struggled back, harassed by sniping from a Jesuitically sophisticated and dedicated neo-group-selectionist rearguard, until we finally regained

3. Levels of Selection

25

embraced by the establishment as orthodox".79 It is ironic, given the importance of Hamilton's inclusive fitness to the overtuming of naive group selectionism,80 that biological orthodoxy has overshot Hamilton's own position: The usefulness ofthe 'inclusive fitness' approach to social behaviour (i.e. an approach using criteria like (bABK - k)>O) isthat it is more general than 'group selection', 'kin selection', or 'reciprocal altruism' approaches and so provides an overview even when regression coefficients and fitness effects are not easy to estimate or specify. As against 'group selection' it provides a useful conceptual tool where no grouping is apparent - for example, it can deal with an ungrouped viscous population where, owing to restricted rnigration, an individual's normal neighbours and interactants tend to be his genetica! kindred. Because of the way it was frrst explained, the approach using inclusive fitness has often been identified with 'kin selection' and presented strictly as an alternative to 'group se!ection' as a way of establishing altruistic social behaviour by natural selection (e.g. Maynard Srnith 1964; Lewontin 1970). But the foregoing discussion shows that kinship should be considered just one way of getting positive regression of genotype in the recipient, and that it is this positive regression that is vitally necessary for altruism. 81

Thus from this perspective kin-group selection is a particular form of group selection, where the correlation of relatedness F in equations 2.1 and 2.2 above is replaced by the coefficient of relationship between family members r. In the case, which will often be realised, where parents are from the same group, and hence possess a correlation of relatedness F, kin will exhibit higher r than that of outbred populations, due to the higher underlying Ievel of shared replicators.

Darwin's ground, the position that I am characterizing by the Iabel 'the selfish organism"' (Dawkins, Extended Phenotype, p. 6). Although there is little point of a Marxian-like debate over 'what Darwin really meant', a strong case can be made that Darwin's views were not incompatible with the form of group selection advocated here. 79 Dawkins, Extended Phenotype, p. 115. The attitude of most biologists is probably captured in the phrase "[i]t does not follow that, because a position is orthodox, it is wrong" (John Maynard Smith, 'Group Selection' Quarterly Review of Biology 51(2) (June 1976): 277-283, p. 277).

80 The classic attack on this form of group selection argument is that by Williams, where "the reader is directed to Harnilton's papers, which also anticipate a number of lines of reasoning developed elsewhere in this book" (Williams, Adaptation and Natural Selection, p. 197). 81 Hamilton, 'Innate Social Aptitudes', pp. 140-141. [Maynard Srnith 1964 = John Maynard Smith 'Group Selection and Kin Selection' Nature 201 (1964): 1145-1147; Lewontin 1970 = Lewontin, 'Units of Selection'].

26

ll. The Elements of Evolution

In order to emphasise this relationship Rarnilton suggests making the Iinkage clear in the terminology used, a recommendation that has been followed in this work by interpreting kin selection as acting on the kin-group vehicle: If we insist that group selection is different from kin selection the term should be restricted to situations of assortation definitely not involving kin. But it seems on the whole preferable to retain a more flexible use of terms; to use group selection where groups are clearly in evidence and to qualify with mention of 'kin'(as in the 'kingroup' selection referred to by Brown 1973), 'relatedness' or 'low migration' (which is often the cause of relatedness in groups), or eise 'assortation', as appropriate. The term 'kin se1ection' appeals most where pedigrees tend to be unbounded and interwoven, as is so often the case with man. 82

Of the processes that have been identified through which F may be lifted within a subgroup (deme) other than kinship relations, the most important appears to be migration. It is "low migration group selection" that forms the basis of most group-selectionist analyses,83 and the corresponding vehicle could thus be 82 Hamilton, 'Innate Social Aptitudes', p. 141. [Brown 1973 = Jerome L. Brown, 'Alternative Routes to Sociality in Jays- with a Theory for the Evolution of Altruism and Communal Breeding' American Zoologist 14 (1974): 63-80. My correction of citation]. 83 For sympathetic reviews of group selectionism see David Sloan Wilson, 'The Group Selection Controversy: History and Current Status' Annual Review of Ecology and Systematics 14 (1983): 159-187; Michael J. Wade, 'A Critical Review of the Models of Group Selection' Quarterly Review of Biology 53(2) (June 1978): 101-114. Some models bear a close resemblance tothat developed below, including Ilan Eshel, 'On the Neighbor Effect and the Evolution of Altruistic Traits' Theoretical Population Biology 3 (1972): 258-277) [hereafter Eshel, 'Neighbor Effect'] ; Scott A. Boorman and Paul R. Levitt, 'A Frequency-Dependent Natural Selection Model for the Evolution of Social Cooperation Networks' Proceedings ofthe National Academy of Seiences 70(1) (January 1973): 187-189; Richard Levins, 'Extinction' in M. Gerstenhaber (ed.), Same Mathematical Questions in Biology, Val. 2, pp. 77-107, Lectures on Mathematics in the Life Seiences (Providence, RI: The American Mathematical Society, 1970); Edward 0. Wilson, 'Group Selection and its Significance for Ecology' Bioscience 23(11) (November 1973): 631-8; Edward 0. Wilson, Sociobiology: The New Synthesis (Cambridge, MA: Harvard University Press, 1975) pp. 106-129, passim [hereafter Wilson, Sociobiology]. See also David Sloan Wilson, 'New Model for Group Selection' Science 189(4206) (12 September 1975): 870-871. Michael J. Wade, 'Group Selection among Labaratory Populations of Tribolium' Proceedings of the National Academy of Seiences 73(12) (December 1976): 4604-07; Michael J. Wade and David E. McCauley, 'Group Selection: The Phenotypic and Genotypic Differentiation of Small Populations' Evolution 34(4) (July 1980): 799-812; Robert Boyd and Peter J. Richerson, 'Group Selection among Alternative Evolutionarily Stahle Strategies' Journal of Theoretical Biology 145(3)

3. Levels of Selection

27

termed a "low migration group" in order to differentiate it from a kin-group. In order to preserve the possibilities of other factors leading to group selection, however, this type of vehicle will simply be termed the group. lt is a remarkable conclusion of population genetics that the Iifting of F within a group occurs relatively automatically with the restriction of immigration, and can be shown to be dependent on the number of migrants rather than on the size of the group. 84 Depending on the immigration and emigration pattems,85 such as the distance travelled by a typical rnigrant, and the geographical arrangement of the groups, F may decline gradually over neighbouring groups, rather than sinking rapidly at the group border.

As with kin selection, 'altruistic' traits will only be selected when

FK/k > 1.86 The reduction of the probability of a sudden extinction seems the

most likely manner of achieving a high K, as in the model developed by Eshel,87 but an increase in the rate of emission of migrants provides an alternative route. 88 Yet despite the inherent logic of this approach, and the many models of group selection that have been formulated, group selectionists are generally looked at askance by their colleagues. 89 lt may be that empirical evidence for

(1990): 331-342; David Sloan Wilson, 'Weak Altruism, Strong Group Selection' Oikos 59(1) (1990): 135-140. 84 Rarnilton demonstrates this with the aid of "island" and "stepping-stone" models (Hamilton, 'Innate Social Aptitudes', pp. 141-142). See also Motoo Kimura and G.H. Weiss, 'The Stepping Stone Model of Population Structure and the Decrease of Genetic Correlation with Distance' Genelies 49 (1964): 561-576; Eshel, 'Neighbor Effect', esp. pp. 274-275. 85 For discussions of factors influencing emigration see William D. Rarnilton and Robert M. May, 'Dispersal in Stahle Habitats' Nature 269 (October 1977): 578-581, esp. p. 580. Peck has shown that mechanisms for outsider exclusion may evolve in a wide variety of circumstances because of the reduction in competition for limited resources that thereby results (Joel R. Peck, 'The Evolution of Outsider Exclusion' Journal of Theoretical Biology 142(4) (22 February 1990): 565-571, esp. pp. 565-566). 86

group.

It should be noted that K represents the net benefit to all the members of the

87

Eshel, 'Neighbor Effect', p. 251.

811

Hamilton, 'lnnate Social Aptitudes', p. 142.

Dawkins indeed tries to reinterpret Hamilton: having quoted the frrst part of the last passage quoted above, he comments that Rarnilton "at frrst reading might be thought to be endorsing the lumping of kin and group selection. To avoid confusion I quote him 89

28

II. The Elements of Evolution

traits that evolved through group selection are necessary to finally settle the issue, a theme retumed to below. 4. Other Replicators and Vehicles The use of the Price-Hamilton analysis has allowed the depiction of selection as acting on a variety of vehicles, with the strength of selection resulting from the characteristics of the particular case, rather than being stable and predictable a priori. Although the theoretical framework is very general the discussion has been limited to one form of replicator, the genetic replicators that are generally termed genes, and three vehicles: genets, kin-groups, and groups. The result of selection is to create adaptations 'for' these vehicles, which ultimately are 'for' the genetic replicators within them, and these adaptations are instantiated through mechanisms located within organisms. Organisms thus have a special role in this approach, as they are the entity within which genetic replicators exert their biochemical influence which eventually results, after an enormously ccimplex developmental process, in the morphological and behavioural traits that we observe. This analysis has been restricted to one replicator and three vehicles because they all have direct relevance to the principal theme of this book: the explanation of human behaviour. There are other candidates for replicators and vehicles, however, and they will be briefly considered here. One proposal for a replicator that has awakened considerable interest outside biology is Dawkins' concept of a 'meme': ideas, tunes, pithy sayings and so on, that are copied arnong communicating brains.90 Dawkins hirnself has since realised, however, that there are differences from genetic replicators which "may prove sufficient to render the analogy with genetic natural selection worthless or even positively misleading". 91 Another contender as a possible replicator is the species, an hypothesis advanced for exarnple by Alexander and Borgia.92 The postulation of species

in full" (Dawkins, 'Replicators and Vehicles', p. 57). In the light of the fuller text, together with Hamilton's other reported views, there can be no doubt that Hamilton does indeed endorse "the lumping of kin and group selection". 90

The concept was originally presented in Dawkins, Selfish Gene, pp. 192-201.

91

Dawkins, Extended Phenotype, p. 112; see generally pp. 109-112.

Richard D. Alexander and Gerald Borgia, 'Group Selection, Altruism, and the Levels of Organisation of Life' Annual Review of Ecology and Systematics 9 92

4. Other Replicators and Vehicles

29

as replicators faces the difficult problern that they are not fundamental: Iike memes they are ultimately dependent on genetic replicators for their existence. The 'copying' of species does not differ fundamentally from the 'copying' of groups, and it thus appears preferable to interpret species as forming another Ievel of vehicle, operating over a broad set of genetic replicators, rather than over the gene pool belonging to any one lineage. This view of species selection as a higher Ievel of group selection is that used by Alexander and Borgia, in their analysis of the operation and implications of species selection: Species can co-exist, "poised" to replace one another, without losing their differences through arnalgamation. Indeed they can continue to diverge, and they can even cause one another' s extinction. One implication is that while ecological communities may often be significantly affected by differential extinction of species, species are not necessarily likely to have been greatly influenced by differential extinction of populations or demes (see 81). Another isthat conspecific populations that behave toward one another as if they were different species - maintaining separate territories, discouraging movement of individuals between groups, displaying intergroup aggression, and especially showing efforts to extinguish and replace one another - are thereby enhancing the likelihood of significant group selection, or indicating its importance in the past. Units or groups such as species, then, may be established through individual or genic selection, yet persist or fail as a result of competition with other species hence, through a kind of group selection.93

Species thus form an additional Ievel of vehicle to the three considered above, and it has already implicitly been used in the "parasite pressure" explanation of sex, where those multicellular species that failed to evolve sexual reproduction were less successful in ensuring the survival of their genetic replicators in the competition with sexual species due to parasitism. It appears likely that species selection is responsible for the appearance of other fundamental characteristics, such as "Cope's rule" of increasing body size.94

(1978): 449-474, p. 456 [hereafter Alexander and Borgia, 'Levels of Organisation']. This was the subject of a continuing controversy with Dawkins; see e.g., Dawkins, Selfish Gene, p. 11; Dawkins, Extended Phenotype, p. 108.

93 Alexander and Borgia, 'Levels of Organisation', p. 455-456. [81 = David Sloan Wilson 'Evolution on the Level of Communities' Science 192 (1976): 1358-60].

94 This possibility was explicitly recognised by Williams, in a work which is widely regarded as demonstrating the irrelevance of higher Ievels of selection: "It may be that at any given moment during the tertiary, most of the horse populations were evolving a smaller size. To account for the trend towards !arger size it is merely necessary to

30

li. The Elements of Evolution

The extremely long time period over which this selection operates, together with the fact that it affects replicator survival by eliminating !arge groups of genetic replicators en masse, would appear, however, to Iimit the consequences of species selection to such fundamental characteristics such as sex or size. Thus although the species vehicle appears to exist and may be of substantial importance in specific spheres, the focus on individual behaviour has led to a concentration on vehicles below the Ievel of the species. A further set of entities that could be classed as replicators or vehicles occurs at the other scale of the hierarchy of life: within the genome. A genome is the entire collection of genetic replicators contained in an organism. In sexual species the effect of meiosis is to create a unique combination of genetic replicators in each individual, so that the whole genomeisnot the active germline replicator, but rather those particular elements that are copied into the following generation. The "gavotte of chromosomes", to use Hamilton's famous phrase,95 appears generally to ensure that each of the genetic replicators within the non-sex chromosomes (autosomes) faces the same chance of being present in the next generation, and in general seems very successful in doing so. The unity thereby achieved in the genome is threatened, however, by forms that advance their own 'interests' at the expense of their competitors. Until recently it was widely believed that: Genes that favor themselves at the expense of all other genes in the genome (outlaw genes) are likely to have their effects nullified, at the very least to the extent that they are outnumbered by the other genes in the genome. 96

make the additional assumption that group selection favoured such a tendency. Thus, while only a minority of the populations may have been evolving a larger size, it could have been this minority that gave rise to most of the populations of a million years later" (Williams, Adaptation and Natural Selection, p. 99). See also Stephen Jay Gould 'The Promise of Paleobiology as a Nomothetic, Evolutionary Discipline' Paleobiology 6 (1980): 96-118; Dawkins, Extended Phenotype, pp. 100-105. 95 William D. Hamilton, 'Gambiers since Life Began: Barnacles, Aphids, Elms' Quarterly Review of Biology 50(2) (June 1975): 175-180, p. 175 [hereafter Hamilton, 'Gambiers']. 96

Alexander and Borgia, 'Levels of Organisation', p. 458.

4. Other Replicators and Yehicles

31

Through such a "parliament of genes"97 it was assumed that the effect of such "outlaw genes" would be minimised, and the genome (and hence the genet) would provide the first significant Ievel of selection. It is becoming increasingly clear that the possibility of selection inside the genome can not be so lightly dismissed. Even within the cell nucleus theoretical analyses demoostrate the dramatic effects that "driving" X and Y chromosomes could have on a species.98 A further consideration is the existence of genetic replicators that are not in the nucleus and hence exist independently of the chromosomes, and which have been termed "cytoplasmic genes". 99 An interesting example of such cytoplasmic genes are the bacterial plasmids, rings of DNA that exist outside the chromosomes. 100 Eberhard has, for example, concluded that:

97 The term was coined by Leigh, (Egbert Giles Leigh, Jr., 'How Does Group Selection Reconcile Individual Advantage with the Good of the Group?' Proceedings of the National Academy of Seiences 74(10) (October 1977): 4542-46, p. 4543). Ironically analysis in terms of collective action by self-interested actors would have given little ground for confidence in the automatic achievement of the collective good. See e.g., Mancur Olson, Jr., The Logic of Collective Action: Public Goods and the Theory of Groups, Harvard Economic Studies Yol. 124 (Cambridge, MA: Harvard University Press, 1965), esp. pp. 22-52 [hereafter Olson, Logic]. 98 See William D. Hamilton, 'Extraordinary Sex Ratios' Science 156 (28 April1967): 477-488, p. 478 [hereafter Harnilton, 'Extraordinary Sex Ratios']. Hamilton suggests that the potentially catastrophic consequences of a driving Y chromosome would Iead to selection for modifier genes that "would slow down (although it would never arrest) the spread of the Y mutant and, at the same time, would cover up its effect." (p. 479). This indicates that only when an outlaw causes extreme consequences would counterselection be effective, but that in more normal cases, such as the driving X chromosome, the interest of the collective can be expected to suffer. For a more general analysis see Ian M. Hastings, 'Population Genetic Aspects of Deleterious Cytoplasmic Genomesand their Effect on the Evolution of Sexual Reproduction' Genetic Research 59 (June 1992): 215-225; 99 "We will call genes that exist independently of the chromosomes, and that replicate by an independent process at least part of the time cytoplasmic genes. These include plasmids, organelle genes, heritable viral factors, heritable endosymbionts, cytoplasmic genetic factors of undetermined location, preformed structures, and episomes to the extent they reproduce independently of the chromosomes. Leda Cosmides and John Tooby, 'Cytoplasmic lnheritance and Intragenomic Conflict' Journal ofTheoretical Biology 89(1) (7 March 1981): 83-129, p. 83, fn. : · ...-.. :.. ·~EN~ .POOLO';· . j:-::':··

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Stringer's illustration reproduced in fig. 4.5, by portraying brain weight versus body weight for a range of higher primates including man. 77 Reprinted, with permission from Academic Press and the author, from Chris Stringer, 'Human Evolution and Biological Adaptation in the Pleistocene' in Robert Foley (ed.), Hominid Evolution and Community Ecology: Prehistoric Human Adaptation in Biological Perspective, pp. 55-83, Studies in Archaeology Series (London: Academic

100

IV. Evolution and the Human Psyche

While not of itself an explanatory structure, the firm empirical base provided by fossils allows the history of encephalisation to be used to discriminate between hypotheses, and Wynn has made a significant contribution by utilising it to dismiss the theories positing that tool use led to hominid intelligence: 78 I think it fair to eliminate from consideration the simple scenario in which ability to make better and better tools selected for human intelligence. At almost no point in hominid evolution was there even a provocative correlation. The earliest known hominids, Australopithecus afarensis, had a brain !arger than an ape's of equivalent size, but as far as we know, no greater reliance on tools. Early Homo at 2 Ma had a much more 'encephalized' brain. but the tools and even the context of use were not beyond the capacity of modern apes. Homo erectus did possess technology that was outside the range of ape behaviour, but by this time, 1.5 Ma, much of the encephalization of the Homo line had already occurred. In sum, most of the evolution of the human brain, the presumed anatomy of intelligence, had occurred prior to any evidence for technological sophistication and, as a consequence, it appears unlikely that technology itself played a central roJe in the evolution of this impressive human ability. 79

Press, 1984), fig. 3.3 p. 76 [hereafter Stringer, 'Adaptation in the Pleistocene']. The original caption continues: "the least squares regression line shown is the regression for endocranial volume to age, but the regression for age to volume and the reduced major axis were also calculated. They have not been plotted here as there is little difference between them and the line shown. The equation for the regression of age to log volume is y = -0.50x + 2.66, and the reduced major axis equation is y = -0.45[x) + 2.62." 78 Washbum has, for example, claimed that "the structure of modern man must be the result of the change in the terms of natural selection that came with the tool-using way of life" (Sherwood L. Washbum, 'Tools and Human Evolution' Scientific American 203(3) (September 1960): 63-75, p. 63). Foramore recent model in which tool use and language interact see Sue Taylor Parkerand Kathleen Rita Gibson, 'A Developmental Model for the Evolution of Language and Intelligence in Early Hominids' Behavioral and Brain Seiences 2(3) (September 1979): 367-408. 79 Thomas Wynn, 'Tools and the Evolution of Human Intelligence' in Richard W. Byme and Andrew Whiten (eds.), Machiavellian lntelligence: Social Expertise and the Evolution of lntellect in Monkeys, Apes, and Humans, pp. 271-284 (Oxford: Clarendon Press, 1988), p. 283 [hereafter Wynn, 'Tools'; emphasis in the original]. See also Thomas Wynn, The Evolution of Spatial Competence, Illinois Studies in Anthropology, No. 17 (Urbana, IL: University of Illinois Press, 1989), p. 98; Thomas Wynn, 'Archaeological Evidence for Modem Intelligence' in Robert A. Foley (ed.), The Origins of Human Behaviour, pp. 52-66, One World Archaeology Series, Vol. 19 (London: Unwin Hyman, 1991).

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b) The Capacity for Sociality

That man is social animal is an observable fact: humans everywhere live in groups, which range in size from small bands and tribes to states comprising hundreds of millions of inhabitants. When such groups disintegrale the constituent individuals do not then live on their own or with their immediate families, but in sections of the original group which may then become independent in their own right. The size and cooperative division of labour achieved by humans is one of our distinguishing characteristics, found in no other species where each of the members potentially reproduces sexually. 80 Such complex sociality is not an inherent prediction of evolutionary theory: in contrast the expectation that selection will generally act most strongly on the lower Ievels of vehicle indicates that organisms will only live in groups in exceptional circumstances. 81

°

8 For a discussion of the four living forms (clones, eusocial insects, nonhuman mammals, and humans) that have achieved "ultrasociality" see Alexander, Moral Systems, pp. 65-69. 81 For a general analysis of optimal group size, see James L. Boone, 'Competition, Conflict, and Development of Social Hierarchies' in Eric Aiden Smith and Bruce Winterhaider (eds.), Evolutionary Ecology and Human Behavior, pp. 301-338, Foundations ofHuman Behavior Series (Hawthome, NY: Aldine de Gruyter, 1993), esp. pp. 302-315 [hereafter Boone, 'Social Hierarchies'J. Campbell argues that "1. Human urban social complexity has been made possible by social evolution rather than biological evolution. 2. This social evolution has had to counter individual selfish tendencies which biological evolution has continued to select as a result of the genetic competition among the cooperators" (Donald T. Campbell, 'On the Conflicts between Biological and Social Evolution and Between Psychology and Moral Tradition' American Psychologist 30(12) (December 1975): 1103-1126, p. 1115 [original italicised; hereafter Campbell, 'Conflicts'J). This then Ieads Campbell to ascribe "a social functionality and psychological validity to concepts such as temptation and original sin due to human carnal, animal nature" (ibid., p. 1116), and to create a "two system model" where "Social System Preaching" pulls individual behaviour from the "Biological Optimum" to a "BioSocial Optimum" (ibid., Figure 1 and pp. 1117-20). This is a relatively sophisticated example of a confusion between "social" (or cultural) and "biological" evolution that is prevalent in social-scientific discussions of biological theory. Campbell's points 1. and 2. may weil be correct, in that social institutions such as laws are necessary for the existence of human societies, and that these often counter "individual selfish tendencies". This is not an explanation of sociality, however: human psychological characteristics mean that individuals are in general prepared to obey such laws, and so on. It is the existence of these psychological traits that must be explained in terrns of the advantage they provided to their vehicles in the environment of evolutionary adaptedness.

102

IV. Evolution and the Human Psyche

Alexande~2 has proposed that three generat explanations make it advan-

tageaus for animals to live in groups: (1) lowering of susceptibility to predation through aggressive group defence or "selfish herd" effects;83 (2) cooperative hunting; and (3) localisation of resources such as food or sleeping sites that force individuals to remain together. Of these causes, (3) may lead to group living in the sense of close spatial proximity, but will not of itself Iead to group cooperation and complex social organisation. 84 Factor (2) is a powerful cause of cooperative behaviour, and appears primarily responsible for the complex sociality observable among canines, felines, cetaceans, group-hunting fish, and group-fishing pelicans, and for birds which are dependent on !arge scattered food sources such as foraging vultures and sandpipers.85 Hunting was probably also the cause of early human groupings, even though gathering may have provided the majority of the food actually consumed. Examination of non-human group hunters indicates that the degree of cooperation achieved can be quite high, 86 but that there is a low

82 These categories and their relation to human sociality were flrst proposed in Alexander, 'Evolutionary Philosophy of Man', p. 115. Later expositians include Richard D. Alexander, 'The Evolution of Social Behavior' Annual Review of Ecology and Systematics 5 (1974): 325-383, pp. 329-331 [hereafter Alexander, 'Evolution of Social Behavior']; Richard D. Alexander, 'The Search for a General Theory of Behavior' Behavioral Science 20 (1975): 77-100 [hereafter Alexander, 'General Theory of Behaviour']; Alexander, Human Affairs, pp. 58-65; Alexander, Moral Systems, pp. 79-81; Richard D. Alexander, 'Evolution of the Human Psyche' in Paul Mellars and Chris Stringer (eds.), The Human Revolution: Behavioural and Biological Perspectives on the Origins of Modem Humans, pp. 455-513 (Princeton, NJ: Princeton University Press, 1989), pp. 465-469 [hereafter Alexander, 'Human Psyche'].

83 The terrn "selflsh herd" was coined by Rarnilton (William D. Hamilton, 'Geometry for the Selflsh Herd' Journal ofTheoretical Biology 31 (1971): 295-311), and refers to group behaviour which is not explicitly cooperative, but rather the result of individually "selfl.sh" actions. 84 Kummer notes, for example, that although Hamadryas baboons live during the day in "small dispersed social units, the scarceness of groves or cliffs for sleeping requires exactly the opposite, i.e. !arge concentrations of animals in a few spots" (Hans Kummer, Social Organization of Hamadryas Baboons: A Field Study, Bibliotheca Primatologica, No. 6 (Basel: S. Karger, 1968), p. 155).

85

See Alexander, Human Affairs, p. 64; Alexander, 'Human Psyche', p. 467.

See e.g., L. David Mech, The Wolf: The Ecology and Behavior of an Endangered Species, [1970] rev. ed. (Minneapolis, MN: University of Minnesota Press, 1981), pp. 193-245. 86

4. Accounting for Hominid Cognitive Development

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upper size-limit. This is because the marginal benefit from increments in the size of such groups drops rapidly, as the size needed to locate and obtain the largest type of game or the most dispersed food source is exceeded.87 lt is thus possible to conceive of groups of tens of hominids being formed because of cooperative hunting, and a substantial amount of evidence suggests that this may have indeed been the factor which initiated hominid sociality. 88 At some stagein our evolutionary history, however, our ancestors acquired the capacity to live in social groups comprising hundreds, thousands, and millions of individuals, and the only adequate functional explanation is thus the benefit gained from factor (1). It is this protection from 'predation' that forms the subject of the next subsection. c) The "Balance of Power" Hypothesis

The previous two subsections have shown that an adequate theory of hominid development must account for a very rapid expansion in intelligence as estimated by encephalisation, and increases in the potential size of cooperative groups that did not result from either group hunting or localisation of resources. An elegant explanation termed the "balance of power" hypothesis by Alexande~9 and the "autocatalysis model" by Wilson90 links all three See generally Craig Packer and Lore Ruttan, 'The Evolution of Cooperative Hunting' American Naturalisr132(2) (August 1988): 159-198, esp. pp. 161-169; Packer, 'Evolution of Reciprocity'. 87

88 Although this was once a widely accepted account of early horninid social organisation, a recent review notes that it "has since fallen from favor for cultural reasons (ferninist revisionism) and because quantitative analysis of certain modern hunter-gatherer diets indicates that plant foods provide the majority of the calories" (Tooby and Devore, 'Strategie Modelling', p. 222). Having concluded a review of alternative hypotheses Tooby and DeVore conclude that it was the most likely process that began the hominid evolutionary developments, explaining: male parental investrnent, sexual dimorphism, male coalitions, social exchange, sexual division of labour, pongidhominid divergence, and geographical distribution (ibid., pp. 222-226). 89 Alexander, 'Evolutionary Philosophy of Man', pp. 115-117; Alexander, 'Evolution of Social Behavior', p. 335; Alexander, 'General Theory of Behaviour', pp. 93-95; Alexander and Borgia, 'Levels of Organisation', p. 470; Alexander, Human Affairs, p. 220-233; Richard D. Alexander and Kathenne M. Noonan, 'Concealment of Ovulation, Parental Care, and Human Social Evolution' in Napoleon A. Chagnon and William G. Irons (eds.), Evolutionary Biology and Human Social Behavior: An Anthropological Perspective, pp. 436-453 (North Scituate, MA: Duxbury Press, 1979), pp. 439-441

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IV. Evolution and the Human Psyche

elements together: the 'predators' inducing sophisticated group behaviour were other groups of humans, and the competitive process led to an evolutionary arms race for cognitive faculties that increased effectiveness in between-group aggression: This proposition is immediately satisfying, for it (perhaps alone) can explain any size of group (as parts of balance-of-power races). lt accords with all of recorded human history; it is consistent with the fact that humans alone play competitively groupagainst-group (and indeed they do this on a !arge and complex scale) - if play is seen broadly, as practice. And it accords with the ecological dominance of the human species and the disappearance of all its close relatives. 91

This hypothesis has a long and 'punctuated' history in the literature: Darwin outlined the essential elements in 1871;92 then followed a period of 'stasis' until shortly after the Second World War;93 then a phase of relatively rapid growth emerged after the late 1960s.94 It is an intrinsically attractive [hereafter Alexander and Noonan, 'Concealment of Ovulation'); Alexander, Moral Systems, pp. 79-81; Alexander, 'Human Psyche', pp. 469-477. 90 Edward 0. Wilson, 'The Queerness of Social Evolution' Bulletin of the Entomological Society of America 19 (1972): 20-22, p. 22; Wilson, Sociobiology, pp. 567-575. 91

Alexander, 'Human Psyche', p. 469 [emphasis in the original].

Darwin, Descent of Man, passim. Pitt in bis review of the development of this theory (Roger Pitt, 'Warfare and Hominid Brain Evolution' Journal of Theoretical Biology 72 (1978): 551-575, p. 552 [hereafter Pitt, 'Brain Evolution')) serious1y underestimates Darwin' s contribution, claiming that Darwin was "referring to an improvement in human brainpower, rather than to the creation of it" (p. 555). lt should be clear from the subsection on encephalisation that Darwin was correct not to "contemplate warfare as the creator of the novel substance of the human brain", as there was no such "novel substance". Pitt further asserts that Darwin (and Keith) "plainly meant warfare in historical or prehistorical times" (p. 552) apparently relying on the Origin of Species and "the Statements of Darwin that are mentioned by Keith and Wilson" (p. 555). In contrast Darwin's Descent of Man abounds with statements of the type "when two tribes of primeval man, Iiving in the same country, came into competition" (Part I, p. 162); "we might feel almost sure . .. that the law of battle bad prevailed with man during the early stages of bis deve1opment" (Part II, p. 324). 92

93 Sir Arthur Keith, A New Theory of Human Evolution [1949) (Gloucester, MA: Peter Smith, 1968) esp. pp. 37-63. 94 See e.g., William D. Hamilton, 'Selection of Selfish and Altruistic Behaviour in Some Extreme Models' in J.F. Eisenberg and W.S. Dillon (eds.), Man and Beast: Comparative Social Behavior, pp. 57-91 (Washington, DC: Smithsonian Press, 1971), esp. pp. 78-81; Richard D. Alexander and D.W. Tinkle, 'A Comparative Book Review

4. Accounting for Horninid Cognitive Development

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explanation, as by positing an "evolutionary arms race" 95 it is possible to explain the sustained selection for increased cognitive abilities and hence the increased encephalisation, tagether with the particular characteristics of human sociality. The importance of this dynamic element can be clearly perceived by imagining that relatively static forces, such as more effective hunting of large animals or defence against non-human predators had caused human sociality. The impetus to cognitive development could have been substantial, but would be expected to have relatively rapidly reached a new equilibrium. Inter-species arms races are run in evolutionary time, so that the processes of adaptation and counter-adaptation such as those between cuckoos and their hosts discussed above proceed relatively slowly. In contrast, inter-group aggression concems vehicles that share the same gene-pool, so that an explosive arms race may result resembling the process of "runaway sexual selection" recognised by Fisher: Plumage developments in the male, and sexual preference for such developments in the female, must advance together, and so long as the process is unchecked by severe counterselection, will advance with ever-increasing speed. In the total absence of such checks, it is easy to see that the speed of development will be proportional to the development already attained, which will therefore increase with time exponentially, or in geometric progression. 96

of On Aggression by Komad Lorenz and The Territorial Initiative by Robert Ardrey' Bioscience 18 (1968): 245-248, pp. 246-247; Robert S. Bigelow, The Dawn Warriors: Man's Evolution Toward Peace (Boston: Little Brown, 1969), esp. pp. 3-20 [hereafter Bigelow, Dawn Warriors]; Robert S. Bigelow, 'The Evolution of Cooperation, Aggression, and Self Control' Nebraska Symposium on Motivation 20 (1972): 1-57 [hereafter Bigelow, 'Evolution of Cooperation' ]; Pouwel S1urink, Ecological Dominance and the Final Sprint in Hominid Evolution (Unpublished Paper, University of Nijmegen, The Netherlands, 1993) [hereafter Slurink, Ecological Dominance]. See also Robert Ardrey, African Genesis: A Personallnvestigation into the Anima[ Origins and Nature of Man (New York: Atheneum, 1961); Robert Ardrey, The Territorial Imperative: A Personal Enquiry into the Anima[ Origins of Property and Nations (New York: Atheneum, 1966); Robert Ardrey, The Hunting Hypothesis (New York: Atheneum, 1976). 95 See generally Dawkins and Krebs, 'Arms Races' . For expositions and intriguing examples see Dawkins, Extended Phenotype, pp. 55-80; Dawkins, Blind Watchmaker, pp. 178-193. 96 Fisher, Genetical Theory, p. 58. A mathematical treatment of this rather comp1ex dynamic process in terms of "polygenes" is provided by Lande (Russen Lande, 'Models of Speciation by Sexual Selection of Polygenie Traits' Proceedings National Academy of Seiences 78 (1978): 3721-5; Russen Lande, 'Sexual Dimorphism, Sexual Selection,

106

IV. Evolution and the Human Psyche

In the case of hominids the ecological dominance that also accompanied this increase in intelligence meant that other selective agents such as food shortages or predation were relatively unimportant, leaving a relatively greater role for the balance of power process. Even such a "runaway" process can not continue indefinitely, however, and it appears that the 'autocatalytic' phase of an increasing rate of change in encephalisation through time broke off in the late Pleistocene, after which period the increase in brain sizes ended, and the absolute brain size may even have declined. 97 Such reductions or even reversals in the phylogenetic rate of brain growth may have resulted from a darnpening of the 'explosive' character of the selection resulting from the balance of power process, but the inter-group conflicts themselves continued. From the earliest historical periods war has played a major role in relations between groups,98 and in contrast to "the central myth of modern anthropology",99 warfare is prevalent in hunter-gatherer

and Adaptation in Polygenie Characters' Evolution 34 (1980): 292-305). Fora possible natural example see Malte Andersson, 'Female Choice Selects for Extreme Tail Length in a Widowbird' Nature 299 (28 October 1982): 818-820. For alternative models of sexual selection see Alan Grafen, 'Sexual Selection Unhandicapped by the Fisher Process' Journal ofTheoretical Biology 144(4) (21 June 1990): 473-516; Alan Grafen, 'Biological Signals as Handicaps' Journal ofTheoretical Biology 144(4) (21 June 1990): 517-546. 97 Stringer concludes his analysis of the data and regression equation presented in fig. 4.5 with the comment "from this data,' the autocatalytic model of endocranial volume increase seems most appropriate since there is an increasing rate of change until the late Pleistocene, when endocranial capacity values stabilize or even decline" (Stringer, 'Adaptation in the Pleistocene' , p. 78). "Autocatalytic" appears tobe used by Stringer solely as a description of the nonlinear character of this relationship, e.g., "an autocatalytic model of change, where the rate of change accelerates through time" (ibid., p. 77). This is compared to the linear relationship postulated by some researchers in this field, or the punctuated equilibria model of "a stepped pattem of brain increase, followed by stasis" (ibid.). This statistical observation of autocatalysis contrasts sharply with its deduction from the balance of power model, and appears to be another example of the compartmentalisation of this theory discussed below.

98 See e.g., Colin McEvedy, The Penguin Atlas of Ancient History (Harmondsworth, Middlesex: Penguin, 1967), passim. McEvedy remarks in an aside that "there is little doubt that [Homo sapiens] was quicker thinking than the primitives and demonstrated his superiority by hunting them down. If the evidence for man' s descent is scanty, we can thank our ancestors who probably ate most of it" (p. 16). 99 Alexander, Moral Systems, p. 127. Alexander characterises the myth as saying "that humans lived 99% of their existence as small, peaceful, nomadic, separated family

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societies. 100 Cameiro has made a dramatic break with this myth in his explicit use of inter-group aggression as a foundation for his "circumscription theory" of social evolution: A close exarnination of history indicates that only a coercive theory can account for the rise of the state. Force, and not enlightened self-interest, is the mechanism by which political evolution has led, step by step, from autonomous villages to the state. 101

The mechanism of warfare in combination with the conditions of "environmental and social conscription" has proved a powerful general theory for explaining social and political development. 102 1t should not need to be stressed that war

groups of hunter-gatherers whose life was almost solely made up of cooperation with scarcely any competitiveness, aggression, or nastiness of any kind" (ibid.). 100 Ernher has conducted a statistical investigation of a world-wide sample of 50 hunter-gatherer societies and concluded that "64 per cent had warfare occurring at least once every two years, 26 per cent had warfare somewhat less often, and only 10 per cent (including the !Kung) were rated as having no or rare warfare" (Carol R. Ember, 'Myths about Hunter-Gatherers' Ethnology 17 (1978): 439-448, p. 443). Chagnon has concluded on the basis of detailed analysis of the Yanomamö that "nearly 70% of all individuals (males and females) age 40 or older have lost at least one close genetic kin due to violence, and most (57%) have lost two or more." (Napoleon A. Chagnon, 'Life Histories, Blood Revenge, and Warfare in a Tribai Population' Science 239 (February 1988): 985-992, p. 989). He suspects "that the amount of violence in Y anomamö culture would not be atypical if we had comparative measures of precontact violence in other similar tribes while still independent of colonial nation states" (ibid.). 101 Robert L. Carneiro, 'A Theory of the Origin of the State' Science 169 (21 August 1970): 733-38, p. 734. Carneiro's later work on this theme include Robert L. Carneiro, 'Political Expansion as an Expression of the Principle of Competitive Exclusion' in Ronald Cohen and Elman R. Service (eds.), Origins ofthe State: The Anthropology of Political Evolution, pp. 205-223 (Philadelphia: Institute for the Study of Human Issues, 1978); Robert L. Carneiro, 'Further Reflections on Resource Concentration and Its RoJe in the Rise of the State' in Linda Manzanilla (ed.), Studies in the Neolithic and Urban Revolutions, The V. Gordon Childe Colloquium; International Series 349, pp. 245-260 (Mexico: Bar, 1987); Robert L. Carneiro, 'The Circumscription Theory: Challenge and Response' American Behavioral Scientist 31(4) (March 1988): 497-511.

102 For a recent discussion of the circumscription and competing theories see Robert B. Graber and Paul B. Roscoe, 'Introduction: Circumscription and the Evolution of Society' American Behavioral Scientist 31(4) (March/April1988): 405-415, and the other contributions to this special issue. See also David Webster, 'Warfare and the Evolution of the State: A Reconsideration' American Antiquity 40(4) (October 1975): 464-70; Henry T. Wright, 'Recent Research on the Origin of the State' Annual Review of Anthropology Bemard J. Siegel (ed.), 6 (1977): 379-97; Elman R. Service, 'Classical and

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and related activities continue to characterise human inter-group behaviour, 103 and the unceasing importance of balance of power processes is witnessed by the continuing use of the term in acadernic and practical interpretations of international affairs. 104 The balance of power hypothesis thus provides a clear and easily understood explanation for both the emergence of human sociality and the rapidity of horninid encephalisation. Among one group of researchers, primarily associated with biological approaches to human behaviour, the hypothesis has been largely accepted and attention has shifted to the acquisition of relevant evidence, 105 the development of subsidiary hypotheses, 106 and other themes dependent on Modem Theories of the Origins of Govemment' in Ronald Cohen and Elman R. Service (eds.), Origins of the State: The Anthropology of Political Evolution, pp. 21-34 (Philadelphia: Institute for the Study of Human Issues, 1978); Maleolm C. Webb, 'The State of the Art on State Origins?' Reviews in Anthropology 11(4) (Fall 1984): 270-281; Kent V. Flannery, 'The Cultural Evolution of Civilisations' Annual Review of Ecology and Systematics 3 (1972): 399-426; George R. Milner, Eve Anderson, and Virginia G. Smith, 'Warfare in Late Prehistoric West-Centtal Illinois' American Antiquity 56(4) (1991): 581-603. 103 See e.g., Melvin Small and J. David Singer, Reson to Arms (Beverly Hills, CA: Sage, 1982); Bruce Bueno de Mesquita, The War Trap (New Haven, CT: Yale University Press, 1981), [hereafter Bueno de Mesquita, War Trap], esp. pp. 98-99; Paul M. Kennedy, The Rise and Fall of the Great Powers: Economic Change and Military Conflict from I500 to 2000 (New York: Random House, 1987), passim. For a discussion of genocide see Jared Diamond, The Rise and Fall of the Third Chimpanzee (London: Vintage, 1991), pp. 250-266, esp. the figs. pp. 256-258 [hereafter Diarnond, Third Chimpanzee ]. 104 See e.g., Kenneth N. Waltz, Theory of International Politics (Reading, MA: Addison Wesley, 1983), esp. pp. 102-128 [hereafter Waltz, International Politics]; Hans J. Morgenthau, Politics among Nations: The Struggle for Power and Peace, 2nd ed. rev. and enlarged (New York: Alfred A. Knopf, 1954), pp. 155-204 [hereafter Morgenthau, Politics among Nations]; Michael Howard, 'Military Power and International Order' International Affairs (July 1964): 397-408; Hedley Bull, The Anarchical Society: A Study of Order in World Politics (London: Macmillan, 1977).

105 Strate, for exarnple, investigated cross-cultural variations in political organisation in response to extemal aggression (John Martin Strate, An Evolutionary View of Political Culture (Doctoral Dissertation, University of Michigan: University Microfilms, 1982), esp. pp. 263-351).

106 Alexander and Noonan, for exarnple, conclude that parental care would have increased in value because of increased inter-group and intra-group competition, and exarnine the concealment of ovulation by human females from this perspective (Alexander and Noonan, 'Concealment of Ovulation', pp. 440 f f). Slurink suggests that

4. Accounting for Hominid Cognitive Development

109

a general acceptance of inter-group aggression as a dominant influence on hominid evolution. 107 Such research based on an explicit recognition of the importance of the balance of power hypothesis is, however, a small proportion ofthat concerned with the phylogenetic trajectory tak:en by hominids in general, and the emergence of human cognitive and behavioural characteristics in particular. Given the undoubted importance of the hypothesis, should it be correct, to an immense range of subjects from paleoanthropology to international relations, the widespread failure to acknowledge it would mak:e a fascinating study in intellectual history in its own right. 108 By normal scientific standards such a

the discovery of ftre may have been the catalyst for the emergence of ecological dominance and runaway selection (Slurink, Ecological Dominance, esp. pp. 8-12). 107 See e.g., William H. Durham, 'Resource Competition and Human Aggression, Part 1: A Review of Primitive War' Quarterly Review of Biology 51 (September 1976): 385-415, esp. p. 391; Gerald Borgia, 'Human Aggression as a Biological Adaptation' in Joan S. Lockard (ed.), The Evolution of Human Social Behavior, pp. 165-191 (New York: Elsevier, 1980), pp. 178-179; R. Paul Shaw, 'Humanity's Propensity for Warfare: A Sociobiological Perspective' Canadian Review of Sociology and Anthropology 22(2) (1985): 158-183, p. 166 ff. ; R. Paul Shaw and Yuwa Wong, 'Ethnic Mobilization and the Seeds of Warfare: An Evolutionary Perspective' International Studies Quarterly 31 (1987): 5-31, pp. 9 ff.; Harnilton, 'Innate Social Aptitudes', pp. 141-150; Fred H. Willhoite, Jr., 'Primates and Political Authority: A Biobehavioral Perspective' American Political Science Review 70(4) (December 1976): 1110-1126, pp. 1118-1123; Fred H. Willhoite, Jr., 'Evolution and Collective Intolerance' Journal of Politics 39 (1977): 667-684, pp. 678-682; Fred H. Willhoite, Jr., 'Rank and Reciprocity: Speculations on Human Emotions and Political Life' in Elliott White (ed.), Sociobiology and Human Politics, pp. 239-258 (Lexington, MA: Lexington Books, 1981), esp. pp. 251-252; Irons, 'Broader Rather Than Narrower', pp. 364-369; Johanson and Shreeve, Lucy's Child, pp. 276-280; Laura L. Betzig, Despotism and Differential Reproduction: A Darwinian View of History, Foundations of Human Behavior Series (Hawthome, NY: Aldine de Gruyter, 1986) [hereafter Betzig, Despotism]; Michael R. Rose, 'Hominid Evolution and Social Science' Journal of Social and Biological Structures 6 (1983): 29-36; Jonathan Kingdon, Seif-made Man and his Undoing (London: Sirnon & Schuster, 1993), esp. pp. 98-123; Diamond, Third Chimpanzee; the contributions in Johan M.G. van der Dennen and V. Falger (eds.) Sociobiology and Conflict: Evolutionary Perspectives on Competition, Cooperation, Violence, and Warfare (London: Chapman & Hall, 1990; Christian Vogel, Vom Töten zum Mord: Das wirkliche Böse in der Evolutionsgeschichte (Munich: Ii"änser Verlag, 1989); Boone, 'Social Hierarchies', pp. 329-331. 108 For an early and limited review of the question "Why have scientists ignored the warfare hypothesis?" see Pitt, 'Brain Evolution', pp. 573-574. As an example of this neglect, in a collection devoted to "Machiavellian Intelligence" the editors recognise that

110

IV. Evolution and the Human Psyche

well-grounded and important proposal as the balance of power theory could be expected to receive a corresponding eamestness of consideration in those fields potentially affected. 109 Yet where it is considered it is often not treated as a hypothesis worthy of serious attention, 110 or is rejected on the basis of criteria "the social world contrasts with the physical world in that it is more challenging: thus intellectual capaeitles adapted to social life may have special and even pa.rticularly sophisticated attributes" (Andrew Whiten and Richard W. Byrne, 'The Machiavellian Intelligence Hypothesis: Editorial' in Richard W. Byrne and Andrew Whiten (eds.), Machiavellian lntelligence: Social Expertise and the Evolution of /ntellect in Monkeys, Apes, and Humans, pp. 13-26 (Oxford: Clarendon Press, 1988), p. 2). However, while including important a.rticles about the characteristics of social intelligence and its general usefulness, they fail to link these functional perspectives with the balance of power hypothesis that could provide an elegantly meshing phylogenetic account. Instead, in their section on the "social or non-social origins of intelligence" they include three a.rticles, the frrst of which is an essay on vervet monkeys, the second is Wynn's criticism of the tool-using theories quoted above, leaving the only attempt to explain the phylogenetic development as Milton's ironically non-social hypothesis: "Thus, the foraging and hunting behaviour of early humans was probably marked by increased complexity in communications skills, social skills, and technological skills over the australopithecine Ievel, and all of these behaviours are assumed to relate to greater mental complexity in our lineage. The precise factor or factors leading to selection for greater cerebral complexity and the successful performance of these behaviours remains obscure, but a climatic change and factors related to foraging efficiency and dietary energetics in the face of such change continue to be compelling candidates" (Katherine Milton, 'Foraging Behaviour and the Evolution of Primate Intelligence' pp. 284-305, p. 302). 109 Johanson and Shreeve comment that "generally speaking, paleoanthropologists today tend to shy away from speculations on early human social behaviour. We relish hard evidence, and start to squirm in its absence" (Johanson and Shreeve, Lucy's Child, p. 270). This is not an adequate explanation for the neglect of the balance of power theory however, as the anthropologicalliterature is littered with speculative explanations of hominid evolution, in comparison with which the balance of power model is weil specified and highly testable and falsifiable. For example, "in 1972 a Welsh writer, Elaine Morgan, proposed the Aquatic Ape scenario in which she suggested that the initial human adaptation was to life in the sea. The heat of the Pliocene, she claimed, drove ancestral females to the water to avoid predators and to cool off. The men followed." (Warren G. Kinzey, 'A Primate Model for Human Mating Systems' in Warren G. Kinzey (ed.), Primate Models for the Origin of Human Behavior, pp. 183-287 (Albany, NY: State University of New York Press, 1987), p. ix. Seegenerally ibid., pp. vüi-xi; Tooby and Devore, 'Strategie Modelling', pp. 212-226, and the other contributions to this volume. 110 Gowlett, for example, in an essay devoted to human mental evolution, does not explicitly consider any of the scholarly expositians of the balance of power hypothesis,

4. Accounting for Hominid Cognitive Development

111

which appear to derive from an emotional preference for 'nice' rather than 'nasty' human characteristics.lll In an ironic development such considerations may have influenced the editors of Machiavellian lntelligence to Iimit their selections to essays which examined cognitive skills in relations between individuals, 112 whereas Machiavelli hirnself focused on the central themes of the balance of power hypothesis: the relations between states, including the formation of alliances and the making of war; and relations within states, especially those that Ied to increased success in the extemal domain. 113 but devotes one paragraph to a popular exposition involving hunting and inter-group aggression: "although the hunting hypothesis has a propensity to stress human aggressive tendencies, this idea is tak.en to extremes in the 'killer ape' interpretation . . . This is justonein a series of extreme presentations, which stress one characteristic, or analogy, at the expense of all others . . . Territorial animals, Nak.ed Apes and suchlike, they succeed one another in an apparently endless progression." John A.J. Gowlett, 'Mental Abilities of Early Man: A Look at Some Hard Evidence' in Robert Foley (ed.), Hominid Evolution and Community Ecology: Prehistoric Human Adaptation in Biological Perspective, pp. 167-192, Studies in Archaeology Series (London: Academic Press, 1984), p. 171. Gowlett mak.es a parting comment about "a subject which has been overladen with oversimplified single-shot popular theories" (ibid., p. 171) and devotes the rest of the essay to a primarily descriptive consideration of "mental abilities" such as toolmak.ing. 111 For example a well-known cultural anthropologist commented, in a review of Johanson and Shreeve's Lucy's Child, that "intense sociallife also played apart, but why emphasize machiavellian skills alone? It tak.es at least as much intelligence to cooperate in the production and exchange of goods and services as to compete for them, And the need for Iove and approval is as much part of our primate heritage as our skills in lying and cheating. Could it be that Johanson is projecting his recent social experiences upon an innocent child?" Marvin Harris, 'Skeletons in the Family Cupboard' Guardian Weekly ( 10 December 1989): 20. 112 lt is instructive to note that the editors of the volume introducing this link to Machiavelli expected "to be criticised for appearing to emphasize the nastier side of primate social behaviour by the use of Machiavelli's name, which conjures up the use of superior knowledge and skill to deliberately manipulate, exp1oit, and deceive social companions" (Richard W. Byme and Andrew Whiten, 'Preface' in Richard W. Byme and Andrew Whiten (eds.), Machiavellian Intelligence: Social Expertise and the Evolution of Intellect in Monkeys, Apes, and Humans (Oxford: C1arendon Press, 1988), pp. v-vi at p. vi). 113 In Machiavelli's principal works, The Prince and The Discourses, he is concemed with the most effective types of personal rule and republican govemment, and only incidentally with the morality or otherwise of the statesmen invo1ved (Niccolo Machiavelli, The Discourses, ed. by Bemard Crick, trans. by Leslie J. Walkerand Brian Richardson (Harmondsworth, Middlesex: Penguin, 1983); Niccolo Machiavelli, The

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IV. Evolution and the Human Psyche

Whether for inter-individual, domestic, or inter-state reasons, all action is finally undertaken by individuals, however, and the explanation ofindividual behaviour and the psychological characteristics which underlie it form the themes of the next chapter.

Prince, trans. by George Bull (Harmondsworth, Middlesex: Penguin, 1984)). This is stressed by the prime definition of the adjective derived from his narne as "of or relating to the alleged political principles of Machiavelli; cunning, arnoral, and Opportunist" (Collins Dictionary, s.v. "Machiavellian" [my emphasis]); i.e., it relates primarily to political relations within and between states, and bears only secondarily upon relations between individuals.

V. From Psychology to Behaviour 1. Genet Maximisation a) Specification of Somatic Maximisation

Chapter III developed the general perspective of a hierarchy of maximising Ievels within adaptations, with each vehicle maximising the survival of 'its' genetic replicators, and with traits such as eating, child-care, or group defence leading to vehicle maximisation. All the mechanisms supporting such functionality were assumed to be the product of the individual organism, as it is only through the biochemical influence exerted by genetic replicators during the ontogenetic process that the mechanisms making up the transformation locus can be created. The expenditure of resources by organisms in the support of these vehicles can be termed effort. In addition to the traditionally recognised somatic and reproductive effort which Iead to the maximisation of replicator survival by the genet and kin-group vehicles respectively/ I assume the existence of community effort which is exerted by individuals for the group vehicle. The cognitive programs supporting genet maximisation are thus expected to have maximised the survival of the genetic replicators in the environment of evolutionary adaptedness, through somatic effort which: may be regarded as building the soma (phenotype, body, self) that willlater be used in reproduction. In a sense somatic effort is personally or phenotypically selfish. 2

It is this assumption of maximisation that allows us to specify that the net contribution of the somatic effort SE to the survival of genetic replicators (~ WsE) was maximised in the environment of evolutionary adaptedness, subject 1 See Alexander, 'Genes, Consciousness, and Behavior Theory', pp. 790-791; Alexander, Human Affairs, p. 104. These categories of effort will be abbreviated to SE andRE respectively. 2 Alexander, Moral Systems, p. 41. In my extended framework the soma may also be used for community effort for the group, or indeed as effort for other vehicles such as those within the genome.

8 Elworthy

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V. From Psychology to Behaviour

to the constraints on optimality, such as historical constraints and Iack of variation. We may thus assume that a form of cost-benefit maximisation took place in the evolutionary past, with the costs of somatic effort by the individual organism being incurred at a Ievel that maximised the benefit B; to the genet i less the cost C1 to the organism /, i.e.: [5.1]

Equation 5.1 is an ex post formulation, derived from the known properlies of the evolutionary process: the 'typical' organisms of the EEA satisfied this condition, and their genetic replicators survive in current populations. This expression does not cater for the behaviour of particular individuals in the EEA, however, as the statistical averaging process of natural selection operated to create the adaptation for an average constellation of genetic replicators from the gene pool. It is thus necessary to create an a priori formulation, which respecifies equation 5.1 in terms of the expected costs and benefits to members of groups composed of similar individuals with respect to the problern at band, denoted l. Let E represent an expectations term which may be applied to the expected costs of somatic effort to the representative organism i, and the expected retums from the somatic effort for the genet i. The expected result of the trait was the maximisation of replicator survival in the environment of evolutionary adaptedness, hence: [5.2]

Equation 5.2 can be assumed to have held for a particular genet in the environment of evolutionary adaptedness, but the principal concem of this work is to analyse behaviour in current environments. The !arge number of factors that may prevent the current maximisation of the survival of genetic replicators as the result of somatic effort, means that the maximisation of .:1WE(SEJ can no Ionger be assumed. A fundamental conclusion of the approach developed here is, however, that the failure to maximise äWEiSEJ in current environments does not invalidate the fundamental concept of maximisation. Current behaviour may be generally nonadaptive, so that the highest possible fitness indifference curves are not achieved, but this does not prevent behaviour being the product of maximising programs. Even when reed warblers are manipulated by cuckoos, for example, the inputs to these programs are affected by cues such as the yawning mouth of the offspring, so that the function of the behaviour is altered, rather than the

1. Genet Maximisation

115

genetic replicators of the cuckoos somehow affecting the ontogenetic sequence which produced the mechanisms. Some behaviour, such as that of ants infected with the fluke Dicrolium dendriticum may appear to invalidate this assumption of maximisation, as the psychological processes themselves may be altered by the parasite: By burrowing into the suboesophageal ganglion, the aptly named 'brainworm' changes the ant's behaviour. Whereas an uninfected ant would normally retreat into its nest when it becomes cold, infected ants climb to the top of grass stems, clamp their jaws in the plant and remain immobile as if asleep. Here they are vulnerable to being eaten by the worm's definitive host. The infected ant, like a normal ant, does retreat down the grass stem to avoid death from the midday heat - which would be bad for the parasite - but it returns to its aerial resting position in the cool of the aftemoon. 3

While the psychological mechanisms are certainly affected in this and similar cases, I would argue that this is best interpreted as the manipulation of inputs to cognitive and neurophysiological mechanisms that are lower in the functionlmechanism hierarchy. It is their functionality that is thus affected, but the genetic replicators of the "brainworm" do not affect the mechanisms which lie below this Ievel. Maximisation can thus still be assumed, but in a completely different space from that of an uninfected ant. Support for this interpretation can be found by observing that the ant does not display entirely arbitrary and 'senseless' behaviour, as witnessed by its descent during the midday heat. Rather, its somatic effort has been 'hijacked' by the fluke, while underlying mechanisms such as the movement of the legs and the clamping of the jaws still operate normally. This functionlmechanism distinction is a key difference between the approach developed here and that of Dawkins, who sees the ant's behaviour as an "extended phenotype" of the genetic replicators in the fluke: Even within a body there are many degrees of distance of gene control over phenotypes. For a nuclear gene to control the shape of the cell in which it sits is presumably simpler than to control the shape of some other cell, or of the whole body in which the cell sits. Yet we conventionally lump the three together and call them genetic control of the phenotype. My thesis has been that the slight further conceptual step outside the immediate body is a comparatively minor one.4

s•

3

Dawkins, Extended Phenotype, p. 218.

4

lbid. pp. 247.

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V. From Psychology to Behaviour

It is of the essence of my approach, that, rather than a "slight" further

conceptual step, a categorical difference exists between the creation of the mechanisms produced by replicators in the organism and the expression of these mechanisms as discussed above (page 68). It is then possible to assume that the behaviour still results in maxirnisation in the present, but that the maxirnisation is in general in another space from that of the survival of genetic replicators. In an extension of the concept of inclusive fitness maxirnisation to this new space 7t, the expected net benefit resulting from the somatic effort is denoted by 1t1E!SEJ" The characteristics of this space may be inferred from observation and related techniques, but it is not defined a priori, as was the case with historical inclusive fitness maxirnisation. In particular, behaviour may have been selected as somatic effort by the representative organism l for the genet i, but due to trade or expropriation the space may now have to include the effects upon vehicles x, y, z, . . . In the case of parasites, for example, the somatic resources of organism l may be used to support x's growth, y's reproduction, and so on. Appropriate respecification of equation 5.2 for behaviour in the present thus maxirnises in the new space 1tEISEJ• but leaves the other elements of the analysis unchanged: [5.3]

Equation 5.3 is essentially a static formulation, with the expectation terms reflecting the expected stream of costs and benefits associated with a specific action, whereas humans and all other organisms are continuously involved in the complex dynarnic process of life: Darwin's and Fisher's arguments Iead us to the hypothesis that, in evolutionary terms, every individual's lifetime is a series of unwitting cost-benefit decisions, leading, in the organism adapted to its environment, to a maximization of reproduction. 5

It is the entire lifetime that has been shaped by natural selection to maxirnise

replicator survival, and so it is thus convenient to conceive of somatic effort as being analogous to an econornic investment, incurring costs and bringing benefits over time. As in the econornic world, natural selection can be expected to have specified discount factors in the mechanisms instantiating equation 5.3, which achieved a statistical approximation to the discount rate required for the

5 Richard D. Alexander, 'Natural Selection and the Analysis of Human Sociality' in C.E. Goulden (ed.), Changing Scenes in the Natural Sciences, pp. 283-337, Bicentennial Symposium Monograph (Philadelphia Academy of Natural Science, Special Publication 12, 1977), p. 292 [hereafter Alexander, 'Natural Selection and Sociality'].

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maximisation of the survival of genetic replicators in the environment of evolutionary adaptation. The economic analysis of such investments is rather complex,6 and is more difficult in the current problern than the analysis for a single firm, because the costs and benefits accrue to different entities, the representative organism i, and the genet i, and these can be expected to have different discount rates and to involve evaluation over different periods. Let d11 measure the discount rate between benefits accruing between periods 0 and 1 to representative individual i, and du the corresponding value for the genet i, and Iet di2 and di2 represent the equivalent discount rates between periods 1 and 2. The net retum of the streams of benefits and costs in the new space 1t can then be assumed to be the the net present value of this somatic effort, hereafter net somatic value NSV. 7 The periods over which this value are assessed are from the present (0) until the expected death [E(D)] of the organism, and the expectations terms are respecified as e because they now primarily reflect uncertainty rather than the expected consequences of the action. An individual's somatic effort can be assumed to maximise NSV according to:

6 See e.g., Jack Hirshleifer, 'On the Theory of Optimal Investment Decision' Journal of Political Economy 66 (August 1958): 329-352. {Reprinted in Jack Hirshleifer, Time, Uncertainty, and Information Uncertainty and Expectations in Economics Series, pp. 537 (Oxford: Basil Blackwell, 1989)}. The specification of equation 5.4 is drawn from ibid., esp. pp. {22-23}.

7

This is to be interpreted as an equivalent of the economist's net present value

(NPV), but does not necessarily mean the maximisation of an equivalent of reproductive value, as the new space in all likelihood fails to correspond to inclusive fitness maximisation. It should be noted that the discount rates are intended to be much more concrete than those conventionally used in economics, which can be perceived by

imagining them applying to the somatic effort of a deciduous tree in, for example, growing leaves. In this case discount rates can be expected to exhibit strong cyclical pattems within each year, so that in the spring substantial somatic effort is devoted to leaves and associated structures, which presumably stabilises during the summer and declines in the autumn to zero.

V. From Psychology to Behaviour

118

max

[5.4]

+

(1 + di ,)(! + di 2) ... (1 + di E(Dl)

gcc; 1)

1

+

d;

gcc; 2)

I

(1

+

d; 1)(1

gcc; E(D))

+

d; 2)

Equation 5.4 is specified for the costs of a particular item of somatic effort incurred by the organism (as mechanism) and the benefits to the genet (as vehicle). The resources acquired by the genet are only intelligible in a phylogenetic sense in terms of their contributions to the k.in-group or group vehicles, however, and a complex dynamic pattem thus results between different forms of effort over an organism's lifetime. Figure 5.1 shows the basic pattems of a possible human lifetime, with the majority of effort being devoted to somatic effort during childhood and adolescence, which then reduces in adulthood. Reproductive effort climbs at maturity, but tails off as parental care gives way to extra-parental nepotism, such as for grandchildren. Community effort is shown with two phases: a peak at late adolescence corresponding to warfare or other forms of within-group cooperation and between-group competition, and a steady increase in later life corresponding to a position of leadership in the community. The specification of somatic maximisation, and its depiction over a hypotheticallifetime in figure 5.1, are very abstract and general. The following subsections discuss particular forms of behaviour, which illustrate how these theoretical principles may be instantiated in specific phenomena. b) Habitat Selection

An important aspect of genet maximisation is that it is directed towards the acquisition of resources which will be of use for particular purposes; in general those associated with the welfare of the individual concemed, tagether with the family and group to which he or she belongs. This implies that the physical environments that are found to be enjoyable will be those linked to successful hunting and gathering, reproduction, defence against predation and other

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1. Genet Maximisation

activities of the environment of evolutionary adaptedness. The investigation of cognitive programs which induce habitation in such favourable areas is weil suited to investigation from a phylogenetic perspective.

ro~--~~-------------------------------------,

80

70 60

community

RELATIVE EFFORT (percent)

~Iai

leaO!rship

effort

REPROOUCTIVE Effim !REl

20

%

ABSOWTE EFFORT

Figure 5.1 Levels of Effort over a Hypothetical Human Lifetime8

8 A similar depiction, but restricted to somatic and reproductive effort, is shown in Alexander, Moral Systems, fig. 1.2 p. 41.

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V. From Psychology to Behaviour

The EEA for such traits were almost certainly the grassland savannahs, especially those bordering on water, of Pleistocene East Africa, and has been considerable research into the nature of this environment.9 This hypothesis was investigated by Orians, who postulated that the existence of human preferences for such environments could be indirectly established by observing modern habitat selection mechanisms. 10 He focused on the reactions of the first explorers and settlers in the American West; the prices that are paid for various types of land; and the form that Iandscapes take when they are not subject to economic use, such as parks and gardens. His conclusions support the hypothesis that emotional and other mechanisms Iead to 'tastes' which would have resulted in the choice of the best available living spaces in the EEA: All three lines of evidence strongly suggest that we enjoy being in savannah vegetation, prefer to avoid both closed forests and open plains, will pay more for land giving us the impression of being a savannah, mold recreational environments to be more like savannahs, and develop varieties of omamental plants that converge on the shapes typical of tropical savannahs of Africa, the probable site of our evolutionary origins. 11

Roberts has investigated the details of this Pleistocene environment, and examined its changes over time (Neil Roberts, 'Pleistocene Environments in Space and Time' in Robert A. Foley (ed.) Hominid Evolution and Community Ecology: Prehistoric Human Adaptation in Biological Perspective, pp. 24-53, Studies in Archaeology Series (London: Academic Press, 1984), esp. pp. 44-46). For general analyses of the relationship between the physical environment and hominid development see Foley, Another Unique Species, passim; Robert Foley, 'The Ecological Conditions of Speciation: A Comparative Approach to the Origins of Anatomically-Modem Humans' in Paul Mellars and Chris Stringer (eds.), The Human Revolution: Behavioural and Biological Perspectives on the Origins of Modem Humans, pp. 455-513 (Princeton, NJ: Princeton University Press, 1989); Robert A. Foley, 'The Evolution of Hominid Soda! Behaviour' in Valerie Standen and Robert A. Foley (eds.), Comparative Socioecology: The Behavioural Ecology of Humans and Other Mammals, pp. 473-494, Special Publication Number 8 of the British Ecological Society (Oxford: Blackwell Scientific Publications; 1989). 9

10 Gordon H. Orians, 'Habitat Selection: General Theory and Applications to Human Behavior' in Joan S. Lockard (ed.), The Evolution of Human Social Behavior, pp. 49-66 (New York: Elsevier North Holland, 1980) [hereafter Orians, 'Habitat Selection']. For a recent extension of this analysis see Gordon H. Orians and Judith H. Heerwagen, 'Evolved Responses to Landscapes' in Jerome H. Barkow, Leda Cosmides, and John Tooby (eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, pp. 555-579 (Oxford: Oxford University Press, 1992). 11

Orians, 'Habitat Selection', p. 64.

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c) Responses to Hazards and Risks

Maximising net somatic value implies that individuals should avoid situations which have high expected costs. The net somatic benefits to the genet can be expected to have a relatively low variance: as with profit maximising firms in competitive environments, so individuals in the environment of evolutionary adaptedness can be expected to have rarely achieved "super-normal profits". Immediate and !arge reductions may, in contrast, occur through the occurrence of 'mistakes', just as a firm may easily become insolvent through error or malevolence. The most obvious high-cost situations are those where the genet' s life is threatened, and humans are thus expected to take immediate and extreme measures in order to escape from such mortal dangers. Nesse has postulated that such an historically adaptive response underlies the phenomenon of panic, where the goal of escape overrides all other behavioural motivations. 12 Nesse uses the functionality of real panic in investigating the psychiatric conditions known as "panic disorder" and "agoraphobia", thus providing an example of the insights into cognitive processes achievable through analysis of maladaptive behaviour. Panic disorder generally takes the following form: The problern typically begins with a sudden attack of overwhelming anxiety that occurs "from out of the blue" while the person is away from home. A feeling that death is imminent and an overwhelming need to "get out of here" displace all other thoughts. Shortness of breath and pounding of the heart precede actual movement. Sweating, flushing, dizziness, ehest pain, and other physical symptoms are common. The episode last [sie] 15-45 minutes and is followed by exhaustion for 24 hours. 13

Panic disorder is also called Dacoste's syndrome, soldier's heart, neurasthenia, and anxiety hysteria. It is relatively common, with a six-month prevalence in !arge United States cities of approximately six per thousand for men and ten per thousand for women. 14 The corresponding rates for agoraphobia are twenty per thousand and fifty per thousand, a condition which is almost always associated with a history of repeated panic attacks. Rather than experiencing relatively short periods of anxiety from "out of the blue", however, patients sufferlog from agoraphobia tend to:

12 Randolph M. Nesse, 'An Evolutionary Perspective on Panic Disorder and Agoraphobia' Ethology and Sociobiology 8(3S) (1987): 73S-83S [hereafter Nesse, 'Panic Disorder']. 13

Ibid., p. 75S.

14

lbid. , p. 75S.

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122

experience intense anxiety in certain Situations - being alone or in crowds, being in a wide open space, or being anyplace where exit is difficult, especially lines, movies, or airplanes. 1' lt is interesting to note the mesh with the habitat choice analysis, as the grassland savannah with its occasional trees provided an environment between the extremes of the enclosed space of the jungle or forest and the openness of deseits or treeless plains. The retum to the security of family relationships, the similarity of the physical and mental conditions with those associated with flight from danger, and numerous other aspects of these conditions serve to support Nesse's hypotheses that:

The abnormality in people with panic disorder is not the occurrence of panic per se, but rather that the attacks occur when there is no real danger; and that agoraphobia can best be understood as a potentially adaptive consequence of repeated panic attacks. 16

These hypotheses are much more consistent with the associated physiological and behavioural phenomena than those derived from alternative approaches based on Freudian analysis, leaming theory, neurochemical mechanisms, or genetic imperfections, 17 although elements of such approaches will in all probability be included in explanations of the underlying mechanisms. The cognitive programs involved in escaping from danger are probably related, for example, to other cognitive programs such as those preventing separation from the mother; are ultimately instantiated in neurochemical mechanisms; are likely to involve leaming from experience and the environment; and will vary with genetic differences in the population. The compatibility of these specific hypotheses with Nesse's explanation results from the generality of phylogenetic and functional explanations, which provide an interpretive framework in which the various proximate and ontogenetic factors can be understood. Panic involves the protection of life and limb through flight from a threatening situation, and individuals exhibiting panic disorder and agoraphobia can be interpreted as the most risk-averse of the population in these domains. Just as such extremely risk-averse reactions are unintelligible to the bulk of the population for whom open spaces as such provide 'no reason' to panic, so other

IS

Jbid.

16

lbid., p. 74S.

17

See e.g., ibid., pp. 76S-78S.

1. Genet Maximisation

123

forms of behaviour are interpreted as 'senseless' or 'irrational' because of their risk-seeking qualities. Consider the following account: One time I was in the men's room of the bar and there was a guy at the urinal. He was kind of drunk, and said to me in a mean-sounding voice, "I don't like your face. I think l'll push it in." I was scared green, I replied in an equally mean voice, "Get out of my way, or 1'11 pee right through ya!" He said something e1se, and I figured it was getting pretty close to a fight now. I had never been in a fight. I didn't know what to do exactly, and I was afraid of getting hurt. I did think of one thing: I moved away from the wall, because I figured if I got hit, l'd get hit from the back, too. Then I feit a sort of funny crunching in my eye- it didn't hurt much- and the next thing I know, l'm slamming the son of a gun right back, automatically. lt was remarkable forme to discover that I didn't have to think; the "machinery" knew what to do. "OK. That's one for one," I said. "Ya wanna keep on goin'?" The other guy backed off and left. We would have killed each other if the other guy was a dumb as I was. 18

Feynman's perception is correct: such "trivial altercations" which typically take place between men, and often involve apparently senseless disputes in bars and streets, "constitute the most prevalent variety of hornicide in the United States" . 19 Wilson and Daly have termed this form of behaviour "the young

18 Richard P. Feynman, 'Surely You're Joking, Mr Feynman!': Adventures of a Curious Character, as told to Ralph Leighton (London: Unwin Paperbacks, 1986), p. 177.

19 Daly and Wilson, Homicide, p. 125, see generally pp. 123-136, pp. 170-176, esp. tables 8.1 p. 174 and 8.3 p. 176. The subjective account by Feynman is fascinating because of his clarity of analysis, as reflected, for example, in his moving away from the wall and the automatic retum of the punch, and because, as winner of the Nobel Prize for physics in 1965, he can scarcely be Iabelied 'irrational'. This personal perspective is corroborated by the accounts of observers, as in this summary from a Dallas homicide detective: "murders result from little ol' arguments over nothing at all. Tempers flare. A fight starts, and somebody gets stabbed or shot. l've worked on cases where the principals had been arguing over a 10 cent record on a juke box, or over a one dollar gambling debt from a dice game." (cited in ibid., p. 127). Another advantage of the Feynman passage is that it helps to overcome the classification of such disputes as being "trivial" or about "nothing at all", so that an "implicit contrast is drawn between the foolishness of violent men and the more rational motives that move sensible people like ourselves. The combatants are in effect denigrated as creatures of some lower order of

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male syndrome",20 because it is typically exhibited by young males engaged in status competition with each other. The functionality of this behaviour in the environment of evolutionary adaptedness arises from the fundamentally different characteristics of the reproduction of human males and females. As with many other species, including the majority of animals, females have evolved to invest their somatic resources in their offspring, which are limited in number by physiological constraints, such as the gestation period. Human males, however, arenot limited in their reproductive success by such physical characteristics, but rather by the number of females to whom they gain sexual access. lt is possible for one male to utilise the reproductive resources of numerous females, and many males have done this in recorded history, 21 whereas females normally have little if any gain from multiple mates. 22 The consequence is that in humans, as in many other species, the variance of male reproductive success was higher than that of females in the evolutionary past: a male hunter/gatherer with one wife (who will probably produce four or five children during her lifetime) may increase his reproductive success an enormous 20 to 25 percent if he sires a single child by another woman during his lifetime. If he can obtain (and support) a second wife, he may double his reproductive success. The reproductive realities facing his wife are very different. She will bear four or five children during her lifetime whether she copulates with one, ten, or a thousand men. 23

mental functioning, evidently govemed by immediate stimuli rather than by foresightful contemplation" (ibid.) 20 Margo Wilson and Martin Daly, 'Competitiveness, Risk Taking, and Violence: The Young Male Syndrome' Ethology and Sociobiology 6 (1985): 59-73 [hereafter Wilson and Daly, 'Young Male Syndrome']. 21

See e.g., Betzig, Despotism and Differential Reproduction, esp. pp. 79-86.

An exception are polyandrous marriages which involve simultaneaus cohabitation, such as those of Ladakh and Tibet, which appear to have been adaptive in the EEA because they resulted in the retention within the family of critical heritable resources. See Alexander, 'Evolution of Social Behavior', p. 348, pp. 371-372; John Hurrel Crook and Stamati J. Crook, 'Tibetan Polyandry: Problems of Adaptation and Fitness' in Laura Betzig, Monique Borgerhoff Mulder, and Paul Turke (eds.), Human Reproductive Behaviour: A Darwinian Perspective, pp. 97-114 (Cambridge: Cambridge University Press, 1988); Alexander, 'Future', pp. 335-336; Daly and Wilson, Sex, Evolution, and Behavior, pp. 286-288. 22

23

Symons, Human Sexuality, p. 207.

1. Genet Maximisation

125

This history of generally polygynous sexual relationships is supported by anthropological research on marriage pattems among human societies. 24 The high variance in male reproductive success that typically characterises polygynous societies implies intense competition among men in the evolutionary past for resources which provided reproductive opportunities, the essence of sexual selection: What governs the operation of sexual selection is the relative parental investment of the sexes in their offspring. Competition for mates usually characterizes males because males usually invest almost nothing in their offspring. 25

If human societies were effectively polygynous in the environment of

evolutionary adaptation, so that males displayed high variance in the numbers of genetic replicators they contributed to succeeding generations, then sexual selection is expected to have provided mechanisms that led to success in intermale competition. The existence of sexual size dimorphism between human males and females which correlates with the degree of societal polygyny, and which parallels similar systematic dimorphism among other orders, lends strong support to this hypothesis. 26 Equivalents in mental argans to this

24 Murdock in a sample of 849 human societies found occasional or usual polygyny in 708, monogamy in 137, and polyandry in 4 (George Peter Murdock, Ethnographie Atlas (Pittsburgh: University of Pittsburgh Press, 1967), reported in Daly and Wilson, Sex, Evolution, and Behavior, p. 282. The toleration of polygyny does not necessarily imply that such marriages are common: "polygynous unions remain rarer than monogamaus ones, however, even within those societies that permit them" Daly and Wilson, Sex, Evolution, and Behavior, p. 282). Monogamy tends to characterise the smallest societies such as Eskimos, Laplanders, and Andaman Islanders, where it appears to be ecologically imposed, and the largest societies such as China, and the United States, where it is legally required; see Alexander et. al., 'Sexual Dimorphisms', p. 418420; Alexander, Human Affairs, pp. 256-264, esp. fig. 13 p. 260; Alexander, Moral Systems, pp. 70-73; Mark V. Flinn and Bobbi S. Low, 'Resource Distribution, Social Competition, and Mating Patterns in Human Societies' in Danie1 I. Ruhenstein and Richard W. Wrangharn (eds.), Ecological Aspects of Social Evolution, pp. 217-243 (Princeton, NJ: Princeton University Press, 1986), pp. 221-228 [hereafter Flinn and Low, 'Mating Patterns'].

25 Robert L. Trivers, 'Parental Investment and Sexual Selection' in Bernard Grant C:ampbell (ed.), Sexual Selection and the Descent of Man, 1871-1971, pp. 136-179 (Chicago: Aldine, 1972), p. 141 [hereafter Trivers, 'Parental Investment'].

26 See Alexander et al., 'Sexual Dimorphisms' , esp. pp. 415-417. Such morphological differences between human societies that correlate with phylogenetic functionality are not unique: recent populations also display traits in accordance with

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V. From Psychology to Behaviour

morphological dimorphism are also expected, and one set of such cognitive programs is "the young male syndrome", which was presumably involved in Feynman's fight. 27 Support for the hypothesis that such psychological processes are the result of inter-male competition is provided by the social and demographic characteristics of those who most often express this form of behaviour- the young low-status males whose predecessors are expected to have fathered relatively few children in the environment of evolutionary adaptation. 28 Further evidence is offered by the very high rate of automobile accidents experienced by young men, who are typically engaged in risky activities such as speeding or refusing to yield

Bergmann's and Allen's "rules", so that "humans who are indigenous to cold areas do tend to have, respectively, greater body masses and shorter extremities than those who live in warmer climates. By these means, the surface area through which body heat can be lost is minimized compared to body volume" (Stringer, 'Adaptation in the Pleistocene', p. 68; see generally pp. 67-71, esp. fig. 3.2 p. 70). As with psychological characteristics, such consistent morphological differences between human groups could either result from functional genetic differences, as is presumably the case with differences in skin colour and body proportions between races, or from "conditional strategies", where all populations possess the requisite genetic replicators for all forms, and the actual developmental path depends upon relevant aspects of the environrnent, as with sexual differentiation. 27 "We expect a taste for competitive risk taking to be an evolved aspect of masculine psychology as a result of sexual selection. If male fitness derives from success in risky competition, then males are expected to join such competition willingly, given reasonable prospects of success." Wilson and Daly, 'Young Male Syndrome', p. 66. A numerical simulation which shows the high inclusive fitness payoffs to risky strategies in a highly competitive environrnent is provided in Daly and Wilson, Homicide, Box 8.1, pp. 164-167. As repeatedly stressed above, thesehigh payoffs were in the space of the actual survival of genetic replicators in the EEA, (!J.W5E). Current behaviour is still assumed to be maximising in some space, and may in fact maximise status in the relevant environrnent of the 'peer-group', but need not maximise the survival of genetic replicators. The directions that research can take when functional explanations are neglected and proximate mechanisms focused upon is illustrated by the search for the influence of gonadal hormones and other physiological traits upon sensation seeking, in Marvin Zuckerman, Monte S. Buchsbaum, and Dennis L. Murphy, 'Sensation Seeking and Its Biological Correlates' Psychological Bulletin 88(1) (July 1980): 187-214.

28 See e.g., Wilson and Daly, 'Young Male Syndrome' , pp. 62-66; Alexander, Human Affairs, pp. 240-248; Daly and Wilson, Homicide, pp. 168-173.

1. Genet Maximisation

127

right of way,29 and the "affairs of honour" that characterise many societies, and were manifested in European societies as duels. 30 d) Avoidance of Unprofitable Investment

The sexual selection which resulted in the "young male syndrome" arose from the differential parental investment of males and females, and while parental investment itself is an aspect of the kin-group vehicle, the prevention of unprofitable investments can be interpreted in terms of somatic maximisation. Like mechanisms such as panic, this prevents the loss of somatic resources through Situations or activities which would not have maximised inclusive fitness in the environment of evolutionary adaptedness. Given the high costs involved with child-bearing, it is to be expected that females developed mechanisms which prevented reproduction in inappropriate periods and situations. The "reproductive suppression model" draws on hypotheses of this type developed by Fisher and Williams, 31 positing that: When future conditions may be expected to be better ones, individua1s may be able to maximise their reproductive success (RS) by suppressing their reproduction until that future time. 32

29

See Wilson and Daly, 'Young Male Syndrome', p. 68.

Interestingly, Axelrod chose Alexander Hamilton's duel in 1804 which resulted in Hamilton' s death as the initial example of the strength of social norms (Robert Axelrod, 'An Evolutionary Approach to Norms' American Political Science Review 80(4) (1986): 1095-1111, p. 1095 [hereafter Axelrod, 'Evolutionary Approach to Norms']). See also Robert Axelrod, 'Laws of Life: How Standards of Behavior Evolve' The Seiences 17 (March/April 1987): 44-51; Robert Axelrod, 'Beyond Moral CalculusReply' The Seiences 27(5) (September-October 1987): 15-16). 30

31 Fisher, Genetical Theory, esp. chap. 2; George C. Williams, 'Natural Selection, the Costs of Reproduction, and a Refinement of Lack's Principle' American Naturalist 100(916) (November-December 1966): 687-690, esp. p. 688. 32 Samuel K. Wasser and David P. Barash, 'Reproductive Suppression among Fernale Mammals: Implications for Biomedicine and Sexual Selection Theory' Quarterly Review of Biology 58(4) (December 1983): 513-537, p. 516. For applications to humans see e.g., William P. Bernds and David P. Barash, 'Early Termination of Parental Investment in Mammals, lncluding Humans' in Napoleon A. Chagnon and William G. Irons (eds.), Evolutionary Biology and Human Social Behavior: An Anthropological Perspective, pp. 487-506 (North Scituate, MA: Duxbury Press, 1979); Elizabeth M. Hili and Bobbi S.

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This hypothesis thus implies that individuals consciously or unconsciously predict future costs and benefits of behaviour, as specified in equation 5.4 (page 118), and these predictions can be expected to involve discount rates derived from species-typical lifetimes in the environment of evolutionary adaptedness, an example of which is shown in figure 5.1 (page 119). Surbey has applied this theoretical framework to anorexia nervosa, which is characterised by a relentless pursuit of thinness and an exaggerated fear of becoming fat. It is often triggered by dieting that eventually causes severe emaciation. The typical anorexic is female, adolescent, and from a home that is above average in income.33

Surbey reasoned that the amenorrhea and loss of libido associated with the condition could be similar to traits in female mammals which delay or interrupt reproduction. 34 The self-starvation thus serves to temporarily suspend reproductive characteristics so that the anorexic returns to an essentially prepubertal state, a hypothesis that is compatible with the observation that a large proportion of affected women recover and have children. 35 Further evidence for this reproductive suppression explanation is an interpretation of the detailed case histories of nineteen anorexics conducted by Voland and Voland, who conclude that the low average age, and the high frequency of association of the illness with firstsexual experiences, provide direct support for the hypothesis.36 Anorexia nervosa prevents conception by suppressing the mechanisms that normally result in reproduction. Infanticide can be viewed as a process which

Low, 'Contemporary Abortion Patterns: A Life History Approach' Ethology and Sociobiology 13(1) (January 1992): 35-48. 33 Micheie K. Surbey, 'Anorexia Nervosa, Amenorrhea, and Adaptation' Ethology and Sociobiology 8(3S) (1987): 47S-61S, p. 48S [hereafter Surbey, 'Anorexia Nervosa']. It is a condition which may affect at least one percent of American women (ibid.) .

34

/bid. p. 48S. Amenorrhea refers to the abnormal absence of menstruation.

35

Ibid., pp. 50-51S, 56-57S.

Eckart Voland and Renate Voland, 'Evolutionary Biology and Psychiatry: The Case of Anorexia Nervosa' Ethology and Sociobiology 10(4) (1989): 223-240 [hereafter Voland and Voland, 'Anorexia Nervosa']. The average age is between 17 and 18 and almost all female patients contract anorexia nervosa before they are 25. First intimate relations and the onset of anorexia nervosa were linked in 34%, 36%, and 47% of the cases in the three studies reported (ibid., p. 226). For further discussions of anorexia nervosa from an evolutionary perspective, and a comparison with competing theories, see Charles Crawford, 'The Theory of Evolution: Of What Value to Psychology?' Journal of Comparative Psychology 103(1) (1989): 4-22, pp. 17-19. 36

1. Genet Maximisation

129

stops parental investment at a later stage, being defined as "any form of Iethai curtailment of parental investment in offspring brought about by conspecifics".37 Explanations of human infanticide from an evolutionary perspective have analysed the willingness of parents to undertake parental investment on the following grounds: 1. What is the genetic relationship of the putative offspring to its parents? (ls this juvenile really my own offspring?) 2. What is the need of the offspring? (More properly, what is its ability to translate parental assistance into reproduction?) 3. What alternative uses might a parent make of the resources it can invest in the offspring?38

Daly and Wilson have made use of this general categorisation in investigating the motivations for infanticide as revealed in the ethnographic record, interpreting the three classes in terms of the justifications provided for killing or failing to support a particular child: The frrst such class consists of circumstances in which there is some doubt that the offspring in question is indeed the putative parent's own. The second class encompasses indications that the offspring itself may be of dubious quality, and hence a poor prospect to contribute to parental fitness, even if carefully nurtured. . . . The third class of reasons why we might encounter a dampened parental enthusiasm includes all those extrinsic circumstances that might bode ill for a particular childrearing effort: food scarcities, a Iack of social support, overburdening from the demands of older offspring, and so forth. 39

The importance of these reasons was tested by using the standard "Probability Sample" from the Human Relations Area Files. Daly and Wilson then

37 Sarah Blaffer Hrdy and Glenn Hausfater, 'Comparative and Evolutionary Perspectives on Infanticide: Introduction and Overview' in Glenn Hausfater and Sarah Blaffer Hrdy (eds.), lnfanticide: Comparative and Evolutionary Perspectives, pp. xiü-xxxv (Hawthorne, NY: Aldine de Gruyter, 1984), p. xv. 38

Alexander, Human Affairs, p. 109.

Daly and Wilson, Homicide, p. 44. This research was frrst presented in Martin Daly and Margo Wilson, 'A Sociobiological Analysis of Human lnfanticide' in Glenn Hausfater and Sarah Blaffer Hrdy (eds.), lnfanticide: Comparative and Evolutionary Perspectives, pp. 487-502 (Hawthorne, NY: Aldine de Gruyter, 1984). See also Martin Daly and Margo Wilson, 'Children as Homicide Victirns' in Richard J. Geilesand Jane B. Lancaster (eds.), Child Abuse and Neglect: Biosocial Dimensions, pp. 201-214 (Hawthorne, NY: Aldine de Gruyter, 1987). 39

9 Elworthy

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V. From Psychology to Behaviour

enumerated 112 stated circumstances of infantleide from those 35 societies for which the topic was discussed at all. A small nurober of themes predominated .. . themes corresponding precisely to the three issues that we have already suggested should be relevant to adaptive parental decision-making. 40

The overwhelming majority (ninety-seven of 112) are directly interpretable in terms of these three categories. Four societies gave the female sex of the baby as a reason for infanticide, which may be explainable in terms of femaleselective infanticide by high-ranking parents. 41 Because in the general population equivalent Ievels of parental investment are expected to be devoted to daughters as to sons, as in aggregate each sex has the same probability of contributing genetic replicators to the next generation,42 there is an expectation of male-selective infanticide among low-ranking parents, and Voland has presented evidence that such a switch may indeed take place.43 Of the

40

Daly and Wilson, Homicide, p. 47.

See Mildred Dickemann, 'Demographie Consequences of Infanticide in Man' Annual Review of Ecology and Systematics Richard F. Johnston, Peter W. Frank, and Charles D. Michener (eds.), 6 (1975): 107-137, p. 129-130; Mildred Dickemann, 'Female Infanticide, Reproductive Strategies, and Social Stratification: A Preliminary Model' in Napoleon A. Chagnon and William G. Irons (eds.), Evolutionary Biology and Human Social Behavior: An Anthropological Perspective, pp. 321-367 (North Scituate, MA: Duxbury Press, 1979), passim; Robert L. Triversand Dan E. Willard, 'Natural Selection of Parental Ability to Vary the Sex Ratio of Offspring' Science 179 (5 January 1973): 90-92; Alexander, Moral Systems, pp. 24-30. 41

The reason for this was frrst identified by Fisher who showed that under standard conditions, producing a one-to-one sex ratio was the best strategy that a parent could adopt (Fisher, Genetical Theory). This general rule is subject to numerous exceptions, as in Rarnilton' s model where local competition for mates is more intense for one sex than another (William D. Hamilton, 'Extraordinary Sex Ratios' Science 156 (28 April 1967): 477-488). See also Alexander, 'Evolution of Social Behavior'; Trivers and Willard, 'Sex Ratio'. 42

43 Eckhart Voland, 'Human Sex-Ratio Manipulation: Historical Data from a German Parish' Journal of Human Evolution 13 (1984): 99-107, esp. tables 1 p. 101 and 2 p. 103; Eckhart Voland, 'Differential Infant and Child Mortality in Evolutionary Perspective: Data from Late 17th to 19th Century Ostfriesland (Germany)' in Laura Betzig, Monique Borgerhoff Mulder, and Paul Turke (eds.), Human Reproductive Behaviour: A Darwinian Perspective, pp. 253-261 (Cambridge: Cambridge University Press, 1988), pp. 256-257; Eckhart Voland, 'Differential Parental Investment: Some Ideas on the Contact Area of European Social History and Evolutionary Biology' in Valerie Standen and Robert A. Foley (eds.), Comparative Socioecology: The Behavioural Ecology of Humansand Other Mammals, pp. 391-403, Special Publication Nurober 8 of

1. Genet Maximisation

131

remaining eleven from the 112 cases not accounted for by female-selective infanticide or the three primary categories, explanations appear to involve intervention or coercion by parties other than the parents, or special circumstances.44 In addition to these anthropological reports of motivation, indirect evidence for the existence of specialised cognitive processes goveming the withholding of parental investment can be obtained by examining the characteristics of the parties involved. A particularly sensitive hypothesis that Daly and Wilson have investigated is that "substitute parents will generally tend to care less for their children than natural parents, with the result that children reared by people other than their natural parents will be more often exploited and otherwise at risk".45 This was strongly upheld for infanticide data from a variety of societies. A study of Ache Indians, for example, found that: Children whose reported bio1ogical fathers die before they are 15 years old and are raised by other men, have significantly higher mortality than those whose reported biological fathers remain alive and married to their mothers (43.3% of n = 67 vs. 19.3% of n = 171 die before the age of 15, = 13.2, p < 0.001).46

r:

Studies in England, Australia, the United States and Canada of children living with two genetic parents, as compared to one genetic and one substitute parent,

the British Ecological Society (Oxford: Blackwell Scientific Publications, 1989), pp. 396401; Eckart Voland, Eva Siegelkow, and Claudia Engel, 'Cost/Benefit Orientated Parental Investment by High Status Families: The Krummhörn Case' Ethology and Sociobiology 12(2) (March 1991): 105-118. 44 lronically the only reported case where the protagonist's actions can not be interpreted in terms of inclusive fitness maximisation is reported by Chagnon, generally known for his Championship of the evolutionary approach to anthropology: "Young couples do not relish the prospect of a long period of celibacy that pregnancy and Iactation taboos impose on them. From the time a woman discovers she is pregnant until the time she weans her child, she is not allowed to have sexual relations. Faced with this prospect, young couples may decide to kill their child, irrespective of its sex." (Napoleon A. Chagnon, Yanomamö Waifare, Social Organisation and Marriage Alliances (Ph.D. thesis, University of Michigan, 1967), p. 55 cited in Daly and Wilson, Homicide, p. 58). This is clearly compatible with the maximisation of sexual pleasure, and is thus interpretable in terms of equation 5.4.

45

Daly and Wilson, Homicide, p. 83.

Kim Hill and Hillard Kaplan, 'Tradeoffs in Male and Fernale Reproductive Stratgies among the Ache: Part II' in Laura Betzig, Monique Borgerhoff Mulder, and Paul Turke (eds.), Human Reproductive Behaviour: A Darwinian Perspective, pp. 291 -305 (Cambridge: Cambridge University Press, 1988), p. 298. 46

132

V. From Psychology to Behaviour

show that the probability that a child will be fatally bauered is substantially higher in the latter than in the former case. Figure 5.2 shows the dramatic support of the prediction for the Canadian study. Daly and Wilson have additionally investigated other aspects of the psychological processes involved in infanticide, such as the effect of the rnother's age,47 the child's age,48 and the nature of the matemal bonding process,49 and have linked these results to nonfatal cases of child abuse. 50 This research strongly upholds the hypothesis that specialised cognitive programs which were shaped by natural selection in the environrnent of evolutionary adaptedness guide the direction of sornatic resources. lt further illustrates the intirnate link between genet maxirnisation and kin-group rnaxirnisation, the subject of the next section.

47 "We may expect matemal psychology to exhibit sensitivity to the mother's own residual reproductive value: A newbom's compromising effects on the mother' s future diminish with matemal age, and hence matemal willingness to jettison an infant may be expected to decrease. This prediction is upheld." Martin Daly and Margo Wilson, 'Evolutionary Social Psychology and Family Homicide' Science 242 (28 October 1988): 519-524, at p. 522 [hereafter Daly and Wilson, 'Evolutionary Social Psychology'].

48 "In ancestral environments, the child's probability of attaining adulthood and contributing to its own and its parents' genetic posterity increased with age, especially during infancy, as the child passed through a stage of high mortality risk. The predicted consequence is that parental psychology should have evolved to cherish the child increasingly over a prolonged period, as the child's reproductive value increased." Daly and Wilson, 'Evolutionary Social Psychology', p. 522. Three predictions derived from this hypothesis were supported by Daly and Wilson's Canadian data (ibid. fig. 4 p. 522). 49 Martin Daly and Margo Wilson, 'Evolutionary Psychology and Farnily Violence' in Charles Crawford, Martin Smith, and Dennis Krebs (eds), Sociobiology and Psychology: Ideas, /ssues and Applications, pp. 293-309 (Hillsdale, NJ: Lawrence Erlbaum Associates, 1987), pp. 296-301; Daly and Wilson, Homicide, pp. 69-72.

so Martin Daly and Margo Wilson, 'Abuse and Neglect of Children in Evolutionary Perspective' in Richard D. Alexander and Donald W. Tinkle (eds.), Natural Selection and Social Behavior: Recent Research and New Theory, pp. 405-416 (New York: Chiron Press, 1981 ); Margo Wilson and Martin Daly, 'Risk of Maltreatment of Children Living with Stepparents' in R.J. Gelles and J.B. Lancaster (eds.), Child Abuse and Neglect pp. 215-232 (New York: Aldine, 1987), esp. pp. 221-225.

2. Kin-Group Maximisation

133

100

1:

~

j~ 0 c

500

0

400

u c c •

~

~8. E .,

Z.l ~'D

.,'D

300

E:!!

=::c

~1

200

~l 0

100

~i

:z:

0

D-2

3-5

6-8

9-11 12-1415-17 Age of chlld (y•ra)

Figure 5.2 Age-Specific Rates of Homicide Victimization by (A) Genetic Parents or (B) Stepparents51

2. Kin-Group Maximisstion a) Specification of Kin-Group Maximisation

Whereas mechanisms for the genet vehicle centre upon growth, and the acquisition of somatic resources, those for the kin-group vehicle centre upon reproduction: the progression from adult humans, through the single cell stage so critical for the evolution of complex adaptations, and thence through the ontogenetic development sequence, to result in another adult human. The key factor which distinguishes the genet from the kin-group is that the former applies to only one organism, whereas the former involves at least two, such as a parent and child. It is this multiple membership of the kin-group vehicle that prevents functional maximisation being simply specified for individuals within it: the maximisation is exhibited by the kin-group itself. This normally requires

51 Reprinted, with permission from the AAAS and the authors, from Martin Daly and Margo Wilson, 'Evolutionary Social Psychology and Family Homicide' Science 242 (28 October 1988): 519-524, fig. 1 p. 520 (copyright 1987 by the AAAS). The data are for Canada, 1974-1983, n = 341 victims in (A) and n = 67 victims in (B), and the figure is adapted from Daly and Wilson, Homicide, Figure 4.9 p. 90.

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V. From Psychology to Behaviour

the transfer of resources among kin-group rnernbers, irnplying costs for sorne and benefits for others. This will generally involve functional maximisation at a succession of hierarchical levels, descending through to physiological and biochemical processes, but an intuitive understanding generally requires the identification of the 'purpose' of the highest levels, which then provides a framework in which the others can be understood. The fundamental assumption is then that the costs incurred by an organisrn for the kin-group (C1), termed reproductive effort (RE), maximised the survival of genetic replicators (L\WRE) ex post in the environment of evolutionary adaptedness. The organisms benefited were not the genet i, as in the previous section, but the member or rnembers of the kin-group who were the beneficiaries of the reproductive effort, i.e. j 1, j 2, j 3, ••• , jn. Nor were these benefits valued in the simple way of equations 5.1 to 5.4 (pages 114-118), but were rather weighted by the coefficient of relationship r11 between the organisrn and its relations. lt was the sum of these weighted benefits to the kin-group, less the cost to the organism, that was maximised in the environment of evolutionary adaptedness, i.e., [5.5]

max

!!. WRE

•

=

L

j • I

(r11 B1 ) - C1

In a similar manner tothat used to derive equation 5.2 (page 114), this may be converted into an a priori formulation by replacing the actual with the expected benefits and costs. The coefficient of relationship is 'expected' in a different sense from the other terms, however, in that it is knowable with certainty in principle and sornetimes in practice, such as the fifty percent of genetic replicators that were shared by a woman and the child she gave birth to. 52 As this is thus closer to the economist' s conception of risk than the unknowable future costs and benefits which involve uncertainty, it is separately specified as c(r1). The expected result of the traits of a representative individual's reproductive effort in the environment of evolutionary adaptedness can then be specified as: [5.6]

max

!!. WE(RE >

•

L

j • I

E (r11)E(B1)

- E(C1)

52 This was clearly true of the environment of evolutionary adaptedness, although new reproductive technology, such as embryo transplants, has affected this certainty today.

135

2. Kin-Group Maximisation

For the same reasons as advanced for somatic effort, equation 5.5 can be respecified for the present in terms of maxirnisation in a new space represented by 1tE!REJ• and a representative individual i, giving: [5.7]

max

1t E =

•

L

j • I

e (ri 1) E (81)

E(Ci)

-

Finally the dynarnic character of the maxirnisation can be made explicit by inclusion of the time dimension. The k.in-group is unlike the genet, however, in that it does not end with the death of the representative individual i, but continues to exist in the form of the remaining individuals and the forthcorning generations. The summation of costs thus continues until the expected death E(D) of the organism displaying reproductive effort as before, but the benefits may extend indefinitely into the future, albeit presumably having been brought to negligible Ievels through the discounting process,53 and this summation thus extends potentially to infinity. Reproductive effort can therefore be assumed to maxirnise net reproductive value (NRV)- which again is the equivalent of the econornist's net present value applied to reproductive effort- as follows: max NRV "

t(

e(ri i I) gcsi I) )+

nRE = j

~ 1

+ . . . +

[5.8]

1 + di

L( j:

gcci 1> + dj I

1

I

t(

j • 1

(1

e(ri i 2) gc_si z) +

di

1)

(1

+

)

di 2)

t (ri i .) gcsi ..) ) 1 (1 + di 1)(1 + di 2) ... (1 + di .)

gcci 2> (1 + dj 1)(1 + dj 2)

~Ci E(D))

53 These discounting factors are intended to be as concrete as those goveming the tree's growing and shedding of leaves considered above with respect to somatic effort. lt may appear that because the self-perpetuating kin vehicle may extend indefinite1y into the future these discount factors wou1d be less important than for individual vehicles, but that would be to overlook the essence of "the economy of nature": genetic replicators in all vehicles are implicitly or explicitly in competition with other genetic replicators, and it is this which provides the general necessity for discounting. If for example kin-group A reproduces on average every t + 1 periods, whereas kin-group B is otherwise identical but reproduces every t periods, then over evolutionary time B will come to dominate the gene pool.

136

V. From Psychology to Behaviour

Reproductive effort can be divided into fundamental categories that vary systematically over typical life phases, and figure 5.1 (page 119) shows a hypothetical human lifetime with changing Ievels corresponding to mating, parental investment, and extraparental nepotism. 54 Mating effort involves relationships with sexual partners who are generally not close genetic relatives, but whose contribution is necessary for successful reproduction. In this case the expected benefit term:

L

j • I

E(r1i

1)

2"(B; 1)

refers not to the mate, but to the j 1, j 2, j 3, • • • , j" offspringthat are expected to result from successful mating. Actual benefits are very often received by the mate, but these are interpretable in terms of the economist' s concepts of derived demand or necessary investments. The benefits that were relevant to the selection for mechanisms in the EEA were those which led to the increased survival of genetic replicators, i.e., the offspring rather than the mate. Parental investment involves by contrast the direct transfer of resources between genetic relatives, from the parents who have built up somatic resources during their lifetimes, to the independent offspring. This dependence is most manifest at the earllest stages of life, in the first cell divisions after conception and the subsequent development in the mother's uterus, but in humans may continue for decades. Like all the other forms of effort, parental investment is valued in terms of "opportunity cost", and is defined by Trivers as: Any investment by the parent in an individual offspringthat increases the offspring 's chance of surviving (and hence reproductive success) at the cost of the parent's ability to invest in other offspring. So defined, parental investment includes the metabolic investment in the primary sex cells but refers to any investment (such as feeding or guarding the young) that benefits the young.55

The third form of reproductive effort is extraparental nepotistic effort, which is expended "on behalf of collateral or nondescendant relatives and descendants

54 The following discussion draws upon the analysis of effon in Alexander, Moral Systems, esp. pp. 40-42, 81-88. Alexander provides a detailed typology of the subcategories of somatic and reproductive effort in table 2.1 p. 83, but as in fig. 1.2 omits an explicit category of group effort. 55

Trivers, 'Parental Investment', p. 139 [emphasis in the original].

2. Kin-Group Maximisation

137

other than offspring". 56 Into this category comes behaviour which is typically interpreted as 'kin selection' in the biologicalliterature, such as costs accepted on behalf of siblings. The investigation of the cognitive programs underlying mating effort has been a particularly active area of evolutionary psychology, with biological theory offering testable hypotheses and clear contrasts with non-evolutionary approaches, such as the existence of systematic differences between the sexes. As Buss remarks: As the core of evolutionary theory may be traced to differential gene replication, evolutionary theorizing should be most relevant to those psychological processes surrounding reproductive behavior. If evolutionary theory affords few specific predictions, little understanding of known facts, and no clear guides to phenomena relevant to human reproduction, then its applicability to psychological phenomena distant from reproduction will be doubtful.s7

The following sections discuss both strictly psychological investigations of the psychological structures instantiating reproductive effort, and analyses where the underlying mechanisms are inferred from observed behaviour. b) Sexual Preferences

The discussion of sub-functional variation above (page 16) indicated that the reason for the emergence of sexual reproduction was that it induced differences between the genetic replicators of each parent and their offspring, substantially raising the survival chances of the latter. As such advantages arise through the random mixing of members of the gene pool, and kin by definition have higher than average proportions of genetic replicators in common, a prediction of evolutionary theory is that humans will avoid mating with close kin. Natural selection in the environment of evolutionary adaptedness can be expected to

s6 Alexander, Moral Systems, p. 61. s? David M. Buss, 'Sex Differences in Human Mate Selection Criteria: An Evolutionary Perspective' in Charles Crawford, Martin Smith, and Dennis Krebs (eds), Sociobiology and Psychology: ldeas, /ssues and Applications, pp. 335-351 (Hillsdale, NJ: L_awrence Erlbaum Associates, 1987) p. 336 [hereafter Buss, 'Evolutionary Perspective'). Seegenerally David M. Buss, 'Mate Preference Mechanisms: Consequences for Partner Choice and Intrasexual Competition' in Jerome H. Barkow, Leda Cosmides, and John Tooby (eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, pp. 249-266 (Oxford: Oxford University Press, 1992).

138

V. From Psychology to Behaviour

have led to cognitive programs for such discrirnination, because of the increased survival of genetic replicators resulting from the creation of viable offspring. An early version of this hypothesis was put forward by Westermarck at the end of last century, who proposed that the psychological mechanisms underlying such behaviour operate by reducing the sexual attractiveness of those who, as young children, were in close and frequent contact with the focal individual. 58 Despite the opposition to Westermarck's hypothesis of most sociological and anthropological theories in the intervening decades, empirical research has generated strong support for such a mechanism. 59 One example is Wolfs study of the contrasting "rninor" and "major" forms of Taiwanese marriage, where in the former the bridal pair are raised tagether in sim-pua as children, whereas in the latter they first meet on their wedding day. His prediction that the "rninor" form would be characterised by higher rates of divorce or extramaritat relations, and lower fertility, was upheld by data from hausehold registration records and informant reports. Approximately one quarter of the 132 "rninor" marriages - as compared to only 1.2 per cent of the 171 "major" marriages __:__ ended in divorce or separation, and sirnilarly significant results in the predicted directions were found for adultery and fertility. 60 Further evidence supporting the existence of the Westennarck effect is presented in Shepher's study of Israeli kibbutzim, McCabe's of patrilateral parallel cousin marriages, and Parker and Parker' s of father-daughter sexual relations. 61

58 Edward A. Westermarck, The History of Human Marriage (New York: Macmillan, 1891). 59 Seegenerally Nancy Wilmsen Thornhill, 'The Evolutionary Significance of Incest Rules' Ethology and Sociobiology 11(2) (March 1990): 113-129, esp. p. 114 ff; Nancy Wilmsen Thornhill, 'An Evolutionary Analysis of Rules Regulating Human lnbreeding and Marriage' Behavioral and Brain Seiences 14:2 (1991): 247-293; Clive V.J. Welham, 'Incest: An Evolutionary Model' Ethology and Sociobiology 11(2) (March 1990): 97-111.

60 Arthur P. Wolf, 'Childhood Association and Sexual Attraction: A Further Test of the Westermarck Hypothesis' American Anthropologist 72(3) (June 1970): 503-515, pp. 511-513.

61 Joseph Shepher, lncest: A Biosocial View (New York: Academic Press, 1983 ), esp. pp. 56-62; Justine McCabe, 'FDB Marriage: Further Support for the Westermarck Hypothesis of the Incest Taboo?' American Anthropologist 85(1) (March 1983): 5C-69, esp. pp. 57-64; Hilda Parkerand Seymour Parker, 'Father-Daughter Sexual Abuse: An Ernerging Perspective' American Journal of Orthopsychiatry 56(4) (October 1986): 531-549, esp. pp. 539-541.

2. Kin-Group Maximisation

139

The W estermarck effect shapes the sexual preferences of males and females in a similar way, but many of the hypotheses derived from evolutionary theory relate to sex-specific preferences. A central difference between males and females is the high minimum Ievels of parental investment faced by females, discussed in the context of anorexia nervosa and infanticide above. Male parental investment in the environment of evolutionary adaptedness could have significantly reduced the net costs over time to a woman bearing a child, and female mate preferences are thus expected to give high weights to the current and expected somatic resources of males, and the willingness to commit these to the partnership and offspring. In the modern world a prime measure of somatic resources is financial capacity, and Buss examined this prediction in a major cross-cultural study involving 10,047 observations arranged in thirty-seven samples which were drawn from six continents and five islands, concluding that: Fernales value the financial capacity of potential mates more than males do. Ambition and industriousness, cues to resource acquisition, also tend to be valued more heavily by females across cultures.62

Males in contrast face a much lower minimum parental investment, and as argued in the context of the "young male syndrome", can be expected to have achieved maximum reproductive success in the EEA through achieving access to multiple wives or sexual partners. Such a process presupposes a typical male preference for more than one mate, and Symons, after a review of the evidence, has concluded that this is in fact so.63 c) Male Reproductive Strategies

Reproductive strategies are systems of inter-related forms of behaviour that maximised the expected retums from reproductive effort over time in the environment of evolutionary adaptedness: 62 Buss, 'Evolutionary Perspective', p. 12. "Support was strong for the financial capacity prediction (36 of 37 samples), and moderate for the ambition-industriousness prediction (29 of 37 samples)" (ibid.). 63 The detailed evidence is presented in Symons, Human Sexuality, esp. pp. 206-252, 292-305, and includes the "Coolidge Effect"; the "phenomenon of male arousal by a new female" (p. 209); statistical evidence for greater numbers of extramarital partners by men (pp. 213-215); characteristics ofnon-marital sexuality (pp. 215-223); sexualjealousy (pp. 226-250); and the typically contrasting sexualities of homosexual men and lesbians (pp. 292-305). More recent research is reviewed in Symons, 'Evolutionary Approach', esp. pp. 112-117.

140

V. From Psychology to Behaviour

A reproductive strategy is a program for the allocation of reproductive effort. When to reproduce? With what expenditure of effort? And how shall this expenditure of effort be distributed?64

A strategy may thus be made up from several patterns of behaviour or 'tactics', of which one or more may be expressed by any particular individual depending upon characteristics such as the developmental trajectory that was followed or the characteristics of the current environment. Thornhill and Thornhill have concluded that: The conditional reproductive strategy of male humans in industrial societies primarily consists of [the) seven altematives.65

These tactics, which need not be exclusive, are as follows: 1. 2. 3. 4. 5. 6. 7.

Pairbonding With Parental Care of Male' s Children Pairbonding With Aid of Mate's offspring or Mate Copulation With Material Benefit Provision Seduction-Deception Copulation Without lmplicit or Explicit Commitment Avunculate Rape66

This ranking is in the order of the expected net return to the various tactics, with decreasing 'profitability' being generally associated with decreasing paternity confidence and decreasing costs. The preferred tactic of pairbonding, for example, achieves very high paternity confidence through exclusive sexual access, and is also associated with high and sustained Ievels of parental investment. The following four categories correspond to progressively less exclusive sexual access with consequent reductions in paternity confidence, and to decreasing Ievels of resource provision for the mate and offspring. 67 The avunculate is the terrn anthropologists give to the practice of males providing resources to the offspring of female kin, especially sisters. Alexander' s investigation of this phenomenon in terrns of evolutionary theory is an important example of the heuristic value of assuming that the functionality of current behaviour can be directly understood without investigating the

64 Daly and Wilson, Sex, Evolution, and Behavior, p. 41 [original emphasis boldface]. 65

Thornhill and Thornhill, 'Human Rape', p. 164.

66

Ibid., extracted from fig. 7. p. 165.

67

See ibid., p. 165.

141

2. Kin-Group Maximisation

underlying mechanisms. 68 He reasoned that if the social situations faced by males meant that they bad low confidence in their paternity of putative offspring, then a higher return on reproductive effort will have been achieved by investing in sister's children rather than in their 'own' offspring, as shown in figure 5.3.· c:

GI u GI

50

Woman and her offspring

~~------------~~-------------------r5o -ffai'J

"'

Q>I)Q'

0

li 37.5

s.oo

?.rs~.

c

c

.~

~

s

Of't;

s.o,....

II)~

25

37.5

Mother ·s brother becomes sest male relative of previous generation

25

"'c:

GI

GI

(.!) 12.5

12.5

100

75

50

25

0

Percent Likelihood of Paternity Figure 5.3 Genetic Relationships with Putative Offspring69

As a result of this analysis Alexander predicted that: Whenever general living conditions or other society-wide circumstances Iead to a general lowering of confidence of patemity, only a man's sister's offspring, among all possible nephews and nieces, can become his closest relatives in the next generation. Moreover, children in such societies will generally fail to receive intense parental care from their mother's spouse. In consequence, so long as adult brothers and sisters tend to remain in sufficient social proximity that men are capable of

The hypothesis was frrst advanced in Alexander, 'Evolution of Social Behavior', pp. 372-374, and further developed in Alexander, 'Natural Selection and Sociality', pp. 319-329, and Alexander, Human Affairs, pp. 169-175. 68

69 Reproduced, with permission from the Universty of Washington Press and the author, from Alexander, Human Affairs, fig. 9 p. 170; see also Alexander, 'Natural Selection and Sociality', fig. 4 p. 320.

142

V. From Psychology to Behaviour

assisting their sister's offspring, we can predict that a general society-wide lowering of confidence of paternity will Iead to a society-wide prominence, or institutionalization, of mother's brother as an appropriate dispenser of parental benefits.70

This prediction has been supported in the evidence frorn anthropological research which preceded Alexander's explanation,71 andin subsequent investigations specifically designed to test the hypothesis. 72 Thomhill and Thomhill have proposed that psychological rnechanisrns for the least 'profitable' of these seven strategies - rape - were selected in the evolutionary past because of the increases in inclusive fitness thereby gained by rnen who bad no other avenue for reproductive effort, or who used it as a supplernentary route to reproductive success. Rape, frorn this perspective, is the process of rernoving fernale freedorn of choice by forcing copulation, and could have been adaptive in the EEA even if paternity confidence was low, if the cost of raping was low enough. Such a "conditional strategy" hypothesis has achieved notable success in explaining rape in non-human species,73 and is cornpatible with the observation that rapes are especially cornrnon in special

70

Alexander, Human Affairs, pp. 171-172.

71

See the review of the evidence in Alexander, Human Affairs, pp. 172-175.

See e.g., Flinn and Low, 'Mating Patterns', pp. 230-241; Mark F. Flinn, 'Uterine vs. Agnatic Kinship Vatiability and Associated Cousin Marriage Preferences: An Evolutionary Biological Analysis' in Richard D. Alexander and Donald W. Tinkle (eds.), Natural Selection and Social Behavior: Recent Research and New Theory, pp. 439-475 (New York: Chiron Press, 1981), pp. 441-447. 72

73 R. Thomhill has demonstrated that scorpionflies possess a conditional strategy, adopting one of three ranked reproductive strategies depending upon the resources they possess: "the Iabaratory and field experiments reveal that males of Panorpa prefer to use dead arthropod presentation over saliva presentation. Males only resort to forced copulation when the two other alternatives cannot be adopted because of resource scarcity." Randy Thomhill, 'Panorpa (Mecoptera: Panorpidae) Scorpionflies: Systems for Understanding Resource-Defense Polygyny and Alternative Male Reproductive Efforts' Annual Review of Ecology and Systematics 12 (1981): 355-386, p. 370. See also Randy Thornhill, 'Rape in Panorpa Scorpionflies and a General Rape Hypothesis' Anima/ Behaviour 28 (1980): 52-59; William Cade, 'Alternative Male Reproductive Behaviors' Florida Entomologist 63(1) (March 1980): 30-42, esp. pp. 41-42; David P. Barash, 'Sociobiology of Rape in Mallards (Anas platyrhynchos): Responses of the Mated Male' Science 197(4305) (19 August 1977): 788-789.

2. Kin-Group Maximisation

143

social situations associated with low expected costs, such as in times of civil disturbance and war. 74 Thornhill and Thornhill hypothesised that in stable societies with substantial penalties for rape such as the United States, rape will be "employed by men who are unable to compete for the resources and status necessary to attract and reproduce successfully with desirable mates". 75 The segments of the population who are expected to be least successful in this competition for somatic resources are expected to correspond closely to those exhibiting the "young male syndrome", who are assumed to pursue high-risk strategies in reproductive effort in addition to their pursuit of resources and status. This prediction was strongly upheld in evidence of the age distributions and socioeconornic status of rape arrestees. 76

74 The expected costs of rape are emphasised by Shields and Shields (William M. Shields and Lea M. Shields, 'Forcible Rape: An Evolutionary Perspective' Ethology and Sociobiology 4 (1983): 115-136). See also Symons, Human Sexuality, p. 280. The rape research reported here infers the underlying cognitive structures from observed behaviour, and Thornhill and Thomhill have more recently directed their research to the nature of the cognitvie processes themselves, e.g. Nancy Wilmsen Thomhill and Randy Thornhill, 'An Evolutionary Analysis of Psychological Pain Following Rape: I. The Effects of Victim's Age and Marital Status' Ethology and~ Sociobiology 11(3) (May 1990): 155-176; Nancy Wilmsen Thomhill and Randy Thomhill, 'An Evolutionary Analysis of Psychological Pain Following Rape: li. The Effects of Stranger, Friend, and Family-Memeber Offenders' Ethology and Sociobiology 11(3) (May 1990): 177-193; Nancy Wilmsen Thomhill and Randy Thornhill, 'An Evolutionary Analysis of Psychological Pain Following Rape: Ill. The Effects of Force and Violence' Aggressive Behavior 16 (1990): 297-320; Nancy Wilmsen Thomhill and Randy Thomhill, 'An Evolutionary Analysis of Psychological Pain Following Human (Homo sapiens) Rape: IV. The Effect of the Nature of the Sexual Assault' Journal of Comparative Psychology 105(3) (September 1991): 243-252; Randy Thomhill and Nancy Wilmsen Thomhill, 'The Evo1utionary Psychology of Men's Coercive Sexuality' Behavioral and Brain Seiences 15(2) (June 1992): 363-421 [hereafter Thomhill and Thomhill, 'Coercive Sexuality']. As Palmer notes, a narrow view of evolutionary psychology that largely ignores behaviour may be less successful than a broader perspective that may include, for example, comparisons between species (Palmer, 'Darwinian Psychology', esp. p. 296; seealso Alexander, 'Epigenetic Rules', esp. p. 253). 75

Thornhill and Thomhill, 'Human Rape', pp. 137-138.

Thornhill and Thornhill ('Human Rape'), using 1974 and 1975 aggregate U.S. data, show that rape arrestees are significantly younger than the general male population (fig. 5 p. 149, D = 0.240, p < 0.001), and that this age distribution is very sirnilar tothat for robbery and murder (fig. 6 p. 151). On a basis of their Iiterature review they conclude "that young men seem to predominate among rapists is also indicated by all 76

144

V. From Psychology to Behaviour

Although the situation of low-status men may Iimit their available reproductive tactics and make them relatively insensitive to the costs of rape, there is no such restriction on the choice of actual rape victim. It is thus to be expected that the characteristics of females actually raped would correspond to those associated with the highest expected benefit to the kin-group vehicle in the environment of evolutionary adaptedness, which would have varied markedly with the fertility of the rape victim. This implies that rapists will exhibit preferences for victims from age groups which corresponded to the highest fertility in the EEA, i.e., women aged between puberty and the late twenties. Figure 5.4 shows the age distribution of rape victims in comparison to the female population, and clearly supports this prediction. These typical rape victim and rapist characteristics not only support the hypothesis that rape is the result of psychological processes that maximised inclusive fitness in the EEA, but can be used to discriminate between competing explanations of rape. Having conducted an extensive Iiterature search Thornhill and Thomhill found few well-specified and testable hypotheses, but concluded that: There are two general views of rape identifiable in the social science literature: frrst, that rape is a social pathology which stems from the complexity of modern industrial societies; and secondly, rape is an act used by men to dominate women. The social pathology hypothesis primarily restricts rape to industrial societies. This prediction is false. Rape is probably cross-cultural and universal. . .. The feminist hypothesis seems to predict that men will rape powerful older women.48 This is false. Rape is directed primarily at young, poor women. 49 The feminist view would also predict that rapists will derive equally from all walks of life and adult age categories. This appears to be false in all human societies for which there are data. "

But see L. Ellis and C. Beattie, 'The fetttinist explanation for rape: an empirical test', Journal of Sex Research 19 (1983), pp. 74-93.

•• Thornhill and Thornhill, 'Human Rape•77

major studies of rape offenders by social scientists" (p. 148). In investigating status they examined three detailed sociological analyses of rape offenders in the United States and concluded "poor men seem to be the rapists. Data suggest that rape offenders in the United States most often derive from lower socioeconomic backgrounds and are poorly educated." (p. 150). Further data supporting this prediction was presented from other societies, including Denmark, Australia, and the Gusii in the highlands of Kenya (pp. 153-154), and from Black and Chicano ethnic groups within the United States (pp. 153-152). 77 Randy Thomhill, Nancy Wilmsen Thomhill, and Gerard Dizinno, 'The Biology of Rape' in Sylvana Tomaselli and Roy Porter (eds.), Rape (Oxford: Basil Blackwell,

145

2. Kin-Group Maximisation

....•... -

~ 15

ID

~

5

II

u

n

••

n•au

50 AlE IYIUSI

..

71

.

••

•••

Figure 5.4 Percent Rape Victirns and Percent Fernales in the Population in Relation to Fernale Age78

1986), pp. 16-40 at p. 116, endnotes p. 260. For a collection of ferninist criticisrns of evolutionary explanations of rape see Suzanne R. Sunday and Ethel Tobach, (eds.), Violence against Warnen: A Critique of the Sociobiology of Rape (New York: Gordian Press, 1985), and general criticisms and an extended bibliography aretobe found in the peer commentary to Thornhill and Thornhill, 'Coercive Sexuality'. 78 Reproduced, with permission from Elsevier Science Publishers BV and the authors, from Thornhill and Thomhill, 'Human Rape', fig. 1 p. 143. The original caption continues "data areplottedas midpoint of the following age classes: 12-15, 16-19, 20-24, 25-34, 35-49, 50-64, 65-99. N = 10,315 rape victirns. Data from police records in 26 U.S. cities, 1974 and 1975 (U.S. Dept. Justice, 1979) [United States Department of Justice, Rape Victimization in 26 American Cities, Report from the Law Enforcernent Assistance Administration (L.E.A.A.), National Criminal Justice Information and Statistics Service (Washington, DC.: U.S. Govt. Printing Office, 1979)]. Fig. 5.4 should be interpreted in terms of comparisons between the two distributions rather than as general demographic pattems, because of the uneven age classes. This introduces no

10 Elworthy

146

V. From Psychology to Behaviour

Alexander's research on the avunculate and Thornhill and Thornhill's on rape thus support the hypothesis that males possess cognitive processes which instantiate conditional reproductive strategies. The expression of particular behavioural 'tactics' is dependent upon individual characteristics (such as the possession of somatic resources), and the external environment (such as the existence of sister' s offspring as routes for extra-parental nepotistic investment). These hypotheses are better specified and more compatible with the empirical evidence than alternative theories advanced in the sociological and anthropological literature. They further support the theoretical perspective that humans, like other species, possess psychological processes which induce the acceptance of costs in the process of maximising what was the expected contribution to the survival of genetic replicators in the environment of evolutionary adaptedness. In current environments this ultimate 'purpose' may not be achieved, but the mechanisms still lead to altruistic behaviour towards those identified as kin, and to 'irrational' reproduction-orientated behaviour towards potential sexual partners. I believe that it is but a small conceptual step from these results to their equivalents for the group vehicle, as discussed in the next section. 3. Group Maximisation a) Specification of Group Maximisation It has been argued in chapters II and III that adaptations for the group vehicles are similar in principle to those for kin-groups, in that as supraindividual entities both exert influence through their constituent organisms rather than directly. The major conceptual difference between the two forms of maxirnisation is the replacement of the coefficient of relationship r1 i with the correlation of relatedness between an individual and the recipient or recipients of the benefits to the the group F1 k. 79 The effort by an individual for the group is termed community effort CE, so that the contribution of the group

bias for statistical tests of the differences between the distributions which "differ significantly (X2 = 10,879, p < 0.001, df= 6; Kolmonogorov Smirnov D = 0.42, p < 0.001)" (ibid., p. 143). 79 Although there may be low variance in K between typical members of the group, it is to be expected that there will be occasional exceptions, associated in particular with new entrants to the group, and it is thus necessary to retain the subscripts and include K within the summations rather than leaving it as a constant outside.

3. Group Maximisation

147

vehicle to the survival of the genetic replicators is denoted ~WcE• and the benefits are now summed over the m recipients k 1, k2, k3, ••• ,km. Following the farniliar pattem of equations 5.1 to 5.4 (pages 114-118), and equations 5.5 to 5.8 (pages 134-135), ex post maximisation is specified for the environment of evolutionary adaptedness: Ir!

[5.9]

max

~ Wa

=

L

k • l

(Ftk Bk) - Ct

This is extended to an a priori specification of the expected contribution of a typical individual's community effort in the EEA. For similar reasons as those given for the coefficient of relationship, the coefficient of relatedness is given a separate expectations term, e(F 11J, so that the resulting expression is: [5.10]

max

tJ.. WE

=

.

L

k • l

t (F1 *)

E(Bt) - E(C1 )

Similarly, for maximisation in a new space in the present denoted by equation 5. 7 (page 135) is transformed into: [5.11]

max

1tE!CEJ•

m

7tE =

L

k . l

t(F1 k)E(B*)- E(C1)

The group vehicle is also similar to the kin-unit vehicle in that the Iimit of its influence cannot be a priori specified and is theoretically infinite. Following the reasoning applied in the derivation of equation 5.8 (page 135), the net community value NCV of effort by a representative individual on behalf of the group is represented as:

Despite these analytical similarities between reproductive and community effort, there exist fundamental practical differences between the two, which have

!O•

148

V. From Psychology to Behaviour

led to the possibility of the existence of behaviour for the group to be discounted or dismissed: If biologists are correct, all that philosophers refer to as altruistic or utilitarian

behavior by individuals will actually represent either the temporary altruism (phenotypic beneficence or social investment) of indirect somatic effort or direct and indirect nepotism. The exceptions are what might be called evolutionary rnistakes or accidents that result in unreciprocated or "genetic" altruism, deleterious to both the phenotype and genotype of the altruist. 80

Understanding these differences is helped by assuming that human encephalisation and group selection for cognitive processes were both the result of hominid balance of power processes, which may have represented "an almost ideal model for potent selection at the group level". 81 The characteristics selected for were those that led to intra-group cooperation for inter-group competition, and two types of group-selected mechanism may therefore be theoretically distinguished, although in practice a continuum almost certainly exists. The first category is for individual cooperation within the society, but such behaviour is both closely connected to somatic and reproductive effort, and in all probability subject to less powerful selection than the genet and kin-group vehicles. The expectation therefore arises that if such forms of community effort exist, they are unlikely to cause major and overt conflicts with the somatic and reproductive effort, because that would not be evolutionarily stable in competition with the genetic replicators for traits for these 'lower' vehicles. They are, by contrast, to be looked for in 'underlying' cooperation that is so 80 Alexander, Moral Systems, p. 88. Community effort in the environment of evolutionary adaptedness was not deleterious to the genotype, but because of the exclusion of a role for group selection and the group vehicle, Alexander perceives this as following from the absence of benefit for the genet and kin-group vehicles. I have anempted to avoid the word "altruism" as far as possible, together with terms like "rationality", "irrationality", "selfishness", "pathological", and so on, because of their strong normative associations. It will be hypothesised below that the psychological capacities for "altruism" resulting from group selection during the balance of power processes underpin the most repellent of human actions: genocide, war, racism, ethnocentrism, and related behaviour. It may be that those who have been most active in claiming recognition for human "altruism", and in criticising the "self-interest" of economics and biology, find that they prefer "selfish" behaviour to such forms of community effort. 81

IV.4.

Alexander and Borgia, 'Levels of Organisation', p. 470. See generally section

3. Group Maximisation

149

society- or species-typical that it is hardly remarked upon. This is analogous to the hypothesis advanced earlier, that sexual reproduction results from species selection for traits that were effective against parasites: the "gavotte of the chromosomes" may be costly for particular genets and kin-groups, but cannot be altered through selection. In the second category are the mechanisms underlying community effort for behaviour in the context of inter-group competition, especially in the form of war and other forms of group violence. Because selection can be expected to have acted for domain-specific cognitive faculties that only produced such behaviour in particular situations. As here the potential benefits to the group could have been very high, such as through preventing extinction, these traits are expected to be clearly advantageous to the group in contrast to the kin-group or individual. An essential element for group success in such situations would appear to be mechanisms which give group unity, so that 'it' can behave in a coordinated fashion in the face of an external threat. The following sections report evidence for psychological characteristics that appear to contribute to such unity, which is followed by a discussion of research on cooperation within the group, and an analysis of these empirical results in terms of group maxirnisation.82 b) Obedience

Milgram's fundamental experimentaldesignwas based on the principle that procedures that force subjects to act in a certain way are more valid than hypothetical written or oral responses, and that subjects from a wide variety of age groups and social classes would provide more reliable results than the university students often used in psychological studies. The hypothesis on which the actual experiments were based was that the power of an authority in achieving obedience could best be investigated by opposing a destructive form

82 This follows the pattern of Milgram's work on which this section is largely based. His original research was largely empirical, being "derive[d], in the frrst instance, from direct observation of a social fact; the individual who is commanded by a legitimate authority ordinarily obeys. It is a ubiquitous and indispensable feature of social 1ife." Stanley Milgram, 'Behavioral Study of Obedience' Journal of Abnormal and Social Psychology 67(4) (October 1963): 371-378, at p. 371 [hereafter Milgram, 'Behavioral Study of Obedience'). Milgram later provided a comprehensive exp1anation of the results, in Stanley Milgram, Obedience to Authority: An Experimental View (New York: Harper & Row, 1974), pp. 123-164 [hereafter Milgram, Obedience to Authority].

150

V. From Psychology to Behaviour

of obedience with generally accepted moral nonns. This was achieved in the initial experiment by each naive subject being ordered by an "experimenter" to administer increasingly more powerful electric shocks to a "leamer" in the context of a leaming experiment. 83 The pressure of conforming to the demands of the experimenter was thus set as a counterlog force to the increasing pressure to disobedience as the shocks to the leamer became increasingly hannful. The leamer behaved in an appropriate manner as the subject increased the indicated voltage of the shocks administered in thirty steps from "Slight Shock" (15 to 60 volts) to "Danger: Severe Shock" (375-420 volts) and "XXX" (435-450 volts). The basic setting of the experiment, showing the locations of the participants in this initial experiment, is shown in figure 5.5.

Learner

Experimenter

Figure 5.5 Location of Participants in the Initial Obedience Experiment84 83 The details of the method and apparatus used and characteristics of the subjects are reported in Milgram, 'Behavioral Study of Obedience', pp. 371-374. The "experimenter" (or teacher) and "leamer" (or victim) were both Milgram's confederates. 84 Reprinted, with permission from Harper & Row and Mrs Alexandra Milgram, from Stanley Milgram, Obedience to Authority: An Experimental View (New York: Harper &

3. Group Maximisation

151

The subject' s response was interpreted as obedient until he or she broke off the learning experiment and stopped shocking the victim, thereby disobeying the experimenter. Although this verbal reconstruction and figure 5.5 may make the situation appear transparent for the naive subjects, they were - with few exceptions - convinced of the reality of the shocks they delivered. 85 Many showed physiological and behavioural characteristics consistent with high and even extreme Ievels of tension. 86 The results of this initial experiment diverged sharply from the predictions of both psychiatrists and members of the general population, who expected that most subjects would break off at "Very Strong Shock" (195-240 volts), and who predicted that "virtually all subjects will refuse to obey the experimenter; only a pathological fringe, not exceeding one or two per cent, was expected to proceed to the end of the shockboard".87 However: Upon command of the experimenter, each of the 40 subjects went beyond the expected breakoff point. No subject stopped prior to administering Shock Level 20.

Row, 1974 ), fig. l3 p. 91. This illustration has the caption, "Leamer demands to be shocked" in the original, because it is used as an illustration in the section on role permutations. lt shows accurately the location of the participants in the initial experiments, however, and I find it clearer than the photographs that Milgram used to frrst explain the experiment (ibid. fig. 3 p. 25). 85 "Subjects were asked: 'How painful to the leamer were the last few shocks that you administered to him?' Subjects were instructed to indicate their answers on a printed 14-point scale ranging from 'Not at all painful' to 'Extremely painful.' The modal response was 14 (Extremely painful) with the mean at 13.42." Milgram, 'Behavioral Study of Obedience', p. 375. Readers who wish to gain a closer appreciation for these experiments are encourage to view Milgram's film (Stanley Milgram, Obedience (A Filmed Experiment) (New York: Distribution through the New York University Film Library, 1965)). 86 "In a large number of cases the degree of tension reached extremes that are rarely seen in sociophysical laboratory studies. Subjects were observed to sweat, tremble, stutter, bite their lips, groan, and dig their fingemails into their flesh. These were characteristic rather than exceptional responses to the experiment. One sign of tension was the regular occurrence of nervous laughing fits. Fourteen of the 40 subjects showed definite signs of nervous laughter and smiling. The laughter seemed out of place, even bizarre. Full-blown, uncontrollable seizures were observed for 3 subjects. On one occasion we observed a seizure so violently convulsive that it was necessary to call a halt to the experiment." Milgram, 'Behavioral Study of Obedience', p. 375. 87

Milgram, Obedience to Authority, p. 31, see generally pp. 27-31.

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(At this Ievel - 300 volts - the victim kicks the wall and no Ionger provides answers to the teacher's multiple-choice questions.) Of the 40 subjects, 5 refused to obey the experimental commands beyond the 300volt Ievel. Four more subjects administered one further shock and then refused to go on. Two broke off at the 330-volt Ievel, and 1 each at 345, 360, and 375 volts, Thus a total of 14 subjects defied the experimenter.88

Hence twenty-six of the forty subjects followed the instructions through to the maximum of 450 volts, two Ievels past the "Danger: Severe Shock" category, and remained obedient until the experimenter brought the Iearning experiment to an end. Nineteen variations on this basic experimental structure were conducted by Milgram, revealing consistent pattems in behaviour. 89 The authority of the experimenter was shown to derive from bis professional position rather than bis personal characteristics, and obedience to bis authority dropperl rapidly when he was not physically present in the laboratory. 90 Reductions in obedience also accompanied the increasing physical proximity of the learner; when an ordinary man who appeared to be a subject ordered the shock Ievels; when two experimenters were present who disagreed at a specific point; and when the authority agreed temporarily to play the role of the victim. 91 By contrast, comparatively little variation resulted whether the subjects were male or female, whether the victim attached a contractual Iimitation to bis participation or not, or whether the laboratory' s context was that of a prestigious university or an unknown "research institute".92 A control experiment without any authority showed that subjects on their own generally chose very low shock levels.93 These results provide consistent and replicable evidence of an

88

Milgram, 'Behavioral Study of Obedience', p. 375.

The shock Ievels at which the subjects were disobedient are shown in Milgram, Obedience to Authority, tables 2, 3, 4, and 5 (pp. 34, 60-61, 94-95, 119). 89

90

lbid., experiment 6 pp. 58-59; experiment 7 pp. 59-62.

/bid., experiments 1-4 pp. 32-43, experiment 13 pp. 93-97, experiment 15 pp. 105107, experiment 14 pp. 95-104. This last variation brought a dramatic change in behaviour of the naive subjects: "At the frrst protest of the shocked experimenter, every subject broke off, refusing to adrninister even a single shock beyond this point. There is no variation whatsoever in response. Further, many subjects literally leapt to the aid of the experimenter, running into the other room to unstrap him" (ibid., p. 103). 91

92

/bid., experiments 8-10 pp. 62-40.

93

Ibid., experiment 11 pp. 70-72. A further form of control, in which subjects

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extraordinary human relegation of 'normal' moral standards when subject to command by authority, and parallel the relegation of 'normal' standards of perception in situations of group pressure exarnined in the next section. c) Conformity

Important early research into conformity94 was conducted by Asch in a series of experiments in which the naive subjects were placed in groups of seven to nine with other college students, and all were asked to compare the lengths of three lines on a card with a reference line segment.95 All of the members of the group except the naive subject were confederates of Asch, and bad been instructed to systematically give false answers. As in the obedience experiments two opposed forces were brought to bear on the subject: the evidence of his eyes, and the unanimous opinion of the other members of the group, his apparent peers.96 The results were striking: Whereas in ordinary circumstances individuals matehing the lines will make mistakes less than 1 per cent of the time, under group pressure the minority subjects swung to

predicted their responses, revealed that they reflected the attitudes of the psychiatrists and unanimously believed themselves capable of early disobedience. See Stanley Milgram, 'Liberating Effects of Group Pressure' Journal of Personality and Social Psyclwlogy 1(2) (February 1965): 127-134 {reprinted in Stanley Milgram, The Individual in a Social World: Essays and Experiments, pp. 188-199 (Reading, MA: Addison Wesley, 1977)}, table 1 p. 129 {p. 190} [hereafter Milgram, 'Liberating Effects']. 94 Conformity is a broad term, meaning "compliance in actions, behaviour, etc., with certain accepted standards or norms" (Collins Dictionary, s.v. "conformity"). In this discussion it is limited to behaviour which camplies with the actions of peers who have a similar status and no special authority over the individual concemed. 9~ Solomon E. Asch, 'Effects of Group Pressure upon the Modification and Distortion of Judgement' in Harold Guetzkow (ed.), Groups, Leadership, and Men, pp. 177-190 (Pittsburgh: Camegie Press, 1951); Solomon E. Asch, 'Opinions and Social Pressure' Scientific American 193(5) (1955): 31-35 [hereafter Asch, 'Opinions and Social Pressure' ]; Solomon E. Asch, 'Studies of Independence and Conformity: I. A Minority of One Against a Unanimous Majority' Psyclwlogical Monographs 9: entire 146 (1956): 258-90. Solomon E. Asch, Social Psychology, [1952] paperhack ed. (Oxford: Oxford University Press, 1987), pp. 451-501 [hereafter Asch, Social Psychology]. See also R.S. Crutchfield, 'Conformity and Character' American Psychologist 10 (1955): 191-198; Robert R. Blake and Jack W. Brehm, 'The Use of Tape Recording to Simulate a Group Atmosphere' Journal of Abnormaland Social Psychology 49 (1954): 311-313. 96 Asch, 'Opinions and Social Pressure', p. 34. All the subjects in this frrst experiment were male Harvard students, hence the use of the masculine pronoun.

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acceptance of the misleading majority's wrong judgements in 36.8 per cent of the selections.97

In order to reveal the influences upon this conformist behaviour, variations were made which systematically varied the size of the group from two to fifteen. A clear trend resulted, with one 'opponent' producing little effect, two causing 13.6 per cent wrong answers, and three 31.8 per cent, but little change resulted from increasing the group size further. 98 Further experiments examined the effects of reducing the unanimity of the group, with one 'truthful' partner for the naive subject sharply diminishing the power of the majority. 99 Even the existence of dissenting answers which were not objectively correct served to break the appearance of group conformity, and led to the naive subjects giving far fewer false answers. 100 Asch's experiments provide simple, clear, and replicable ex.amples of the effects of conformity, but they focus on the signals given by the subjects, rather than requiring them to act in a manner that is more than communicative. An investigation of the latter form of "action conforrnity" was conducted by Milgrarn, using a variation of the experiments developed for the investigations into obedience discussed above. 101 Instead of direct authority resulting from the commands of the ex.perimenter, three "teachers" were instructed to choose the shock Ievels themselves. two being Milgram's confederates and the third the naive subject. The experimentwas arranged so that the confederates suggested voltage Ievels first, but the shock actually given was the lowest chosen by any of the three teachers. As the confederates proposed steadily increasing shock

97

lbid., p. 33.

98

lbid., p. 34.

"The majority effect was markedly weakened under these conditions. There were sixteen majority errors (out of a total of 126 estimates), or 13 per cent of the number of estimates. Not only was the amount of yielding reduced, but also the degree to which any single subject yielded diminished strikingly; no one exceeded three errors." Asch, Social Psychology, p. 477. 99

100

Asch, 'Opinions and Social Pressure', p. 34.

Milgram notes that "There is little reason to believe a priori that observations made with regard to verbal conforrnity are automatically applicable to action." Stanley Milgram, 'Group Pressure and Action Against a Person' Journal ofAbnormaland Social Psychology 69(2) (1964): 137-143. {Reprinted in Stan1ey Milgram, The Individual in a Social World: Essaysand Experiments, pp. 178-187 (Reading, MA: Addison Wesley, 1977)}, p. 137 {p. 178} [hereafter Milgram, 'Action Against a Person']. 101

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Ievels the administered shocks were effectively determined by the naive subjects, whose behaviour displayed the consistent pattem shown in figure 5.6. 30

A:

5 B

0

0

5

10

15

20

25

30

Critical trial

Figure 5.6 Mean Shock LevelsinGroup Pressure Experiment102

The average responses were clearly substantially influenced by the group pressure, approximately bisecting the low and stable Ievels chosen when the naive subject could choose the administered shock freely (B), and the increasing values suggested by the two confederates (A). The smoothness of this average result conceals very high individual variances however: On the thirtieth critical trial the most conforming quantile had a mean shock Ievel of 27 .6, while the mean shock Ievel of the least conforming quantile was 4.8.103

102 Reprinted, with permission from McGraw Hili and Mrs Alexandra Milgram, from Stanley Milgram, The Individual in a Social World: Essaysand Experiments, (Reading, MA: Addison Wesley, 1977), fig. 14.1 p. 185. The original caption read: "Mean shock Ievels in experimental and control conditions over 30 critical trials." 103 Milgram, 'Action Against a Person', p. 140 {p. 183}. In this and the following experiment the shocks are referred to in Milgram's reports by Ievels rather than voltages. The Ievel corresponds to the number of the trial, i.e., in trial 30 (the last) the shock

!56

V. From Psychology to Behaviour

Although a large number of background characteristics were recorded, only educational and religious variables were significantly, if weakly, correlated with these differences in conforrnity .104 All the experiments exarnined have considered negative examples of conforrnity, with naive subjects being induced by group pressure to behave in a manner deviating from that which was objectively correct, in the case of the visual comparisons, or socially appropriate, in the shock experiments. The procedural difficulty in investigating positive aspects of conforrnity lies in establishing a 'baseline' from which the naive subjects can be induced to deviate by group pressure. An imaginative solution to this problern was found by Milgram, who used the obedience established in the authority experiments as the baseline and set the group pressure in opposition to the commands of the experimenter, so that the effect of group conforrnity was to encourage disobedience - a positive function. These experiments have the added benefit of focusing attention on the distinction between obedience and conforrnity. The former is characterised by an explicit order in a hierarchical context, resulting in behaviour that is not necessarily irnitative. The latter results from implicit peer group pressure, and is characterised by homogeneaus behaviour within the group. A particularly interesting difference is the explanations that subjects give for their behaviour after the fact: "subjects deny conforrnity and embrace obedience as the explanation of their actions" . 105

suggested by the two confederates was Ievel 30 (the highest), which corresponded to 450 volts. "Background characteristics of the experimental subjects were noted: age, marital status, occupation, rnilitary experience, political preference, religious affiliation, birthorder information, and educational history. Less educated subjects tended to yield more than those who possess a college degree (X2 df = 1 = 2.85, p < .10). Roman Catholic subjects tended to yield more than Protestant subjects (X2 df = 1 = 2.96, p . < .10)." Milgram, 'Action Against a Person', p. 141. 104

105 Milgram, Obedience to Authority, p. 115 [emphasis in the original]. Milgram elaborates on this difference: "In Asch's experiments on group pressure, subjects typically understate the degree to which their actions were influenced by members of the group. They belittle the group effect and try to play up their own autonomy, even when they have yielded to the group on every trial. . . . In the obedience experiment, the reaction is diametrically opposite. Here the subject explains his action of shocking the victim by denying any personal involvement and attributing his behavior exclusively to an extemal requirement imposed by authority." (ibid.).

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Tbe experimental procedure for tbis obedience-conformity experiment was an adaptation oftbat just reported, but instead of tbe "teacbers" being left alone after a briefing by tbe experimenter, tbe latter remained in tbe room and ordered tbem to increase tbe valtage as in tbe obedience experiments. Tbe first confederate refused to obey the experiment after 150 volts bad been administered, and tbe second after 210 volts. As in tbe obedience experiments the naive subject was judged disobedient at the stage when he refused to shock the victim and rejected tbe orders of the experimenter. The results were dramatic: In sum, in the group setting 36 of the 40 subjects defy the experimenter, while the corresponding number in the absence of group pressure is 14. The effects of peer rebellion aremostimpressive in undercutting the experimenter's authority. Indeed, of the score of experimental variations completed in the Y ale study on obedience nonewas so effective in undermining the experimenter's authority as the manipulation reported here. 106

These various experiments thus demonstrate tbat strong influence is exerted through conformity to the implicit pressure of a peer group, which is distinct from, and can be compared to, that following obedience to the commands of a person in authority. An interpretation of these empirical results in terms of community effort is provided in the next subsection. d) Obedience and Conformity as Community E.ffort

The obedience and conformity results from Asch and Milgram are not aberrant Iabaratory phenomena, but characterise immensely important and real aspects of human behaviour. Few readers will need reminding of the importance of individuals setting aside normal individual morality in their obedience to authority: the terrifying bebaviour responsible, for example, for the deaths of vast numbers of Jews, homosexuals, political opponents, and other 'undesirable' minorities in Nazi Germany is probably the most vivid example. Less widely appreciated is the remarkable conformism of many of their victims. An example is Bettelheim's observation of the bebaviour of prisoners who bad become used to conditions (old prisoners) and those who bad recently arrived (new prisoners) at the Dacbau and Buchenwald concentration camps:

106

Milgram, 'Liberating Effects', p. 131 {p. 194).

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V. From Psychology to Behaviour

Weaklings were those most apt eventually to turn traitors. Weaklings usually died during the frrst few weeks in the camp anyway, so it seemed as weil to get rid of them sooner. So old prisoners were sometimes instrumental in getting rid of the unfit, in this way making a feature of Gestapo ideology a feature of their own behavior. This was one of the many situations in which old prisoners demonstrated toughness and molded their way of treating other prisoners according to the example set by the Gestapo. That this was really a taking-over of Gestapo attitudes was seen from the treatment of traitors. Self-protection asked for their elimination, but the way in which they were tortured for days and slowly killed was taken over from the Gestapo. Old prisoners who seemed to have a tendency to identify themselves with the Gestapo did so not only in respect to aggressive behavior. They would try to arrogate to themselves old pieces of Gestapo uniforms. If that was not possible, they tried to sew and mend their uniforms so that they would resemble those of the guards. The length to which prisoners would go in these efforts seemed unbelievable, particularly since the Gestapo punished them for their efforts to copy Gestapo uniforms. 107

Conformity and obedience in daily life are not usually as striking as these examples, but I believe that they play an immense role in 'normal' social behaviour, and that they have been under-emphasised in much social-scientific research due to an undue concentration on 'rational' and self-interested individuals. Conformity and obedience have been interpreted within the general perspective developed here as community effort: individual behaviour resulting from cognitive processes selected in the environment of evolutionary adaptedness because they led to inclusive fitness maximisation through the group vehicle. A group-selectionist explanation of these traits is likely to disturb even those sympathetic to the interpretation of cognitive programs as leading to genet and kin-group maximisation. It is thus instructive to examine the psychological processes involved in obedience to authority, as Milgram's explanation provides an elegant example of how the different perspectives on adaptations may be combined to create a convincing multi-faceted explanation of cognitive

107 Bruno Bettelheim, 'Individual and Mass Behaviour in Extreme Situations' Journal of Abnonnal and Social Psychology 38 (1943): 417-52, p. 448. Unlike the conformity experiments conducted by Asch and Milgram, the 'conformity' of the old prisoners is not clearly distinguishable from obedience, as the characteristics that they imitated were those of a group that had power over them. It is not simply obedience, however, as, for example, the Gestapo forbade the copying of uniforms.

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processes and observed behaviour. 108 Milgram' s results are widely known and respected, 109 yet their interpretation is often sharply criticised, when discussed at all. 110 The essence of Milgram' s view is the recognition of the functionality of obedience for the group in the face of extemal threats: The formation of hierarchically organized groupings lends enormous advantage to those so organized in coping with dangers of the physical environment, threats posed by competing species, and potential disruption from within. The advantage of a

108 The focus is upon obedience to authority, because as discussed above it provides the greatest contrast to somatic and reproductive effort, and because it is the form of behaviour concentrated upon by Milgram, but appropriate amendments should make the analysis applicable to other forms of community effort.

For example: "Milgram's experiments are possibly the best known of all those carried out on the behavior ofhuman beings" (John C. Caiazza, 'Milgram's Experimental View of Authority' Political Science Reviewer 15 (Fall 1985): 261-293, p. 275 fhereafter Caiazza, 'Milgram's Experimental View']); "this is a dassie and controversial study in psychology" Robert E. Omstein, Psychology: The Study of Human Experience (New York: Rarcourt Brace Jovanovich, 1985), p. 625 fhereafter Omstein, Psychology]; "has become perhaps the most widely cited and provocative set of experiments in social science" Arthur G. Miller, The Obedience Experiments: A Case Study of Controversy in Social Science (New York: Praeger, 1986), p. 1 [hereafter Miller, Obedience Experiments]. One of the many surprises I received as a result of teaching in Berlin was that all of my students knew about the Milgram results. On my asking why, they explained that it was compulsory for all students in the (West) German school system to view an adapted film of the experiments. 109

The criticism of psychologists is generally directed at the ethics of Milgram's methodology or their interpretation, rather than the faults with the experiments themselves. See e.g., Robert A. Baron, Donn Byme, and William Griffitt, Social Psychology: Understanding Human Interaction (Boston: Allyn and Bacon, 1976), pp. 17-20 [hereafter Baron, Byme, and Griffitt, Social Psychology]; Mil!er, Obedience Experiments, passim. Criticisms of Milgrams explanation are often dismissive, but rarely founded on empirical refutations or alternative hypotheses; as Miller notes, in one of the few general appraisals of the Milgram's explanation for the behaviour, "In contrast to the voluminous data from the obedience paradigm itself, .. . there is relatively sparse evidence bearing specifically on Milgram's theory" (Miller, Obedience Experiments, p. 232). Caiazza provides one example of such criticisms: "Milgram's high Ievel explanation of obedience is a curious blend of an attitudinal anti-authoritarianism and psychosocial theorizing combined with a clumsy amalgam of various mechanistic formal explanations, including evolutionary, cybemetic, neurological, and chernical" (Caiazza, 'Milgram's Experimental View', pp. 283-284). Bothof the psychology texts mentioned give detailed treatment of the Milgram's experimental results accompanied by illustrations, but fail to discuss Milgram's explanation (Omstein, Psychology, pp. 625-627; Baron, Byme, and Griffitt, Social Psychology, pp. 100-108). 110

160

V. From Psychology to Behaviour

disciplined militia over a tumultuous crowd lies precisely in the organized, coordinated capacity of the military unit brought into play against individuals acting without direction or structure} 11

Milgram does not appear to have been aware of the general rejection of group selection in evolutionary theory in the years preceding publication of his analysis, and views this functionality as having been selected over evolutionary time for the good of the group: A potential for obedience is the prerequisite of such social organization, and because organization has enormous survival value for any species, such a capacity was bred into the organism through the extended operation of evolutionary processes.112

In addition to this explicit recognition of the phylogenetic foundations of obedience, Milgram's appreciation of the domain specificity and the structural complexity of the underlying cognitive processes, together with his appreciation of the variety of ontogenetic factors influencing their development and eventual expression of behaviour, makes the analysis a classic application of the methodology of evolutionary psychology: Indeed the idea of a simple instinct for obedience is not what is now proposed. Rather, we are bom with a potential for obedience, which then interacts with the influence of society to produce the obedient man. In this sense, the capacity for obedience is like the capacity for language: certain highly specific mental structures must be present if the organism is to have a potential for language, but exposure to a social rnilieu is needed to create a speaking man. In explaining the causes of obedience, we need to Iook both at the inbom structures and at the social influences impinging after birth. The proportion of influence exerted by each is a moot point. From the Standpoint of evolutionary survival, all that matters is that we end up with organisms that can function in hierarchies. 113

Having created this basic framework, and having identified the function of obedience for the group, Milgram proceeded to investigate the psychological mechanisms through which it is manifested in individual behaviour. In order to achieve this he developed a type of computational theory: an analysis of the requirements that the achievement of a coherent, hierarchically organised group established for the characteristics of its constituents. Milgram recognised that the key was the relationship between the 'normal' motivation of the individual,

111

lbid., p. 124.

112

lbid. , p. 125.

113

/bid., p. 125 [emphasis in the original].

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161

and the special requirements of the group situation, a point he elucidated with the aid of a cybemetic approach: Whenever elements that function autonomously are brought into a system of hierarchical coordination, changes are required in the intemal structure of the elements. These changes constitute the system requirements, and they invariably entail some suppression of local control in the interest of system coherence. System coherence is attained when all parts of the system are functioning in harmony and not at cross-purposes. 114

The "suppression of local control" in the context of obedience is the setting aside of the individual conscience: From an evolutionary standpoint each autonomously functioning element must be regulated against the unrestrained pursuit of appetites, of which the individual element is the chief beneficiary. The superego, conscience, or some similar mechanism that pits moral ideals against the uncontrolled expression of impulses fulfllls this function. However, in the organizational mode, it is crucial for the operation of the system that these inhibitory mechanisms do not significantly conflict with directions from higherlevel components. Therefore when the individual is working on his own, conscience is brought into play. But when he functions in an organizational mode, directions that come from the higher-level component are not assessed against the intemal standards of moral judgement. Only impulses generated within the individual, in the autonomous mode, are so checked and regulated. 115

This is the only aspect of the explanation that may have to be to be fundamentally modified, because Milgram sees conscience as serving the group through providing the foundations for human sociality, and thus having emerged through group selection. 116 Alexander posits an alternative explanation: that conscience is of direct benefit to the individual vehicle, and is thus one of the large complex of cognitive processes involved in somatic effort: Consciousness and related aspects of the human psyche (self-awareness, selfreflection, foresight, planning, purpose, conscience, free will etc.) are here hypothesized to represent a system for competing with other humans for status, resources, and eventually reproductive success. 117

114

lbid., p. 129.

115

Ibid. p. 129 [emphasis in the original].

116

See ibid., p. 129.

117 Alexander, Moral Systems, p. 112-113. This is closely related to Humphrey's hypothesis that minds make their bearers "nature's psychologists"; see Nicholas K. Humphrey, 'The Social Function of Intellect' in P. Patrick G. Bateson and Robert A.

11 Elworthy

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V. From Psychology to Behaviour

Alexander' s hypothesis implies that a conflict could exist between cognitive processes for obedience, as mechanisms for the group vehicle, and cognitive processes for conscience, for the genet. This would appear consistent with Milgram's observation of the intense personal conflicts feit by the subjects between the demands of their own autonomous consciences, and the demands of obedience to the commands of the authority .118 Should Alexander be

Hinde (eds.), Growing Points in Ethology, pp. 203-216 (Cambridge: Cambridge University Press, 1976) [reprinted in Richard W. Byrne and Andrew Whiten (eds.) Machiavellian lntelligence: Social Expertise and the Evolution of lntellect in Monkeys, Apes, and Humans, pp. 13-26 (Oxford: Clarendon Press, 1988)]; Nicholas K. Humphrey, 'Nature's Psychologists' in B.P. Josephson and V.S. Ramachandran (eds.), Consciousness and the Physical World, pp. 57-80 (London: Pergamon, 1980); Nicholas K. Humphrey, Consciousness Regained: Chapters in the Development of Mind (Oxford: Oxford University Press, 1983), esp. pp. 3-55; Nicholas K. Humphrey, The Inner Eye (London: Faber and Faber, 1986), passim. From this perspective the labelling of evolutionary approaches to cognitive processes as "evolutionary folk psychology" is converted from criticism to praise; see Philip Kitcher, Vaulting Ambition: Sociobiology and the Quest for Human Nature (Cambridge, MA: MIT Press, 1985), pp. 286-288, passim [hereafter Kitcher, Vaulting Ambition]; Philip Kitcher, 'Precis of Vaulting Ambition: Sociobiology and the Questfor Human Nature' Behavioral and Brain Seiences 10(1) (March 1987): 61-71, p. 68. 118 Alexander has examined conscience within the context of complex systems of "indirect reciprocity" which he regards as the foundations for moral systems and human social characteristics: "moral systems are systems of indirect reciprocity. They exist because confluences of interest within groups are used to deal with conflicts of interest between groups" (Alexander, Moral Systems, p. 77). A similar hypothesis developed by Irons stresses the coercive nature of moral codes (William Irons, 'How did Morality Evolve?' Zygon 26(1) (1990): 49-89, esp. pp. 71-80). My approach bears fundamental similarities to those of Alexander and Irons, but they view effort as always resulting in advantages to the genet or kin-group vehicle, whereas mine includes additionally the group vehicle. These hypotheses may be theoretically compared, as in the analysis of underlying forms of cooperation; see Axelrod, 'Evolutionary Approach to Norms'; Karl-Dieter Opp, 'Evolutionary Emergence of Norms' British Journal of Social Psychology 21 (1983): 139-49. In addition they may be empirically assessed and perhaps falsified, with respect to the accuracy of their explanation of observed phenomena such as obedience. What is scientifically unacceptable is an emotional rejection of such arguments, a theme returned to in the next chapter, as in the following cornment by the editor of Ethics to an early exposition of Alexander's argument: "a particular editorial miscalculation was to allow seventy-four pages to Richard Alexander for the kind of half-baked philosophy and recycled sociology that rightly gives sociobiology a bad name." Brian Barry, review of The Roots of Ethics: Science, Religion, and Values, ed. by Daniel Callahan and H. Tristtarn Englehardt, and Ethics in

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correct, then in a topsy-turvy of conventional moral conceptions, conscience is a 'selfish' trait serving the interests of individuals; it is set aside for the 'altruistic' community effort exerted by an individual for the group; and this is manifested in traits such as obedience which may involve cruel and vicious behaviour towards non-group members. Both Milgram' s and Alexander' s interpretation imply that in conditions where a hierarchical form of organisation is required, a switch must take place from 'normal' behaviour which includes a role for the conscience, to the special forms of behaviour, such as obedience, required for group maxirnisation. Milgram was aware that this facility must finally be instantiated in physiological systems such as those of the brain, but realised that the current state of knowledge made such forms of investigation impossible: Where in a human being shall we find the switch that controls the transition from an autonomaus to a systemic mode? No less than in the case of automata, there is certainly an alteration in the internal operations of the person, and these, no doubt, reduce to shifts in patterns of neural functioning. Chemical inhibitors and disinhibitors alter the probability of certain neural pathways and sequences being used. But it is totally beyond our technical skill to specify this event at the chemoneurological levei. 119

Milgram's approach was that adopted by evolutionary psychologists: to focus on the Darwinian algorithrns responsible for the switching as a sufficient explanation of the mechanisms underlying the functional display of obedience: However there is a phenomenological expression of this shift to which we do have access. The critical shift in functioning is reflected in an alteration of attitude. Specifically, the person entering an authority system no Ionger views hirnself as acting out of bis own purposes but rather comes to see hirnself as an agent for executing the wishes of another person. Once an individual conceives bis action in this light, profound alterations occur in bis behavior and bis internal functioning. These are so pronounced that one may say that this altered attitude places the individual in a different state from the one he was in prior to the integration into the hierarchy. I shall call this the agentic state, by which I mean the condition a person is in when he seeshirnself as an agent for carrying out another person's wishes. This

Hard Times, ed. by Artbur L. Caplan and Daniel Callahan, Ethics 94(1) (October 1983): 138-140, p. 140. 119

u•

Milgram, Obedience to Authority, p. 133.

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term will be used in Opposition to that of autonomy hirnself as acting on his own. 120

that is, when a person sees

Milgram recognised that this Darwinian algorithm is a psychological mechanism, of a different category from the functional behaviour that it is instrumental in producing: ls the agentic state just another word for obedience? No, it is that state of mental organization which enhances the likelihood of obedience. Obedience is the behavioral aspect of the state. A person may be in an agentic state - that is, in a state of openness to regulation from an authority - without ever being given a command and thus never having to obey. 121

Having identified this switch from autonomaus behaviour to the agentic state as the critical area of study, Milgram analysed the surrounding conditions and consequences of this shift. This discussion is too complex to be adequately reviewed here, but it includes consideration of the developmental process and environmental effects as "antecedent conditions", the psychological and behavioural properties of the agentic state itself, and the influences which prevent individuals from leaving it, the "binding factors". 122 These are brought together in explaining particular results of the experiments: the intense strain felt by many participants, and the disobedience which some subjects demonstrate. 123 Finally Mi! gram compared his explanation and the results of the experiments with the principal competing hypothesis: that the subject's behaviour should be interpreted as aggressive tendencies released in the permissive laboratory context. The experimental variation in which the naive subjects were entirely free to choose from the available shock Ievels most directly falsifies this hypothesis: One or two, at most, seemed to derive any satisfaction frorn shocking the learner. The Ievels were in no way cornparable to that obtained when the subjects are ordered to shock the victirn. There was an order-of-rnagnitude difference. 124

120

Ibid., [ernphasis in the original].

121

lbid., p. 148.

122

lbid., pp. 135-152.

123

lbid., pp. 153 ff.

124

lbid., p. 167.

4. Aggregate Maximisation and Non-Optimality

165

Further evidence was provided by the tension and conflict apparent in the subjects, and their responses to the different role permutations such as their refusal to shock the experimenter against bis will. Milgram's explanation of the obedience results thus constitutes an elegant application of the methodology of evolutionary psychology, with phylogeny, function, mechanism, and ontogeny and situation, together being used to provide a convincing explanation of an apparently anomalous phenomenon. 4. Aggregate Maximisation and Non-Optimality

The preceding sections have analysed in turn the general characteristics of maximisation for the genet, kin-group, and group Ievels, and have reviewed psychological and behavioural research supporting hypotheses derived from these general specifications. Although this tripartite division is very useful for analytical purposes, the genetic replicators for which the vehicles exist are unitary entities, as are the individuals they create through ontogenetic processes. The fundamental principle is that the entire lifetimes of individuals and all the behavioural, cognitive, morphological and physiological mechanisms associated with them, have been shaped by natural selection in ways that maximised the survival of the genetic replicators through each of the vehicles in the environment of evolutionary adaptedness. Chapter II discussed the existence of other vehicles than the three considered above, in particular species and coreplicons. Given appropriate theoretical and empirical developments, 125 it may be possible to specify maximisation equations for these vehicles and investigate the supporting cognitive processes. This work is restricted to the genet, kin-group, and group vehicles, however, so that the aggregate contribution of all forms of effort (AE) to the survival of genetic replicators for a specific trait in the environment of evolutionary adaptdness is given by the sum of the net fitness contributions through somatic, reproductive and community effort (SE, RE, CE): [5.13]

125 For approaches to the implications for degrees of relationship caused by coreplicons see e.g., Cosmides and Tooby, 'Cytoplasmic Inheritance' , p. 122; Hamilton, 'Extraordinary Sex Ratios', pp. 480-481.

166

V. From Psychology to Behaviour

Thus, for example, if community effort such as obedient behaviour emerged through group selection in the EEA, then it can be assumed that in aggregate the adaptation made a positive contribution to the survival of genetic replicators (AWAE) through the group vehicle (AWcE), even though the selection pressure on the genet and the kin-group may have been in the opposite directions. The specifications derived in the earlier sections for the three vehicles results from the maximisation of benefit less cost, i.e., the difference between the benefit to the vehicle concerned and the cost to the focal organism as mechanism. The common form of the 'supply' of traits by the organism allows all of the specific costs to be summed to form the individual's aggregate effort. In contrast, the functional 'demands' by the various vehicles are measured in different dimensions appropriate to each vehicle, and the benefit terms must therefore be separately substituted into equation 5.13, giving:

[5.14]

max

n

!:J. WAE = B;

+

i

L

(r1 i B)

"'

L

+

(Flk Bk) - C1

k = 1

= 1

In the absence of other vehicles, equation 5.14 can be assumed to represent the general ex post result of selection at the various Ievels in the EEA. 1t should be clear that the actual characteristics of an adaptation will be result of the degree of conflict between the 'purposes' of the three vehicles, and the strength of selection at each of these Ievels. Following the general pattern, the a priori expression is: [5.15] max !:J. WE(AEJ = E(B;)

L n

+

i

= 1

L "'

e (r 1i)E(Bi)

+

k = 1

e (F1 k)E (Bk)- E( C1)

The expression in the new space for traits expressed in the present is: [5.16] max

1TE(A.EJ

= E(B;) +

n

L

i •

e(r1i)E(B) 1

"'

+

L

k

=1

e(F1 k)E(B*)-E(C1)

Finally, the expectation terms may be specified in the form of their discounted streams over time, giving the net aggregate value (NA V) of a particular form of behaviour as a result of its impact on each of the three vehicles as:

4. Aggregate Maximisation and Non-Optimality

NA V "'

1t ECAE)

= E(B;)

n

+

gr_c; ,)

[5.17]

L

e (r; i) E(Bi)

j • I

(1

+

167

m

+

L

r. (F; k) E(Bk)

k • I

gr_c; z) d; ,)(1 + d; 2) gr_ci E(D))

where E(B.)"' 1

gr_s; ,>

1

+

d;

gr_s; 2>

+ I

(1

+

di 1)(1

+

d; 2)

+

It is a principal conclusion of this work that equation 5.17 represents the general specification of 'purpose' for the hierarchy of traits, from behaviour through to physiology and biochemistry, which humans and other organisms exhibit. Should this be correct, then all systematically manifested traits can be interpreted in terms of the maximisation of the net aggregate value NA V, albeil in a space which may not be discernible to an extemal observer, and which is unlikely to result in the maximum possible contribution to the survival of the relevant genetic replicators. This derivation of an aggregate maximisation function allows the formulation of maximising models with respect to behaviour, a principal theme of the following chapter.

VI. Homo Biologicus and Human Characteristics 1. Characterising Homo Biologicus

The preceding chapter has derived the expressions for the maximisation that takes place for the principal vehicles, and has provided examples of types of behaviour that may be interpreted in this way. The approach taken was that of evolutionary psychology, where general pattems of behaviour, such as habitat selection or rape, are interpreted in terms of the underlying cognitive mechanisms. Examination of figure 3.1 (pages 42, 43) indicates, however, why evolutionary psychology alone is incapable of creating predictive models of behaviour. Evolutionary psychology identifies the species-typical psychological adaptations at the cognitive Ievel, but far more information is needed before it can be predicted whether, for example, the illustrative bird will sing a speciestypical mating song on a particular spring morning. Genetic variability, ontogenetic development, and situational influences mean that every organism has a unique genetic constitution and life history, and faces a different environment. Evolutionary psychology may account ex post for the cognitive mechanisms which enabled the bird to sing, but is incapable of predicting behaviour ex ante. Fortunately for human freedom it is impossible to create complete models of individual behaviour, a theme retumed to in the final subsection of this chapter. This is, however, a familiar problem: physicists do not attempt to predict the behaviour of each particle, chemists each molecule, biologists each organism, or economists each consumer. What each of these disciplines have achieved, and this is one of the characteristics which makes them sciences, is so to simplify the complex world they observe that general laws can be specified which provide a framework within which particular phenomena can be understood and predicted. 1

1

See e.g., Friedman, 'Methodology of Positive Economics', pp. 33-34.

1. Characterising Homo Biologicus

169

As a result of this generalising character of science the goal of a general science of behaviour is not to account for and predkt each person' s actions, but rather the actions of a typical individual. 2 The concentration on the representative, rather than the specific, allows the treatment of individual diversity resulting from genetic variability and ontogenetic development as statistically distributed variations around the mean. The model is then specified in terms of the relationship between the representative individual's cognitive structures and his or her behaviour in particular situations. This methodology is well developed in neoclassical economics,3 where underlying tastes and preferences are assumed to be represented by a utility function. The approach then analyses the behaviour of representative individuals in terms of "the logic of the situation" ,4 normally through the concept of markets. The general principle is that the surrounding environment so constrains the available options that representative individuals have only a "single exit".5 This conception of progressing from individual psychologies

2 This principle was used in the derivation of the maximisation conditions in the previous chapter, by respecifying the ex post equation in terms of the expected costs and benefits for typical individuals with respect to the problern at hand (i). I interprete these conceptual entities as being typical individuals with respect to the problern at hand, which are useful for the modeHing of individual behaviour, but which cannot be simply used to model group behaviour. For the dangers of creating models of aggregate behaviour based directly on representative individuals, see Alan P. Kirrnan, 'Whom or What does the Representative Individual Represent?' Journal of Economic Perspectives 6(2) (1992): 117-136. 3 Neoclassical economics is primarily concemed with the analysis of the behaviour of maximising actors in product and other markets, in partiewar the equilibria that may be the aggregate result of their individual decisions. For presentations with links to the themes developed in this book see e.g., Robert H. Frank, Microeconomics and Behavior (New York: McGraw-Hill, 1991), Hirshleifer, Price Theory; George J. Stigler, The Theory of Price, [1942] 4th ed. (New York: Macmillan, 1988); Becker, Economic Approach, esp. pp. 3-14. Foramore abstract presentation see e.g., Kenneth J. Arrow and Frank H. Hahn, General Competitive Analysis (Amsterdam: North-Holland, 1971). 4 Karl R. Popper, The Poverry of Historicism (London: Routledge & Kegan Paul, 1957), p. 149.

Richard N. Langlois, 'Rationality, Institutions, and Explanation' in Richard N. Langlois (ed.), Economics as a Process: Essays in the New /nstitutional Economics, pp. 225-255 (Cambridge: Cambridge University Press, 1986), p. 230 [hereafter Langlois, 'Rationality, Institutions, and Explanation']. An early articulation was von Mises's answer to critics who asserted that the "basic notion of economics, viz., the choosing and acting individual, is . . . an unrealistic concept" by asserting that, in fact, "Man is 5

170

VI. Homo Biologicus and Human Characteristics

which are imperfectly known and which vary among actors, to the aggregate behaviour of similar groups of individuals, is widely known as situational determinism: Situational determinism assumes that the decision maker knows his situation better than he is assumed to know it in the conditions usually investigated in decision theory. It is part and parcel of the neoclassical prograrnme to specify situations which uniquely determine behaviour. Calculation of the uniquely appropriate behaviour is reduced to elementary logic and elementary common sense. W e concentrate on the logic of the agent's situation and are spared the complexities of the psychology of the agent in the situation. The motivational and evaluational characteristics of the acting agent become largely omamenta1.6

Representative individuals in economics are generally given names such as "Homo oeconomicus", "rational actors", or "maximising agents", and are normally assumed to display certain psychological properties. Homo biologicus is the name given here to an equivalent model, whose cognitive characteristics are based on the findings of evolutionary psychology. The limitations of my knowledge - and this work - mean that the analyses of behaviour based on this evolutionary model of man are initial suggestions rather than well-specified hypotheses. Homo biologicus is in effect a "candidate" model of man, resulting from a concern with the "discovery" and exposition of an evolutionary approach to the human sciences, rather than the verification of particular hypotheses. 7

unconditionally subject to the natural conditions of his environment. In acting he must adjust hirnself to the inexorable regularity of natural phenomena. It is precisely the scarcity of the nature-given conditions of his welfare that enjoins upon man the necessity to act". (Ludwig von Mises, Human Action: A Treatise on Economics (New Haven, CT: Yale University Press, 1949), p. 643-644). 6 Spiro J. Latsis, 'Situational Determinism in Economics' British Journal for the Philosophy of Science 23 (1972): 207-45 [emphasis in the original]. See also Langlois, 'Rationality, Institutions, and Explanation', pp. 230-238; Fritz Machlup, 'Situational Determinism in Economics' British Journal for the Philosophy of Science 25 (1974): 271-284; Spiro J. Latsis, 'The Limitations of Single Exit Models: Reply to Machlup' British Journal for the Philosophy of Science 27 (1976): 51-60; Spiro J. Latsis, 'A Research Program in Economics' in Spiro J. Latsis (ed.), Method and Appraisal in Economics, pp. 1-41 (Cambridge: Cambridge University Press, 1976).

7 "Scientists are faced with a set of phenomena and no theory that explains them in a minimally acceptable way. In this more typical situation, the scientific task is not to verify or falsify theories, to choose between alternative theories, but to discover candidate theories that might help to explain the facts" (Herbert A. Simon, Models of Discovery and Other Topics in the Methods of Science Boston Studies in the Philosophy

I. Characterising Homo Biologicus

171

A central characteristic of Homo oeconomicus is the assumption of rational maximisation: It is only a short step from these examples to the economic hypothesis that under a wide range of circumstances individual frrms behave as if they were seeking rationally to maxirnize their expected retums (generally if rnisleadingly called profits) ... and had full knowledge of the data needed to succeed in this attempt; as iJ, that is, they knew the relevant cost and demand functions, calculated marginal cost and marginal revenue from all actions open to them, and pushed each line of action to the point at which the relevant marginal cost and marginal revenue were equal. Now, of course, businessmen do not actually and literally solve the system of simultaneous equations in terms of which the mathematical economist finds it convenient to express this hypothesis, any more than leaves or billiard players explicitly go through complicated mathematical calculations or falling bodies decide to create a vacuum. 8

This "as if' assumption has been the subject of considerable criticism and a substantialliterature,9 but the prevailing consensus among practising economists appears to have been that it is justified because the results achieved through using it are preferable to comparable approaches. In the light of the preceding discussion it is possible to see why this model has indeed provided "predictions that are the good enough for the purpose at band [and) better than predictions from alternative theories. "10 Evolutionary processes have endowed individuals with psychological

of Science, Vol. 54, Synthese Library Vol. 114 (New York: Macmillian, 1977), pp. xvi-xvii [emphasis in the original)). The contrast between discovery and verification clearly parallels Kuhn's distinction between "normal science" and "paradigm change" (Thomas S. Kuhn, The Structure of Scientific Revolutions, [1962] 2nd enlarged ed. (Chicago: Chicago University Press, 1970), passim [hereafter Kuhn, Scientific Revolutions]), but is preferable for cases such as this where no clear paradigm is being overthrown. See also Kar1 R. Popper, Conjectures and Refutations: The Growth of Scientific Knowledge, 3rd ed. (London: Routledge & Kegan Paul, 1969). 8 Friedman, 'Methodology of Positive Econornics', pp. 21-22 [emphasis in the original]. This is generalised later: "It is frequently convenient to present [such] a hypothesis by stating that the phenomena it is desired to predict behave in the world of observation as if they occurred in a hypothetical and highly simplified world containing only the forces that the hypothesis asserts tobe important" (ibid., p. 40 [emphasis in the original]). 9 For a review of and response to - such criticisms, see Lawrence R. Boland, 'A Critique of Friedman's Critics' Journal of Economic Literature 17(2) (June 1979): 503-522.

°Friedman, 'Methodology of Positive Economics', p. 41.

1

172

VI. Homo Biologicus and Human Characteristics

characteristics that pennitted maximisation of replicator survival in the environment of evolutionary adaptedness, and it is these old cognitive programs operating in new spaces that underpin the maximising assumption of the economic approach. Although economists sometimes attribute maximisation to supra-individual entities, the vast majority of economic research is predicated upon the assumption of selfish individual maximisation, very often with the goal of satisfying "material needs and desires". 11 It should be apparent from the preceding discussion that it is the maximisation of somatic resources - such as wealth and status - which underlies this assumption. 12 An economic framework based on the unebanging nature of somatic resources is the model of consumer choice developed by Becker and his colleagues: In broad outline, this approach views as the primary objects of consumer choice various entities, called commodities, from which utility is directly obtained. These cornrnodities are produced by the consumer unit itself through the produclive activity of combining purchased market goods and services with some of the hausehold' s own time. In this frarnework all market goods are inputs used in production processes of

11 Albert Rees, 'Economics', p. 4 72. This is the traditional conception of economics, as illustrated by Marshall's statement that "economics is a study of mankind in the ordinary business of life; it examines that part of individual and social action which is most closely connected with the material requisites of well-being" (Alfred Marshall, Principles of Economics: An Introductory Volume, 8th ed. (London: Macrnillan, 1956), p. 1). See also Lionel C. Robbins, An Essay on the Nature and Significance of Economic Science, [1932]2nd ed. rev. and extended (London: Macmillan, 1935), pp. 123; Becker, Economic Approach, pp. 3-4. 12 The systematic use of this assumption extends back to Smith e.g., "lt is not from the benevolence of the butcher, the brewer, or the baker, that we expect our dinner, but from their regard to their own interest. We address ourselves, not to their humanity but to their self-love, and never talk to them of our own necessities but of their advantages" Adam Smith, An lnquiry into the Nature and Causes of the Wealth of Nations, 2 vols., [1776] facsimile of the 1976 Oxford University Press edition, ed. by R.H. Campbell, A.S. Skinner, and W.B. Todd (lndianapolis, IN: Liberty Classics, 1981), pp. 26-27. For Srnith's views in general see Ronald H. Coase, 'Adam Srnith's View of Man' Journal of Law and Economics 19(3) (October 1976): 529-546, and for histories of the development of the concept of self interest see e.g., Albert 0. Hirschrnan, The Passions and the Interests: Political Arguments for Capitalism before lts Triumph (Princeton, NJ: Princeton University Press, 1977); Stephen Holmes, 'The Secret History of Self-Interest' in Jane J. Mansbridge (ed.), Beyond Self-Interest, pp. 267-286 (Chicago, IL: University of Chicago Press, 1990).

1. Characterising Homo Biologicus

173

the nonmarket sector. The consumer's demand for these market goods is a derived demand analogaus to the derived demand by a firm for any factor of production. 13

This assumption, that the vagaries of observed behaviour result from the demand for these fundamental somatic resources, allows a graceful transition to be made between the varied, complex, and changing character of "material needs and desires" - as expressed for example in cars of a certain style or dresses of a certain length - and the generality of the objectives lying behind such behaviour: The establishment of the proposition that one may usefully treat tastes as stable over time and sirnilar among people is the central task of this essay. The ambitiousness of our agenda deserves emphasis: we are proposing the hypothesis that widespread and/or persistent human behavior can be explained by a general calculus of utility-maxirnizing behavior, without introducing the qualification "tastes remaining the same." 14

These sirnilarities between analyses based on Homo oeconornicus and those potentially using Homo biologicus should not obscure the fact, however, that important differences exist between the two approaches, centring upon the concepts of maxirnisation, individuality, and rationality.

13 Robert T. Michael and Gary S. Becker, 'On the New Theory of Consumer Behavior' Swedish Journal of Economics 75(4) (December 1973): 378-396 at p. 381 [hereafter Michael and Becker, 'New Theory']. This is a major break with traditional theory, where consumer utility functions are normally simply defined over goods and services that can be purchased; see e.g., George J. Stigler and Gary S. Becker, 'De Gustibus Non Est Disputandum' American Economic Review 67(2) (March 1977): 76-90 at p. 76 [hereafter Stigler and Becker, 'De Gustibus']. See also Gary S. Becker, 'A Theory of the Allocation of Time' Economic Journal 75(299) (September 1965): 493-517 {reprinted in Gary S. Becker The Economic Approach to Human Behavior (Chicago: University of Chicago Press, 1976), pp. 89-114}, esp. pp. 495-500 {pp. 91-96} [hereafter Becker, 'Allocation of Time']; Kelvin J. Lancaster, 'A New Approach to Consumer Theory' Journal of Political Economy 74 (1966): 132-157. 14 Stigler and Becker, 'De Gustibus', p. 76. For criticisms of this approach independent of the alleged deterrninism considered below, see e.g., Albert 0 . Hirschman, 'Against Parsimony: Three Easy Ways of Complicating Same Strategies of Econornic Discourse' American Economic Review: Papersand Proceedings 74 (1984): 89-96, p. 90;. Edwin G. West and Michael McKee, 'De Gustibus Est Disputandum: The Phenomenon of Merit Wants Revisited' American Economic Review 73 (December 1983): 1110-1121 ; Tyler Cowen, 'Are All Tastes Constant and ldentical? A Critique of Stigler and Becker' Journal of Economic Behavior and Organization 11(1) (January 1989): 127-135.

174

VI. Homo Biologicus and Human Characteristics

Maximisation. Perhaps the most profound difference isthat the maximisation conditions derived in the previous chapter applied to traits that were shaped in the environment of evolutionary adaptedness, and result in maximisation by representative humans in spaces which are unlikely to be associated with the maximisation of replicator survival in the present. This implies that models based on Homo biologicus can not be specitied "as if' maximisation takes place, as utility maximising by individuals or profit maximising by firms is assumed in economic models. Maximisation by Homo biologicus, as with all of its cognitive processes, is domain specific: that involved in choosing an optimal habitat is qualitatitively different from those for the assessment of risk or the determination of sexual strategies, for example. Those human sciences which focus on behaviour must thus cooperate with others that identify behaviour' s underlying mechanisms, in order to determine the specific features of presentday maximisation and hence create accurate models of behaviour. lndividuality. The second major difference is that Homo oeconomicus has a simple and constant psychology: within a particular model it is generally assumed to egoistically maximise its own utility, or to represent the united interests of a supra-individualistic entity such as a household, a state, or a firm.15 While theoretically predicated on methodological individualism, 16 the ascription of maximising behaviour to such multi-individual units has created

15 Sen concludes that in standard economic theory "the nature of individual objectives is typically characterized in an extraordinarily simple form" (Amartya K. Sen, 'Prediction and Economic Theory' Proceedings ofthe Royal Society of London: Maths & Physics Series 407(1832) (1986): 3-23 at p. 7 [hereafter Sen, 'Prediction and Economic Theory']), and identifies the three assumptions involved as self-centred welfare, self-welfare goal, and self-goal choice (ibid.). See also Amartya K. Sen, 'Rational Fools: A Critique of the Behavioral Foundations of Economic Theory' Philosophy and Public Affairs 6 (Summer 1977): 317-344 {reprinted in Amartya K. Sen Choice, Welfare and Measurement, (Oxford: Basil Blackwell, 1982), pp. 84-106} esp. pp. {89} ff. [hereafter Sen, 'Rational Fools']; Amartya K. Sen, 'Rationality and Uncertainty' Theory and Decision 18 (1985): 109-127. 16 See e.g., Geoff Hodgson, 'Behind Methodo1ogical Individualism' Cambridge Journal of Economics 10(3) (September 1986): 211-224, esp. pp. 212-217; Timothy W. Luke, 'Methodological Individualism: The Essential Ellipsis of Rational Choice Theory' Philosophy of the Social Seiences • Philosophie des Seiences Sociales 17(3) (1987): 341-355; Randall G. Holcombe, Economic Modelsand Methodology, Contributions in Economics and Economic History, No. 99 (Westport, CT: Greenwood Press, 1989), esp. pp. 71-86; Roben Nozick, 'On Austrian Methodology' Synthese 36(3) (November 1977): 353-392, esp. pp. 353-361.

1. Characterising Homo B iologicus

175

methodological difficulties which are discussed below with respect to family altruism and war. Homo biologicus, in contrast, has a complex and variable psychology, involving a fundamental difference between the entity which the behaviour was designed 'for' (the vehicles, and ultimately the replicators, in the environment of evolutionary adaptedness), and the entity which exhibits the behaviour (the focal individual). In addition, the domain-specificity of cognitive processes implies that individuals will switch from one domain to another: from 'rational' decisions about purchases to 'emotional' decisions about sex or aggression, for example. Homo biologicus is thus compatible with methodological individualism because behaviour is exhibited by individuals, but generates supra-individualistic entities through behaviour which was selected for the kin-unit and group vehicles in the evolutionary past. Rationality. The third difference is that many economists have concentrated on rationality as a feature of Homo oeconomicus, illustrated by the use of such expressions as "rational actor". Although not inherently necessary to the economic approach through the possibility of using the "as if' assumption, rationality is often assumed to be a defining criteria for economic analysis, 17 so that "a non-rational domain implies some indeterminacy in behavior; it places all further discussion outside the scope of science" .18 The concept of rationality plays in contrast no role in Homo biologicus, tending, with terms like "culture" or "values", to confuse rather than clarify the problems at hand.19

In order to make clearer how an approach based on Homo biologicus differs from conventional economics, the following sections discuss four types of behaviour: choice under uncertainty, securities markets, farnily altruism, and war. Although, as noted, no attempt has been made to provide testable alternative hypotheses, the general characteristics of models based on Homo biologicus should become apparent through these specific examples.

17 "The assumption of rational behavior, especially rational utility maximisation, lies at the very heart of neoclassical economic theory. Virtually every mainstream article and book, especially in the area of rnicroeconomics, relies on this assumption." Ken McCorrnick, 'An Essay on the Assumption of Rational Behavior in Economics' Review of Social Economy 47(3) (Fall 1989): 313-321 at p. 313.

18 Richard B. McKenzie, 'The Non-Rational Domain and the Limits of Economic Analysis' Southem Economic Jouma/46(1) (July 1979): 145-157). 19 As Sen notes, "sometimes the notion of rationality is completely identified with maximization. However, maxirnizing behaviour need not be confined only to the pursuit of self-interest" Sen, 'Prediction and Econornic Theory' , p. 8.

176

VI. Homo Biologicus and Human Characteristics

In terms of their subject matter these themes range from experimental psychology, to economics, to soeiology, to international relations. All the models examined are inherently economic in character, however, as they are all predicated on the existence of maximising actors. Economics is only one of the human sciences concerned with behaviour, and it may appear that a more produclive approach to the characterisation of Homo biologicus would have been to examine interpretive frameworks from other soeial seiences such as sociology, social psychology, criminology, or political science. The basis for the concentration on economics is that economists have conseiously attempted to employ the methods of the natural sciences in the task of explaining human behaviour. In particular they are generally committed to methodological individualism, which is why such importance attaches to Homo oeconomicus and its characteristics.20 The other soeial seiences have often seen human characteristics and behaviour as existing in a different realm, and have criticised attempts at creating seientific explanations as reductionistic. Instead of forming hypotheses in terms of the behaviour of individuals, explanations have often been developed in terms of abstract entities, such as groups or classes, or abstract concepts, such as values or culture. 21

20 Other domains offer the possiblity of comparing explanations based on each of the models of human characteristics; Homo oeconomicus, Homo biologicus, and those (Homo sociologicus) that do not fall into these categories. One example is suicide, where economic and evolutionary psychological approaches exist (see e.g., D. Lester, 'Rational Choice Theory and Suicide' Activitas Nervosa Superior 30(4) ( 1988): 309-312; Denys de Catanzaro, 'Human Suicide: A Biological Perspective' Behavioral and Brain Seiences 3(2) (June 1980): 265-290; Denys de Catanzaro, 'Suicidal Ideation and the Residual Capacity to Promote lnclusive Fitness: A Survey' Suicide and Life-Threatening Behavior 14(2) (Summer 1984): 75-87; Denys de Catanzaro, 'A Mathematical Model of Evo1utionary Pressures Regulating Self-Preservation and Self-Destruction' in Ronald W. Maris (ed.), Biology of Suicide, pp. 84-99 (New York: Guilford Press, 1986); Denys de Catanzaro, 'Evolutionary Limits to Self-Preservation' Ethology and Sociobiology 12( 1/2) ( 1991 ): 1-11 ). These can be compared to more eclectic approaches, which draw for example on sociology and psychiatry; see e.g., Ronald W. Maris, Pathways to Suicide: A Survey ofSelf-Destructive Behaviors (Baltimore, MD: Johns Hopkins University Press, 1981), David K. Reyno1ds and Norman L. Farberow, The Family Shadow: Sources of Suicide and Schizophrenia (Berkeley, CA: University of California Press, 1981). Unfortunately each of the mode1s tends to share some aspects with the others, and the availab1e data is limited, so that it is very difficult to differentiale between and falsify the hypotheses. 21 Evolutionary psychologists have shown the inadequacy of a purely cultural orientation in the social sciences and the superiority of an evolutionary approach; see

1. Characterising Homo Biologicus

177

This abstract orientation has left the individual characteristics that have been assumed relatively vague, so that, for example, the characteristics of Homo sociologicus are primarily defined in terms of its reaction to group influences, rather than the group being defined in terms of Homo sociologicus. Such interpersonal influences are clearly of enormous importance in the characterisation of Homo biologicus - conformity and obedience are strongly group-context related for example - but such supra-individualistic phenomena are most appropriately analysed as the consequence of certain individual characteristics, rather than as subjects of investigation in their own right. Even though the intrinsic realism of such supra-individualistic explanations may be greater than that of competing economic hypotheses/2 the deficiency of a

esp. John Tooby and Leda Cosmides, 'The Psychological Foundations of Culture' in Jerome H. Barkow, Leda Cosmides, and John Tooby (eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, pp. 19-136 (Oxford: Oxford University Press, 1992) [hereafter Tooby and Cosmides, 'Foundations of Culture']. See also Symons, 'Darwinian Anthropology'; Tooby and Cosmides, 'Evolutionary Psychology and Culture, I'. In criticising such group-based approaches Tooby and Cosmides have, however, ignored the multiplicity of different approaches to be found within the social sciences. In a recent long essay they argue that "There is a set of assumptions and inferences about humans, their minds, and their collective interaction - the Standard Social Science Model - that has provided the conceptual foundations of the social sciences for nearly a century and has served as the intellectual warrant for the isolationism of the social sciences" (Tooby and Cosmides, 'Foundations of Culture', p. 23). This allegedly general model starts with common facts and then focuses on individual development in response to the local society (ibid. p. 25). Unfortunately in concentrating upon this particular school Tooby and Cosmides have inherited its objective - the explanation of culture - rather than tackling the more prosaic task of explaining behaviour: "Advances in recent decades in a number of different disciplines, ... have made clear for the frrst time the nature of the phenomena studied by social scientists and the connections of those phenomena to the principles and fmdings in the rest of science. This allows a new model to be constructed - the Integrated Causal Model - to replace the Standard Social Science Model" (ibid. p. 25). Although their approach may be appropriate for understanding the cultural differences between societies, it is does not even attempt to address the particular forms of behaviour studied by the majority of social scientists, Iet alone succeed in constructing an adequate alternative model. 22 Smelser's explanation of panic and riots is, for example, more convincing than alternatives based on Homo oeconomicus; see e.g., Neil J. Smelser, Essays in Sociological Explanation (Englewood Cliffs, NJ: Prentice Hall, 1968), esp. pp. 108-115 [hereafter Smelser, Sociological Explanation]. Cf. J. Patrick Gunning, 'An Economic Approach to Riot Analysis' Public Choice 13 (Fall 1972): 31-46; Richard B. McKenzie

12 Elworthy

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VI. Homo Biologicus and Human Characteristics

supra-individualistic methodology23 is one of the factors underpinning "econornic imperialism" in the social sciences. 24

and Gordon Tullock, The New World of Economics: Explorations into the Human Experience, 2nd ed (Homewood, IL: Richard D. lrwin, 1978), pp. 253-261. A similar conclusion applies to the competing explanations of Scott and Popkin concerning the behaviour of Asian peasants. See James C. Scott, The Moral Economy of the Peasant: Rebellion and Subsistence in Southeast Asia (New Haven, CT: Yale University Press, 1976); James C. Scott, 'Everyday Forms of Peasant Resistance' Journal of Peasant Studies 13(2) (January 1986): 5-35; James C. Scott, Weapons of the Weak: Everyday Fonns of Peasant Resistance (New Haven, CT: Yale University Press, 1986); Samuel L. Popkin, The Rational Peasant: The Political Economy of Rural Society in Vietnam (Berkeley, CA: University of Califomia Press, 1979). 23 Sociologists such as Smelser realise the danger of regarding "the individual person as a kind of passive vessel through which the social forces work" (Smelser, Sociological Explanation, p. 106). Tilly has identified four problems with sociological analyses of group behaviour such as collective action: "(1) Gaps within the available models ... (2) Use of single-actor models ... (3) Use of static models ... (4) Use of causal rather than purposive models of behaviour" (Charles Tilly, 'Models and Realities of Popular Collective Action' Social Research 52(4) (Winter 1985): 717-747, pp. 717-718 [original in italics]. He comments that "in general a theorist achieves a solution to one of the problems by exaggerating another one - constructs a purposive account of collective action, for instance, by postulating single actors having unitary dispositions" (ibid., p. 718). A methodology is suggested below which may be capable of overcoming the problern that "theorists Iack the means to create dynamic multiactor causal models of such complex phenomena" (ibid., p. 718). 24 Seegenerally Gerard Radnitzky and Peter Bemholz, (eds.), Economic lmperialism: The Economic Approach Applied Outside the Field of Economics (New York: Paragon House, 1987); Jack Hirshleifer, 'The Expanding Domain of Econornics' American Economic Review 75(6) (1985): 53-68; Bruno S. Frey, Ökonomie ist Sozialwissenschaft: Die Anwendung der Ökonomie auf neue Gebiete (München: Pranz Vahlen, 1990); George J. Stigler, 'Economics: The Imperial Science?' Scandinavian Journal of Economics 86(3) (1984): 301-303; Gordon Tullock, 'Economic Imperialism' in James M. Buchanan and R. Tollison (eds.), The Theory of Public Choice, pp. 317-329 (Ann Arbor, MI: University of Michigan Press, 1972); Peter Weise, 'Homo Oeconornicus und Homo Sociologicus: Die Schreckensmänner der Sozialwissenschaften' Zeitschrift für Soziologie 18(2) (April 1989): 148-161; James S. Coleman, Individual lnterests and Collective Action: Selected Essays (Cambridge: Cambridge University Press, 1986); James S. Coleman, Foundations of Social Theory (Cambridge, MA: Harvard University Press, 1990); Karl-Dieter Opp, 'Das Modell des Homo Sociologicus: Eine Explikation und eine Konfrontierung mit dem utilitaristischen Verhaltensmodell' Analyse und Kritik: Zeitschrift für Sozialwissenschaften 1 ( 1988): 1-27.

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The specification of Homo biologicus is explicitly reductionistic, while allowing for such interpersonal influences, and hence a common methodological foundation is shared with economics. This mirrors the mutually fertile relationship that has existed between economics and biology which extends back to Malthus's influence on Darwin/5 and which anticipates some aspects of the Homo biologicus approach. The earliest and perhaps most accurate of these is the depiction of a complex system by Edgeworth, where a weak electromagnetic force, in attempting to reach a maximum, exerts power in the world by governing a steam engine acting with a !arge number of degrees of freedom. 26 Edgeworth creates an analogy with human characteristics, where cognitive processes which were shaped by evolutionary forces (such as those which generate pleasure), act as mechanisms for behaviour: Similarly pleasure in the course of evolution has become throned among grosser subject energies - as it were explosive engines, ready to go off at the pressure of a hair-spring. Swayed by the frrst principle, she sways the subject energies so as to satisfy her own yearning towards maximum; 'her every air Of gesture and least motion' a law of Force to governed systems- a fluent form, a Fairy Queen guiding a most complicated chariot, wheel within wheel, the 'speculative and active instrurnents,' the motor nerves, the lirnbs and the environment on which they act. A system of such charioteers and chariots is what constitutes the object of Social Science. The attractions between the charioteer forces, the collisions and compacts between the chariots, present an appearance of quantitative regularity in the midst of bewildering complexity resernbling in its general characters the field of electricity and magnetism. To construct a scientific hypothesis seems rather to surpass the powers of the writer than of Mathematics?7

With bis identification of the roles of evolution; maximisation; psychological, morphological and physiological mechanisms; the function of behaviour; and

2s See Darwin, Origin of Species, esp. pp. 5, 63. See also Ghiselin, Triumph of Darwinian Method, esp. pp. 48-77; Grober, Darwin on Man; Ernst Mayr, The Growth of Biological Thought: Diversity, Evolution, and lnheritance (Cambridge, MA: Belknap Press, 1982), esp. pp. 478-479; Howard Margolis, Patterns, Thinking, and Cognition: A Theory of Judgement (Chicago: Chicago University Press, 1990), esp. pp. 194-195 [hereafter Margolis, Patterns, Thinking, and Cognition].

26 "The delicate electro-rnagnetic force is placed in such a comrnanding position that she sways the rnovernents of the steam engine so as to satisfy her own yeaming towards maximum" F.Y. Edgeworth, Mathematical Psychics: An Essay on the Application of Mathematics to the Moral Seiences (London: C. Kegan Paul, 1881), p. 14. 27

12•

Ibid. [emphasis in the original].

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psychological and behavioural interactions, Edgeworth has sketched the essential elements of the Homo biologicus approach. 28 More recent writers have, for example, interpreted the economic concepts of preference and utility from an evolutionary perspective,29 or applied concepts from one discipline to problems

28 In his poetical reference to the guidance of the "most complicated chariot" with wheels within wheels and the lower Ievel mechanisms, the "speculative and active instruments" such as motor nerves and limbs, Edgeworth has clearly perceived the existence of the hierarchy of function and mechanism existing to serve his "Fairy Queen". Edgeworth recognises that cognitive processes (pleasure) do not form the Iimit of this chain - "Swayed by the first principle, she sways the subject energies" - but leaves the nature of the "first principle" unspecified. Given that Mendel's discoveries about particulate inheritance had not been appreciated at the time of writing, Edgeworth could not have extended this perspective to the ultimate "frrst principle": the survival of genetic replicators. 29 In particular Frank has perceived that "the Darwinian model ... provides the only systematic account we have of how tastes actually came into being" (Robert H. Frank, 'The Nature of the Utility Function' in Alan J. MacFadyen and Heather W . MacFadyen (eds.), Economic Psychology: lntersections in Theory and Application, pp. 113-132 (Amsterdam: North-Holland, 1986), p. 130. Unfortunately Frank concentrates on somatic effort, positing that evolutionary theory "is in total harmony with the economist's view that people behave in purposeful, self-serving ways" (ibid.). See also Robert H. Frank, 'If Homo Economicus Could Choose His Own Utility Function, Would He Want One with a Conscience?' American Economic Review 77(4) (September 1987): 593-604; Robert H. Frank, Choosing the Right Pond: Human Behavior and the Quest for Status (Oxford: Oxford University Press, 1985); Robert H. Frank, Passions Within Reason: The Strategie Control of the Emotions (New York: W.W. Norton, 1988); Robert H. Frank, 'A Theory of Moral Sentiments' in Jane J. Mansbridge (ed.), Beyond Self-/nterest, pp. 71-96 (Chicago: University of Chicago Press, 1990); Robert H. Frank, Thomas Gilovich, and Dennis T. Regan, 'Does Studying Economics Inhibit Cooperation?' Journal of Economic Perspectives 7(2) (1993): 159-172. Bruno S. Frey, 'Ein ipsatives Modell menschlichen Verhaltens: Ein Beitrag zur Ökonomie und Psychologie' Analyse und Kritik: Zeitschrift für Sozialwissenschaften 10 (1988): 181-205, esp. p. 186-188; Ulrich Witt, 'Economics, Sociobiology, and Behavioral Psychology on Preferences' Journal of Economic Psychology 12(4) (December 1991): 557-573, esp. p. 563-566; Ulrich Witt, 'Subjectivism in Economics: A Suggested Reorientation' Understanding Economic Behaviour K.G. Grunet and F. Ölander (eds.), ( 1989): 409-431, esp. pp. 416-421; Heinrich W. Ursprung, 'Evolution and the Economic Approach to Human Behavior' Journal of Social and Biological Structures 11(2) (1988): 257-279, esp. pp. 263-267; Stephen E.G. Lea, Roger M. Tarpy, and Paul Webley, The Individual in the Economy: A Textbook of Economic Psychology (Cambridge: Cambridge University Press, 1987), esp. pp. 242-247; Herbert A. Simon, 'Altruism and Economics' American Economic Review: Papersand Proceedings 83(2) (May 1993): 156-161; Eric Aiden Smith and Bruce Winterhalder, 'Natural Selection and Decision

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in the other.30 The limitations of this work mean that it is impossible to adequately review the extent of these links, however, which must remain a theme for future research.

2. Homo Biologjeus versus Homo Oeconomicus

a) Choice under Uncertainty The analysis of choices by individuals under conditions of uncertainty is a central problern in the study of human behaviour. The intimidating mathematical sophistication of much research in this field may give the non-specialist the impression that mathematical models of choice under uncertainty are unaffected by the vagaries of human psychology, resting instead on the objective foundations of pure logic.

Making: Some Fundamental Principles' in Erle Aiden Smith and Bruce Winterhaider (eds.), Evolutionary Ecology and Human Behavior, pp. 25-60, Foundations of Human Behavior Series (Hawthome, NY: Aldine de Gruyter, 1993), esp. pp. 47-50; Yew-Kwang Ng, 'The Paradox of the Adventurous Young and the Cautious 01d: Natural Se1ection vs. Rational Calculation' Journal of Theoretical Biology 153(3) (December 1991): 339-352. See e.g., Robert H. Frank, 'Honesty as an Evolutionarily Stahle Strategy' Behavioral and Brain Seiences 12(4) (December 1990): 705-706; Paul A. Samuelson, 'Complete Genetic Models for Altruism, Kin Selection and Like-Gene Selection' Journal of Social and Biological Structures 6(1) (January 1983): 3-15; Paul A. Samuelson, 'Altruism as a Problem Involving Group versus Individual Selection in Economics and Biology' American Economic Review: Papers and Proceedings 83(2) (May 1993): 143-148; Manfred Tietzel, 'Ökonomie und Soziobiologie oder: Wer kann was von wem lernen?' Zeitschriftfür Wirtschafts- und Sozialwissenschaften 103 (1983): 107-127; Gary S. Becker, 'Altruism, Egoism, and Genetic Fitness: Economics and Sociobiology' Journal of Economic Literature 14(3) (September 1976): 817-826 [hereafter Becker, 'Economics and Sociobiology' ]; Gordon Tullock, 'Biological Extemalities' Journal of Theoretical Biology 33(3) (December 1971): 565-576; Howard Margolis, Selfishness, Altruism and Rationality: A Theory of Social Choice (Cambridge: Cambridge University Press, 1982), esp. pp. 26-35; Robert Boyd and Peter J. Richerson, 'Culture and Cooperation' in Jane J. Mansbridge (ed.), Beyond Self-lnterest, pp. 111-132 (Chicago: University of Chicago Press, 1990); Alan R. Rogers, 'Evolutionary Economics of Human Reproduction' Ethology and Sociobiology 11(6) (November 1990): 479-495. See also Hirshleifer's work, discussed in note 57 page 50. 30

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This has not been the case since the seventeenth century, however, when mathematicians such as Pascal assumed the attractiveness of an uncertain choice to be given by the product of the probability of the events occurring and the value of the outcomes. 31 This is the basis for Pascal's famous wager, that: No matter how small we make the odds of God's existence, the pay-off is infinite; infinite bliss for the saved and infinite misery for the damned. Under such conditions Pascal argued that rational self-interest dictates that we sacrifice our certain but merely finite worldly pleasures to the uncertain but infinite prospect of salvation.32

The general model of classical probability led to the specification of what has become known as the St. Petersburg paradox by Niebolas Bernoulli in 1713: Pierre and Paul play a coin toss game with a fair coin. If the coin comes up heads on the first toss, Pierre agrees to pay Paul $1; if heads does not turn up until the second toss, Paul receives $2; if not until the third toss, $4, and so on. Reckoned according to the standard method, Paul's expectation (and therefore the fair price of playing the game) would be E

= (1/2 X $1) + (1/4 X $2) + (1/8 X $4) + ... + [((1/2)" X $2"- 1)1 + ...

Since there is a small but finite chance that even a fair coin will produce an unbroken run of tails, and since the pay-offs increase in proportion to the decreasing probabilities of such an event, the expectation is infinite. 33

The paradoxical nature of this problern does not derive from the mode of calculation or the infinite answer, both of which are in accord with the conventional mathematics. 1t results rather from the empirical observation that reasonable people would only pay a relatively small sum to participate in such a gamble. The cantrast between the logical answer and observed behaviour provided an impetus to further research, and the 'solution' to this paradox

31 See e.g., Mark J. Machina, 'Choice Under Uncertainty: Problems Solved and Unsolved' Journal ofEconomic Perspectives 1(1) (Summer 1987): 121-154, esp. p. 122 [hereafter Machina, 'Choice Under Uncertainty']; for a general history see e.g., 0yvind Bfllhren, 'Theory Development Processes in the Social Sciences: The Case of Stochastic Choice Theory' Journal of Economic Psychology 11 (1990): 1-34. 32 Gerd Gigerenzer, Zeno Swijtink, Theodore Porter, Lorraine Daston, John Beatty, and Lorenz Kruger, The Empire of Chance: How Probability Changed Science and Everyday Life, ldeas in Context Series (Cambridge: Cambridge University Press, 1989), p. 1 [hereafter Gigerenzer et al., The Empire of Chance]. Titis problern was first presented in Blaise Pascal, Pensees [1669] ed. by Louis Lafuma, (Paris: Editions de Seuil, 1962). 33

Gigerenzer et al., The Empire of Chance, p. 14.

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provided by Nicholas's cousin David Bemoulli in 1738 established the pattem that has dominated the Iiterature in the succeeding centuries. Rather than restricting hirnself to the objectively observable probabilities of the classical perspective, David Bemoulli hypothesised the existence of unobservable subjective influences, the predecessors of utility, which caused diminishing marginal satisfaction with decreases in wealth. 34 The modern treatment of decision-making under uncertainty is closely associated with the dassie treatment by von Neumann and Morgenstern, whose intention was to create a mathematically tractable model of idealised decisionmakers.35 This "expected-utility" model formed the basis for post-war research on decision-making,36 but the clarity of the formulation rapidly brought about sirnilar results to that experienced by Pascal' s classical probability: observed behaviour could not be reconciled with the mathematical specification.37 A

34 David Bernoulli, 'Specimen Theoriae Novae de Mensura Sortis' Comentarii Academiae Scientarum lmperialus Petropolitanae 5 (1738): 175-192 {translated as "Exposition of a New Theory on the Measurement of Risk" in Econometrica 22 (January 1954): 23-36 by Louise Sommer}. See generally Gigerenzer et al., The Empire of Chance, p. 15. 35 "We have practically defined numerical utility as being that thing for which the calculus of mathematical expectations is Iegitimate" John von Neumann and Oskar Morgenstern, Theory of Games and Economic Behaviour (Princeton, NJ: Princeton University Press, 1953), p. 28.

36 "It is no exaggeration to consider expected utility theory the major paradigm in decision making since the Second World War. lt has been used prescriptively in management science (especially decision analysis), predictively in finance and economics, descriptively by psychologists, and has played a central roJe in theories of measurable utility." Paul J.H. Schoemaker, 'The Expected Utility Model: lts Variants, Purposes, Evidence, and Limitations' Journal ofEconomic Literature 20(2) (June 1982): 529-563 at p. 529 [hereafter Schoemaker, 'Expected Utility']. 37 "It is hard to think. of a more notorious, long-standing, and often outright confused controversy in modern decision theory than the continuing debate on the meaning of "rationality" in choice under uncertainty." Mark J. Machina, "'Rational" Decision Making versus "Rational" Decision Modelling' Journal of Mathematical Psychology 24(2) (October 1981): 163-175 at p. 163. Foranillustration of this development over the last two decades compare the summary that "all in all, the evidence favours rationality" (Ward Edwards, 'Decision Making: Psychological Aspects' in David L. Sills (ed.), International Encyclopaedia ofthe Social Sciences, pp. 30-42, Vol. 4 (New York: Macmillan, 1968), p. 41) with Machina, 'Choice Under Uncertainty'. Seegenerally Mark J. Machina, 'Dynamic Consistency and Non-Expected Utility Models of Choice Under Uncertainty' Journal of Economic Literature 27 (December 1989): 1622-1668.

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bewildering succession of alterations and amendments has taken place in the last decades, with subjective treatments of probability joining the subjective estimation of utility. Although these formulations have varied widely, the general pattem has been often repeated of formal models having been specified, and then empirical research having shown that, in terms of those models, significant numbers of subjects have behaved 'irrationally' .38 The state of research has now developed to the stage where each of the four central principles of cancellation, transitivity, dominance, and invariance,39 have been systematically falsified in experimental tests. 40 The result of this

38 Nine variants are reviewed in Schoemaker, 'Expected Utility', pp. 530-538, summarised in table 1, p. 538. For a recent attempt and discussion see Mark J. Machina, 'A More Robust Definition of Subjective Probability' Econometrica 60(4) (July 1992): 745-780. A common criticism is that the anomalies result from incorrectly conducted experiments and inadequate incentives, but revised experiments by such critics have resulted in replication of the results; see e.g. David M. Grether and Charles R. Plott, 'Econornic Theory of Choice and the Preference Reversal Phenomenon' American Economic Review 69(4) (September 1979): 623-38, esp. p. 634 [hereafter Grether and Plott, 'Preference Reversal Phenomenon']; Robert J. Reilly, 'Preference Reversal: Further Evidence and Some Suggested Modifications in Experimental Design' American Economic Review 72(3) (June 1982): 576-596, esp. p. 582 [hereafter Reilly, 'Preference Reversal '].

Cancellation, alternatively terrned "independence", or the "sure-thing principle", refers to the cancellation of factors that result in the same outcome independently of one's choice; see e.g., Leonard J. Savage, The Foundations ofStatistics (New York: John Wiley, 1954); Machina, 'Choice Under Uncertainty', p. 127. Transitivity implies if x > y and y > z. then x > z. Intransitive preferences would expose the decision-maker to being used as a "money-pump"; see e.g., Amos Tversky, 'Intransitivity of Preferences' Psychological Review 76(1) (1969): 31-48, p. 31 [hereafter Tversky, 'lntransitivity of Preferences']. Dorninance is the principle of maximisation, and invariance means that the way a problern is presented should not affect its logical analysis; for a discussion of both see e.g., Amos Tversky and Daniel Kahneman, 'Rational Choice and the Frarning ofDecisions' Journal ofBusiness 59(4:2) (October 1986): S251-278 {reprinted in David E. Bell, Howard Raiffa, and Amos Tversky (eds.), Decision Making: Descriptive, Normative, and Prescriptive lnteractions, pp. 167-192 (Carnbridge: Carnbridge University Press, 1988)}, esp. p. S253 [hereafter Tversky and Kahneman, 'Rational Choice']. 39

40 Cancellation, see e.g., Maurice Allais, 'Le Comportement de l'Homme Rationnel Devant le Risque: Critique des Postulats et Axiomes de L'Ecole Americaine' Econometrica 21(4) (October 1953): 503-546, translated as Maurice Allais, 'The Foundations of a Positive Theory of Choice lnvolving Risk and a Criticism of the Postulates and Axioms of the American School' in Maurice Allais and Oie Hagen (eds.), Expected Utility Hypotheses and the Allais Paradox: Contemporary Discussions of

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enormous disparity between the theoretical specification of choice under uncertainty, and the observed behaviour of human decision-makers, has led two of the leading researchers in the field to renounce hope of reconciling theory and observation: Because framing effects and the associated failures of invariance are ubiquitous, no adequate descriptive theory can ignore these phenomena. On the other band, because invariance (or extensionality) is normatively indispensable, no adequate prescriptive theory should permit its violation. Consequently the dream of constructing a theory that is acceptable both descriptively and normatively appears unrealizable.4 1

Decisions under Uncertainty with Allais' Rejoinder, Theory and Decision Library, Vol. 21 (Dordrecht: D. Reidel, 1979), pp. 27-146; Daniel Ellsberg, 'Risk, Ambiguity, and the Savage Axioms' Quarterly Journal of Economics 15 (November 1961): 643-69, esp. pp. 650-656; Daniel Ellsberg, 'Risk, Ambiguity, and the Savage Axioms: A Reply' Quarterly Journal of Economics 77 (May 1963): 336-41. Transitivity: Tversky, 'Intransitivity of Preferences', esp. p. 40. Dominance: Amos Tversky and Daniel Kahneman, 'The Framing of Decisions and the Psychology of Choice' Science 211(4481) (30 January 1981): 453-458, esp. p. 454. lnvariance: Barbara J. McNeil, Stephen G. Pauker, Harold C. Sox Jr., and Amos Tversky, 'On the Elicitation of Preferences for Alternative Therapies' New England Journal of Medicine 306(21) (27 May 1982): 1259-62; Barbara J. McNeil, Stephen G. Pauker, and Amos Tversky, 'On the Frarning of Medical Decisions' in David E. Bell, Howard Raiffa, and Amos Tversky (eds.), Decision Making: Descriptive, Normative, and Prescriptive lnteractions, pp. 562-568 (Cambridge: Cambridge University Press, 1988); Amos Tversky and Daniel Kahneman, 'Rational Choice and the Frarning of Decisions' Journal of Business 59(4:2) (October 1986): 5251-278, esp. pp. 268-270; PeterBohm and Hans Lind, 'A Note on the Robustness of a Classical Framing Result' Journal of Economic Psychology 13 (1992): 355-361. 41 Tversky and Kahneman, 'Rational Choice', p. S272 {185}. For generat reviews of the theoretical and empirical developments, see e.g., Jonathan St. B.T. Evans, Stephen E. Newstead, and Ruth M.J. Byme, Human Reasoning: The Psychology of Deduction (Hillsdale, NJ: Lawrence Erlbaum Associates, 1993); Jonathan St. B.T. Evans, Bias in Human Reasoning: Causes and Consequences (Hillsdale, NJ: Lawrence Erlbaum Associates, 1989); David Kahneman, Paul Slovic, and Amos Tversky, (eds.), Judgement under Uncertainty: Heuristics and Biases (Cambridge: Cambridge University Press, 1982); David E. Bell, 'Disappointrnent in Decision Making Under Uncertainty' in David E. Bell, Howard Raiffa, and Amos Tversky (eds.), Decision Making: Descriptive, Normative, and Prescriptive lnteractions, pp. 358-383 (Cambridge: Cambridge University Press, 1988); Hai R. Arkes and Kenneth R. Harnmond, (eds.), Judgement and Decision Making: An lnterdisciplinary Reader (Cambridge: Cambridge University Press, 1986); Robin M. Hogarth, Judgement and Choice: The Psychology of Decision, 2nd ed. (Chichester: John Wiley & Sons, 1987); Robin M. Hogarth, (ed.), lnsights into Decision Making: A Tribute to Hillel J. Einhorn (Chicago, IL: Chicago University Press, 1990); Robin M. Hogarth and Melvin W. Reder, (eds.), Rational Choice: The

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It should come as no surprise to readers who have followed the Wason selection task discussion that "framing effects and the associated failures of invariance are ubiquitous": the attempt to discover a domain generat choice ability parallels the attempt to find a general ability to solve the propositional calculus. The "dream of constructing a theory that is acceptable both descriptively and normatively" is thus realisable, but in another form than expected by Tversky and Kahneman, and most investigators of choice under uncertainty. Evolutionary psychology suggests that the search since Pascal and Bemoulli for a general "choice under uncertainty" psychological capacity is profoundly misguided. Such an ability is unlikely to exist; instead many domain specific cognitive programs will deal with particular choice problems which were relevant in the environment of evolutionary adaptedness. It is these specialised cognitive programs which can be expected tobe responsible for the "biases" and "effects" that have been observed, such as the "reflection effect", where "when choosing between two lass situations, people seek risk. When affered two gain options, they avoid risk".42 A particularly active field of research, where subjects are observed to systematically choose one alternative but pay a higher price for the other, is the "preference reversal phenomenon". 43

Contrast Between Economics and Psychology (Chicago & London: Chicago Press, 1987).

University of

42 Anne Toland and Patrick O'Neill, 'A Test of Prospect Theory' Journal of Economic Behavior and Organization 4(1) (March 1983): 53-56 at p. 55. Seegenerally Daniel Kahneman and Amos Tversky, 'Prospect Theory: An Analysis of Decision Under Risk' Econometrica 47(2) (March 1979): 263-291, esp. pp. 268-269 [hereafter Kahneman and Tversky, 'Prospect Theory'].

43 See e.g., Paul Slovic and Sarah Lichtenstein, 'The Relative Importance of Probabilides and Payoffs in Risk-Taking' Journal of Experimental Prychology: Monograph Supplement 78(2) (November 1968): 596-605; Paul Slovic and Sarah Lichtenstein, 'Preference Reversals: A Broader Perspective' American Economic Review 73(4) (September 1983): 596-605; Sarah Lichtenstein and Paul Slovic, 'Reversals of Preference Between Bids and Choices in Gambling Decisions' Journal of Experimental Psychology 89(1) (January 1971): 46-55; Sarah Lichtenstein and Paul Slovic, 'Response-Induced Reversals of Preference in Gambling: An Extended Replication in Las Vegas' Journal of Experimental Psychology 101(1) (November 1973): 16-20; Grether and Plott, 'Preference Reversal Phenomenon'; John C. Mowen and James W. Gentry, 'Investigation of the PreferenceReversal Phenomenon in a New Product Introduction Task' Journal of Applied Psychology 65(6) (1980): 715-722; Reilly, 'Preference Reversal'; Werner W. Pommerehne, Friedrich Schnieder, and Peter Zwiefel, 'Economic Theory of Choice and

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Although adequate investigation requires empirical research by psychologists, some characteristics of this choice behaviour are to be expected on the basis of a priori reasoning and prior research.44 There will probably be no general "probability function", and probabilities which are presented as facts can be expected to be interpreted with caution, with a bias toward the status quo. This follows from the fact that there were no objective probability estimates in the environment of evolutionary adaptedness, and the Iikelihood of something occurring would have been estimated on the basis of personal experience or communication from others - both highly error-prone sources. These conjectures would appear tobe supported by the failure to construct an invariant or canonical representation of problems,45 and the bias towards certainty and the status quo. 46 Similarly, transactions which involve exchange will be interpreted with caution, with a tendency towards the status quo. The ex ante promise to be provided with x in exchange for y is quite different from the ex post possession of x and loss of y; indeed this is the basis of the "Iook for cheaters" Darwinian algorithm discussed above. Similar reasons could underlie the "reflexion effect" and the "preference reversal phenomenon". A further prediction is that the nature of the maximisation process will depend upon the domains being considered. Maximisation for the genet will often appear as rational, for example, whereas that for the kin-group or group vehicles may seem altruistic or irrational. The purchase of an item such as a car could be influenced by all three Ievels: as a functional means of transport

the Preference Reversal Phenomenon: A Reexamination' American Economic Review 72(3) (June 1982): 569-574; Raphael Bostic, Richard J. Herrnstein, and R. Duncan Luce, 'The Effect on the Preference-Reversal Phenomenon of using Choice Indifferences' Journal of Economic Behavior and Organization 13(2) (March 1990): 193-212; Amos Tversky, Paul Slovic, and Daniel Kahneman, 'The Causes of Preference Reversal' 80(1) (March 1990): 204-217. 44 Previous interpretations of these choice anomalies including an evolutionary element include Margolis, Patterns, Thinking, and Cognition, pp. 141-187.

45 For example, "the failure to construct a canonical representation in decision problems contrasts with other cognitive tasks in which such representations are generated automatically and effortlessly." Tversky and Kahneman, 'Rational Choice', p. S256.

46 See e.g., Amos Tversky, 'Loss Aversion in Riskless Choice: A Referencedependent Model' Quarterly Journal of Economics 106(4) (1991): 1039-1061; William Samuelson and Richard Zeckhauser, 'Status Quo Bias in Decision Making' Journal of Risk and Uncertainty 1 (1988): 7-59; Kahneman and Tversky, 'Prospect Theory', esp. fig. 3 p. 279 and fig. 4. p. 283.

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its purchase represents somatic effort; as a symbol to potential mates, reproductive effort; and as support for one's group, community effort.47 In addition, insofar as somatic resources are being maximised, judgements about these are inherently made on a relative scale, rather than on the absolute scales generally assumed by decision theorists and economists.48 In sum, the essence of conventional investigations of choice under uncertainty is the ascription to Homo oeconomicus of cognitive abilities that appear logical and self-evident, and to deduce choice behaviour on this basis. 49 This assumption has been convincingly falsified in empirical tests, while it appears likely that the experimental results will be interpretable as the result of the cognitive programs of Homo biologicus.

b) Excess Volatility in Securities Markers The rejoinder of economists when confronted with these choice anomalies is generally that the experiments have been inappropriately conducted, and that so long as markets behave as if typical individuals maximise, then the details of individual psychologies are immaterial - Friedman's "as-if' assumption. 50 This approach would also appear to mesh closely with the behaviour of advertisers; see generally Vance Packard, The Hidden Persuaders, Rev. ed. (New York: Pocket Books, 1980); Michael Schudson, Advertising, the Uneasy Persuasion: lts Dubious Impact on American Society (New York: Basic Books, 1984). 47

48 For an approach stressing the importance of "positional goods" and other aspects of such relativities, see Tibor Scitovsky, The Joyless Economy: An lnquiry into Human Sarisfaction and Consumer Dissarisfaction (Oxford: Clarendon Press, 1976), esp. pp. 114-120, 134-136; Tibor Scitovsky, Human Desire and Economic Satisfaction: Essays on the Frontiers of Economics (Brighton, Sussex: Harvester Wheatsheaf, 1986), esp. pp. 120-135. 49 See e.g., J.M. Blatt, 'Expected Utility Theory Does Not Apply to All Rational Men' in Bemt P. Stigum and Fred Wenstop (eds.), Foundations of Utility and Risk Theory with Applications (Dordrecht: D. Reidel, 1983), esp. p. 107.

50 See above, p. 171. For methodological dicussions of the status of the maximisation assumption see e.g., Lawrence A. Boland, 'On the Futility of Criticizing the Neoclassical Maximisation Hypothesis' American Economic Review 71 (5) (December 1981): 1031-1036; Bruce J. Caldwell, 'The Neoclassical Maxirnisation Hypothesis: Comment' American Economic Review 73(4) (September 1983): 824-827. As an example of the minority of econornists who take the choice anomalies seriously, Arrow argues that "an important class of intertemporal markets shows systematic deviations from individual rational behavior and that these deviations are consonant with evidence

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The question of whether this assumption is in fact justified is thus of central importance to the case for Homo oeconomicus. Securities markets provide a particularly appropriate domain for such analysis, as four factors aid the testing of the utility maximising behaviour of economic agents: (1) anomalies are unlikely to arise through transaction costs or similar market imperfections, due to the volume of trading, excellent information, and standardisation of products; (2) market participants are a subset of the general population, many of whom specialise in securities transactions; (3) large amounts of accurate data, often extending over decades, facilitate empirical analysis; and (4) the existence of weil specified hypotheses based on efficient markets theories opens the possibility of discriminating tests between hypotheses. Together these factors mean that if models based on Homo oeconomicus can be falsified in securities markets, then they are highly unlikely to perform better in other parts of the economy. The assumption to be tested is that financial markets are efficient, in the sense that: The prices of securities in such markets are equal to their intrinsic values. For stocks, prices should reflect a rational forecast of the present value of future dividend payments. The efficient market hypothesis has also been traditionally associated with the assertion that future price changes are unpredictable.s 1

from very different sources collected by psychologists" (Kenneth 1. Arrow, 'Risk Perception in Psychology and Economics' Economic lnquiry 20 (January 1982): 1-9, p. 8). Sirnilarly Frey and Eichenherger contend that aggregate phenomena may be heavily influenced by "non-rational" choice behaviour, and suggest that social institutions may have emerged to overcome such anomalies; see Bruno S. Frey and Reiner Eichenburger, 'Should Social Scientists Care About Choice Anomalies?' Rationality and Society 1(1) (July 1990): 101-122. sl Wemer F.M. De Bondt and Richard H. Thaler, 'Anomalies: A Mean-Reverting Walk Down WallStreet' Journal ofEconomic Perspectives 3(1) (Winter 1989): 189-202, p. 189 [hereafter Oe Bondt and Thaler, 'Mean-Reverting Walk']. The demonstrated unpredictability of certain price movements has led some theorists to revise the hypothesis so that prices may be predictable and yet markets efficient; see ibid., pp. 189 ff. For a general review of efficient markets theories and current research see e.g., Eugene F. Fama, 'Efficient Capital Markets: II' Journal of Finance 46(5) (December 1991): 1575-1617; Stephen F. LeRoy and William R. Parke, 'Stock Price Volatility: Tests Based on the Geometrie Random Walk' American Economic Review 82(4) (September 1992): 981-992; Kenneth A. Froot and Maurice Obstfeld, 'Intrinsic Bubb1es: The Case of Stock Prices' American Economic Review 81(5) (December 1991): 1189-1214.

190

VI. Homo Biologicus and Human Characteristics

In a seminal series of articles Shiller compared the volatility predicted from the efficient markets model with that of observed share prices.52 He represented a simple "random walk" efficient markets model by considering the total real retum R, on an initial share investment of P,, the real dividends paid on the stock D,, a constant discount rate r, and a mathematical expectation term E,, specifying that: [6.1 J

E, R,

[6.2]

R,

=(PI+

=r

P, + D,) I P,

1 -

The price of the stock P, is the optimal forecast P, • of the true investment value: [6.3]

P, = E, P,·

and P,· is the present value, discounted at rate r, of actual future dividends: [6.4]

D p• = --''

(1 +R)

+

D, (1

+ I

+ r) 2

D, - 2

+ --'-~

(1

+

r)3

+

Shiller reasoned that the volatility of the forecast can not exceed that of the variable forecasted, i.e., the random walk model predicts that the variability of P, must be less than that of P/. This can be formally demonstrated, but is more intuitively apparent in Shiller' s argument that: lf, for example, the forecast of x were as volatile as x but only weakly correlated with it, then high values of the forecast would tend to be associated with negative forecast

52 The following discussion concentrates on Shiller' s analysis of the relation between price and intrinsic value, following Robert J. Shiller, 'The Volatility of Stock Market Prices' Science 235(4784) (2 January 1987): 33-37 [hereafter Shiller, 'Volatility of Stock Market Prices'], except where specified. Complementary research has investigated the second prediction of non-predictability, and has demonstrated the existence of statistically significant seasonal effects such as the rise in prices in the first days and month of a calendar year termed the "January effect"; see Richard H. Thaler, 'Anomalies: The January Effect' Journal ofEconomic Perspectives 1(1) (Summer 1987): 197-201. For other periodic effects and the "mean reversion effect" see Richard H. Thaler, 'Anomalies: Seasonal Movements in Security Prices li: Weekend, Holiday, Turn of the Month, and Intraday Effects' Journal of Economic Perspectives 1(2) (Fall1987): 169-177; Richard H. Thaler, 'Anomalies: The Winner's Curse' Journal of Economic Perspectives 2(1) (Winter 1988): 191-202; De Bondt and Thaler, 'Mean-Reverting Walk'.

2. Homo Biologicus versus Homo Oeconomicus

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errors, low values with positive forecast errors. This would mean that the forecast error was somewhat forecastable, and so the forecast could not be optimal.53

It is apparent from figure 6.1 that real stock prices (P,) are dramatically more variable than their predicted counterparts (P,) which approximate a smooth trend line. 54 The P ',· dashed line represents an adjusted form of perfect foresight model, in which the expected variability of real interest rates is incorporated. While substantially more variable than P,·, P ',· is still less variable than P,, and is essentially uncorrelated with P, except for particular periods such as 1920-1929 and 1982-1986.55

e 8o

.!!

ö

... "0

= ~

.E

=

"0

.E

1880

1900

1920

1940

1960

1980

I (ye1r)

Figure 6. I Real Stock Prices and their Perfeet Foresight Counterparts 1871 to 198656

53

Shiller, 'Volatility of Stock Market Prices', p. 33.

Because of the lagged weighting panem of equation 6.4, there are relatively few independent observations to form the basis of a statistical test, and the annual variations of P, * cannot be directly compared to those of P,·. Nevertheless, estimations of volatility indicate that P,· is five to thirteen times more variable than implied by the efficient markets model. See Robert J. Shiller, 'Do Stock Prices Move Too Much tobe Justified By Subsequent Changes in Dividends?' American Economic Review 71(3) (June 1981): 421-436, table 2 p. 431. 54

55

Shiller, 'Volatility of Stock Market Prices', p. 35.

Reprinted, with permission from the AAAS and the author, from Robert J. Shiller, 'The Volatility of Stock Market Prices' Science 235(4784) (2 January 1987): 33-37, fig. 1 p. 34 (copyright 1987 by the AAAS). 56

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VI. Homo Biologicus and Human Characteristics

After considering other models which respond to various criticisms of these excess volatility results, 57 Shiller concludes that: The price P, or its ratio to dividend P, ID,_ 1 generally appears to show too much variability given its correlation with its perfect-foresight Counterpart under any of the models considered here. 58

Shiller explains this excess volatility in stock markets and similar phenomena in other financial domains through the creation of models where "speculative prices tend to be mixtures of popular opinion and fact about fundamental value". 59 He suggests a division between "smart money" investors, who behave rationally but are constrained by their wealth, and "ordinary investors", who possess "popular models" of markets and are liable to fads and other forrns of 'irrational' behaviour, because of social-psychological effects such as feedback or contagion.60 Although support for this hypothesis is difficult to establish through statistical tests, he draws on psychological and socialpsychological research, investor surveys, and case studies, constructing a plausible alternative model in order to support his argument. 61 While many economists still do not accept that 'irrational' behaviour is the reason for the failure of the efficient markets model,62 the difficulty of finding

57 For criticisms of Shiller's analyses see e.g., Alan W. Kleidon, 'Anomalies in Financial Economics: Blueprint for Change?' Journal of Business 59(4:2) (October 1986): S469-499, esp. pp. S489 ff; and the responses to Robert J. Shiller, 'Stock Prices and Social Dynamics' Brookings Papers on Economic Acrivity 2 (1984): 457-498 [hereafter Shiller, 'Social Dynamics']. Shiller, for example, controls for trend effects by calculating price-dividend ratios ('Volatility of Stock Market Prices' , pp. 34-35), and repeats the analysis using consumption-based discount rates rather than those from the financial markets (ibid., pp. 35-36). 58

Shiller, 'Volatility of Stock Market Prices', p. 36.

Robert J. Shiller, Marker Volatility (Cambridge, MA: MIT Press, 1990), p. 431 [hereafter Shiller, Marker Volarility]. 59

60 See genera11y Shiller, 'Socia1 Dynamics', pp. 477-481. Statistical analysis of the model confrrms that such over-reaction dynanlies are consistent with the data (ibid., pp. 481 ff .).

61

See Shiller Market Volarility, esp. pp. 7-49, 371-374, 379-432.

The response of those committed to the conventional paradigm has generally been to attempt to construct rational choice models whose particular characteristics Iead to 'irrational' aggregate behaviour. Scharfstein and Stein, for example, formulate a model in which professional managers follow their colleagues' choices because this enhances their reputations and thus careers, rather than making independent decisions which would 62

2. Homo Biologicus versus Homo Oeconomicus

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alternative explanations, tagether with the increasing weight of evidence for irrational effects in securities and other markets,63 strongly supports the implied inadequacy of Homo oeconomicus. From the perspective of evolutionary psychology and Homo biologicus, panic and interpersonal influence are very probably central to such market behaviour, although not necessarily the complete explanation. lt has been demonstrated above, with respect to panic disorder and

agoraphobia, that extreme examples of panic are interpretable as the result of individual maximisation, and it is likely that similar loss-minimising cognitive processes give rise to panic in the financial sphere. The obedience of individuals to authority, and their conformity to group views, have also been given functional interpretations - in terms of mechanisms for the group vehicle - and appear likely to underlie the faddish aspects of financial market dynarnics. Thus it appears that important elements of non-rational behaviour in securities markets are incompatible with Homo oeconomicus but can be interpreted in terms of Homo biologicus, although a full comparison of the models must be the subject of future research. c) Household Behaviour and Family Altruism

In an ironic twist, while the previous two 'economic' subsections involved the detailed criticism of hypotheses based on Homo oeconomicus, this and the following 'non-economic' subsections accept models based on the economic approach, but show that their assumptions are incompatible with Homo biologicus.

expose them to criticism; David S. Scharfstein and Jeremy C. Stein, 'Herd Behaviour and Investment' American Economic Review 80(3) (June 1990): 465-479. While the authors attempt to ground this in Keynes' discussion of reputational effects on rational investors (ibid., p. 465), a close reading indicates that Keynes was in fact very aware of mass psychology in the stock market: "A conventional valuation which is established as the outcome of the mass psychology of a !arge number of ignorant individuals is Iiable to change violently as the result of a sudden fluctuation of opinion due to factors which do not really make much difference to the prospective yield" (John Maynard Keynes, The General Theory of Employment, lnterest and Money, The Collected Writings of John Maynard Keynes, Vol. VII (London: Macmillan, 1936), pp. 153-154). 63 See e.g., Kenneth D. West, 'Dividend Innovations and Stock Price Volatility' Econometrica 56(1) (January 1988): 37-61, esp. p. 58. 13 Elworthy

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VI. Homo Biologicus and Human Characteristics

Becker' s refonnulation of rnicroeconornics in tenns of households and farnilies is a radical and elegant step which fonns the base of the "new home econornics" and which has implications far beyond pure econornic theory.64 At the centre is the unification of production and consumption decisions in households rather than individuals: on the production side, Becker postulates the existence of a "household production function"; 65 on the consumption side Becker develops his new model of consumer choice in tenns of demand for fundamental resources (commodities) discussed above (page 172). Becker' s choice of the entire hausehold does not imply that he is unaware of conflicts of interests between its members - on the contrary, Becker and his associates are famous, if not notorious, for their analyses of marriage and divorce, division of labour within the farnily, fonns of farnily organisation such as polygyny, and parent-offspring discord. 66 The focus on the household results, instead, from a realisation that it represents an entity with a general commonality of interest, and that this unitary character is sufficient for the hausehold rather than the individual to be the unit for which maxirnising behaviour is most appropriately assumed. Becker bases this unitary nature on shared interests that a man and a woman have in marriage, through begetting

See e.g., Manfred Tietzel, 'Wirtschaftstheorie als allgemeine Theorie des menschlichen Verhaltens: Eine Analyse der "New Horne Economics"' Zeitschrift für Wirtschaftspolitik 32(3) (1983): 225-242; Douglas W. Allen, 'An Inquiry Into the State' s RoJe in Marriage' Journal of Economic Behavior and Organization 13(2) (March 1990): 171-179; Yoram Ben-Porath, 'Economics and the Family - Match or Mismatch? A Review ofBecker's A Treatise on the Family' Journal ofEconomic Literature 20 (March 1982): 52-64. 64

65

Michael and Becker, 'New Theory', p. 381 ff. {134 ff.).

See e.g., Becker, Economic Approach; Gary S. Becker, A Treatise on the Family (Cambridge, MA: Harvard University Press, 1981) [hereafter Becker, Treatise on the Family]; Gary S. Becker and Nigel Tomes, 'Child Endowments and the Quantity and Quality of Children' Journal of Political Economy 84(4) (1976): S143-162; Gary S. Becker, Elisabeth M. Landes, and Robert T. Michael, 'An Economic Analysis of Marriage Instability' Journal of Political Economy 85(6) (1977): 1141-1187; Gary S. Becker, 'A Theory of Social Interactions' Journal of Political Economy 82(6) (November-December 1974): 1063-1093 [hereafter Becker, 'Social Interactions' ]; Becker, 'Economics and Sociobiology'; Gary S. Becker and Robert J. Barro, 'A Reformulation of the Economic Theory of Fertility' Quarterly Journal of Economics 103(1) (February 1988): 1-25 [hereafter Becker and Barro, 'Theory of Fertility']. 66

2. Homo Biologicus versus Homo Oeconomicus

195

and raising children, and the altruistic nature of the relations within the family. 67 This model accords with large amounts of empirical data from a wide variety of countries which have been used to test particular hypotheses derived from the general framework. 68 The approach has a fundamental flaw, however: in order to reconcile his theoretical formulation with the selfish individualistic maximising of Homo oeconomicus, Becker assumed that a family could be represented by a leader who maximises his or her individual utility: A family with a head can be said to maximise "its" consistent and transitive utility function of the consumption of different members subject to a budget constraint defined on family variables. The "farnily's" utility function is identical with that of one member, the head, because his concem for the welfare of other members, so to speak, integrates all the members' utility functions into one consistent "family" function69 •

That this is a patent fiction is illustrated by Becker' s sophisticated treatment of behaviour within the family where the confluences of interests vie with divergences of interest, as in the "rotten kid theorem" .70 In fact the explicit recognition of altruistic behaviour towards family members and the resulting interrelationship of utility functions means that there is an irreconcilable break between these hypotheses and the assumptions embodied in Homo oeconomicus. In contrast it should be clear that the combination of somatic effort as a mechanism for the genet, and reproductive effort as a mechanism for the kin-group, show precisely the sources of the cornmonalities and differences of interest that Becker so elegantly analyses. Becker's household maximisation is thus interpretable as kin-group

67 See Becker, Treatise on the Family, esp. p. 93, p.l72; Becker and Barro, 'Theory of Fertility', pp. 2-3. 68 See e.g., Becker, Treatise on the Family, passim; Robert T. Michael, 'Why Did the U.S. Divorce Rate Double Within A Decade?' Research in Population Economics 6 (1988): 367-399; Theodore W. Schultz, (ed.), Economics of the Family: Marriage, Children, and Human Capital (Chicago, IL: Chicago University Press, 1975); James J. Heckman, V. Joseph Hotz, and James R. Walker, 'New Evidence on the Timing and Spacing of Births' American Economic Review: Papersand Proceedings 75(2) (1985): 179-184. 69

Becker, 'Social Interactions', p. 1079.

Becker, 'Econornics and Sociobiology', pp. 820-821; Becker, Treatise on the Family, p. 183-191; Becker, 'Social Interactions', esp. pp. 1074-1083. 70

196

VI. Homo Biologicus and Human Characteristics

maximisation, and co-exists with conventional individualistic maximisation for the genet. Both forms of maximisation use the same individuals as mechanisms, but their functional objectives are different, which means that they must be analysed in different ways, as Becker recognises. In sum, the ad hoc model of farnily behaviour that Becker appears to have based on Observations of actual behaviour and sociobiological analysis,71 resulting in appropriate modifications to Homo oeconomicus, is exactly mirrored in Homo biologicus, and there is every expectation that an explicitly evolutionary model could facilitate further progress in this important field. d) War

Well over two millennia ago Thucidides cast bis analysis of the Pelopponesian war in terms of the interests of the principal actors, Athens and Sparta, although at the same time recognising the importance of intemal social and political disunity within the two states.72 The school within international relations which continues this tradition is generally termed realism or neorealism/ 3 and the branch of this Iiterature devoted to war is of particular concem here. Bueno de Mesquita has developed a comprehensive expected-utility approach to war, in which the difficulties of a state acting as a purposive actor are explicitly confronted. 74 He recognises that states have very often divided 71 See Becker, Treatise on the Family, esp. pp. 14-15, 172-173, 237-256; Becker, 'Economics and Sociobiology', pp. 817-818; Gary S. Becker, 'Aitruism, Egoism, and Genetic Fitness: Economics and Sociobiology' Journal of Economic Literature 14(3) (September 1976): 817-826. 72 Thucidides, The Peloponnesian War, trans. by Richard Crawley and T.E. Wiek (New York: Random House, 1984).

73 See generally, Kenneth N. Waltz, Man, the State, and War: A Theoretical Analysis (New York: Columbia University Press, 1959); Waltz, International Politics; Robert George Gilpin, War and Change in World Politics (Cambridge: Cambridge University Press, 1981); Robert Owen Keohane, (ed.), Neorealism and its Critics (New York: Columbia University Press, 1986); Morgenthau, Politics among Nations; Edward Hallett Carr, The Twenty Years' Crisis, I919-1939: An Introduction to the Study of International Relations (London: Macmillan, 1951). Cf. Richard K. Ashley, 'Political Realism and Human Interests' International Studies Quarterly 25(2) (June 1981): 204-236.

74 Seegenerally Bueno de Mesquita, War Trap; Bruce Bueno de Mesquita, 'War and the Fate of Regimes: A Comparative Analysis' American Political Science Review 86(3)

2. Homo Biologicus versus Homo Oeconomicus

197

leadership, as captured in Allison's "bureaucratic politics" hypothesis,75 but assumes that in times of war: "(a) war decision making is dominated by a single, strong Ieader; (b) Ieaders arerational expected-utility maximisers". 76 Bueno de Mesquita's work offers strong parallels to Becker's, and similar conclusions can be drawn in both cases. The characteristics of states as unitary actors in times of war precludes the existence of important interest differences within states, just as family maximisation excludes within-family conflict. Yet in periods of peace it is exactly these individual and group interest differences that form the foundation of economic and political analysis. This contrast between maximising and unitary state behaviour with respect to "national interests", and cooperative international behaviour in realms such as pollution, is an important theme in international relations research. 77 Indeed collective action theory, which investigates the process of organising individuals to achieve

(1992): 638-645; Bruce Bueno de Mesquita and David Lalman, 'Domestic Opposition and Foreign War' American Political Science Review 84 (1990): 747-765; Bruce Bueno de Mesquita and David Lalman, War and Reason (New Haven, CT: Yale University Press, 1992). 75 Graham Allison, 'Conceptual Models and the Cuban Missile Crisis' American Political Science Review 63(3) (September 1969): 689-718, esp. pp. 707-715. 76

Bueno de Mesquita, War Trap, p. 20.

See e.g. Felix E. Oppenheim, 'National Interest, Rationality, and Morality' Political Theory 15(3) (August 1987): 369-389, esp. pp. 374-376; Stephen D. Krasner, Defending the National lnterest: Raw Materials Investments and U.S. Foriegn Policy (Princeton, NJ: Princeton University Press, 1978), esp. 5-34; A.F.K. Organski and Jacek Kugler, The War Ledger (Chicago: Chicago University Press, 1980); Robert Owen Keohane and Joseph S. Nye, Power and Independence: World Politics in Transition (Boston: Little Brown, 1977); Robert Owen Keohane and Joseph S. Nye, "'Power and lndependence" Revisited' International Organization 41(4) (Autumn 1987): 725-753; Robert Owen Keohane, 'Reciprocity in International Relations' International Organization 40(1) (Winter 1986): 1-27; and the contributions in Stephen D. Krasner, (ed.), International Regimes (lthaca, NY: Comell University Press, 1983). 77

78 Seegenerally Olson, Logic. One of the most productive applications of this theory in international relations has been alliance formation and behaviour, which faces exactly the same methodological difficulties as war-making; see e.g., Mancur Olson, Jr., and Richard Zeckhauser, 'An Economic Theory of Alliances' Review of Economics and Statistics 48(3) (August 1966): 266-279; Pau1 F. Diehl, 'Sharing the Defence Burden in Nato: The Problem of the "Free Rider"' in Walter Goldstein (ed.), Fighting Allies: Tensions within the Atlantic Alliance, pp. 25-38 (London: Brasey's Defence Publications, 1986); Todd Sandler and Jon Cauley, 'On the Econornic Theory of

198

VI. Homo Biologicus and Human Characteristics

common goals,78 is one of the most important examples of the economic approach in political science.79 1t should thus be astonishing that, where the achievement of national interest calls for personal sacrifices extending to loss of life and limb, in countless examples across time and space individuals have set aside their personal interests and participated in or supported war. Committed economists have attempted to analyse war in tenns of the egoism of Homo oeconomicus: Armies must be analyzed as collections of independent individuals who are, in some senses, as much as war with one another and their own Ieaders as they are with the enemy forces. 80

Not only is such an approach incompatible with unitary state behaviour, it is also unconvincing even to other economists, and does not mesh with

Alliances' Journal ofConflict Resolution 19 (1975): 330-348; Todd Sandler, Jon Cauley, and John Forbes, 'In Defense of a Collective Goods Theory of Alliances' Journal of Conflict Resolution 24(3) (1980): 537-547; Joe Oppenheirner, 'Collective Goods and Alliances: A Reassessment' Journal of Conflict Resolution 23(3) (September 1979): 387-407. 79 A large political science literature, for example, discusses the role states play in solving collective action problems: see e.g., Andrew Schotter, The Economic Theory of Social Institutions (Cambridge: Cambridge University Press, 1981); Andrew Schotter, 'The Evolution of Rules' in Richard N. Langlais (ed.), Economics as a Process: Essays in the New /nstitutional Economics, pp. 117-133 (Cambridge: Cambridge University Press, 1986); Dennis C. Mueller, Public Choice II: A Revised Edition of "Public Choice" (Cambridge: Cambridge University Press, 1989), esp. pp. 9-42. One field of debate that shows the inherent selfishness of Homo oeconomicus is "why individuals vote?" The problern arises because the voter incurs a positive cost, but the direct personal benefits are negligible; see e.g., Anthony Downs, An Economic Theory of Democracy (New York: Harper & Row, 1957), passim; John A. Ferejohn and Morris P. Fiorina, 'The Paradox of Not Voting: A Decision Theoretic Analysis' American Political Science Review 68(2) (June 1974): 525-536; Paul E. Meehl, 'The Selfish Voter Paradox and the Thrown-Away Vote Argument' American Political Science Review 71(1) (March 1977): 11-30; Robert E. Goodin and K.W.S. Roberts, 'The Ethical Voter' American Political Science Review 69 (1975): 926-928; Thomas Schwartz, 'Your Vote Counts on Account of the Way It is Voted: An Institutional Solution to the Paradox of Not Voting' Public Choice 54 (1987): 101-121; Artbur Schram and Frans van Winden, 'Why People Vote? Free Riding and the Production and Consumption of Social Pressure' Journal of Economic Psychology 12(4) (December 1991): 575-620.

80 Geoffrey Brennan and Gordon Tullock, 'An Economic Theory of Military Tactics: Methodological Individualism at War' Journal of Economic Behavior and Organization 3(2-3) (June-September 1982): 225-42.

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observations such as the widespread willingness to go to war, or the demonstrations of self-sacrifice by soldiers beyond normal social control. 81 That we instead see such behaviour as "normal", and even create expected utility models for states considering war, indicates how "natural" we consider such behaviour to be. From the standpoint developed in this work, the attribution of qualities such as patriotism, loyalty, and self-sacrifice to Homo biologicus is a logical result of selection having acted on the group vehicle. 82 An adequate model of war will thus require the modeHing of largely 'irrational' behaviour by those involved in fighting and the general population, and generally 'rational' behaviour by strategists and national leaders.83 Such an interpretation of the cognitive structures underlying war as community effort complements the comprehension, as less extreme forms of such effort, of such puzzling phenomena as cognitive dissonance,84

81 For the debate following the Brennanffulluck article, see M.W. Jackson, 'Chocolate Box Soldiers: A Critique of "An Economic Theory of Military Tactics"' Journal of Economic Behavior and Organization S(1) (March 19&7): 1-11; Gordon Tullock, 'Jackson and the Prisoner' s Dilemma' Journal of Economic Behavior and Organization 8(4) (December 1987): 637-640; Geoffrey Brennan, 'Methodological Individualism Under Fire: A Reply to Jackson' Journal of Economic Behavior and Organization S(4) (December 19&7): 627-635; William C. Mitchell, 'More on Military Tactics' Journal of Economic Behavior and Organization 11(2) (19&9): 293-296. For a general analysis of individual behaviour in battle see John Keegan, The Face of Battle: A Study of Agincoun, Waterloo, and the Somme (Harmondsworth, Middlesex: Penguin, 1976), esp. pp. 114-116, 274-284.

82 For discussions directly relevant to group aggression see, e.g., the contributions in Vernon Reynolds, Vincent Falger, and lan Vine, (eds.), The Sociobiology of Ethnocentrism: Evolutionary Dimensions of Xenophobia, Discrimination, Racism, and Nationalism (London: Croom Helm, 1987); Joseph Palmer Roberts, 'The Sociobiology of Ethnocentrism in an Indian City' Ethology and Sociobiology 11(6) (November 1990): 465-47&. 83 Empirical research fails to support the primacy of one single model for military disputes, and irnplicitly supports the existence of such complex determinants of war; see Paul Huth and Bruce Russett, 'General Deterrence between Enduring Rivals: Testing Three Competing Models' American Political Science Review &7(1) (March 1993): 61-73.

84 See e.g., Leon Festinger, 'A Theory of Social Comparison Processes' Human Relations 7(2) (May 1954): 117-140; Leon Festinger, A Theory of Cognitive Dissonance (Stanford, CA: Stanford University Press, 1957); Leon Festinger and James M. Carlsrnith, 'Cognitive Consequences of Forced Compliance' Journal of Abnormaland Social Psychology 5& (1959): 203-211.

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VI. Homo Biologicus and Human Cbaracteristics

ostracism,85 an underlying commitment to procedural justice independent of Substantive results, 86 or the willingness of individuals to engage in collective action. 87 The cognitive programs generated by such selection almost certainly engender an "agentic shift" analogous tothat hypothesised by Milgram in his experiments on obedience and conformity, and for sirnilar reasons: the

85 See e.g., Margaret Gruter and Roger D. Masters, 'Ostracism as a Social and Biological Pbenomenon: An lntroduction' Ethology and Sociobiology 7(3/4) (1986): 149-158 {reprinted in Margaret Gruter and Roger D. Masters (eds.), Ostracism: A Soeial and Biological Phenomenon, New York: Elsevier Science Publisbing, 1986}, and the accompanying articles.

86 See e.g., Tom R. Tyler, 'The Psycbology of Procedural Justice: A Test of the Group Value Model' Journal of Personality and Soeial Psychology 57(5) (1989): 830-838; Tom R. Tyler, 'Justice, Self-lnterest, and the Legitimacy of Legaland Political Authority' in Jane J. Mansbridge (ed.), Beyond Self-lnterest, pp. 171-179 (Cbicago: University of Cbicago Press, 1990); Tom R. Ty1er, Jonathan D. Casper, and Bonnie Fisber, 'Maintaining Allegiance toward Politica1 Authorities: The Ro1e ofPrior Attitudes and the Use of Fair Procedures' American Journal of Political Seience 33(3) (August 1989): 629-652; E. Allan Lind and Tom R. Tyler, The Soeial Psychology of Procedural Justice (New York: Plenum Press, 1988). 87 See e.g., Linnda R. Caporael, Robyn M. Dawes, Jobn M. Orbell, and Alpbons J.C. van de Kragt, 'Selfishness Examined: Cooperation in the Absence of Egoistic lncentives' Behavioral and Brain Seiences 12(4) (December 1989): 683-698; Linnda R. Caporael, Robyn M. Dawes, John M. Orbell, and Alpbons C.C. van de Kragt, 'Thinking in Sociality' Behavioral and Brain Seiences 12(4) (December 1990): 727-739; Robyn M. Dawes, 'The Potential Nonfalsity of the False Consensus Effect' in Robin M. Hogarth (ed.), /nsights into Deeision Making: A Tribute to Hillel J. Einhorn, pp. 179-197 (Cbicago: Cbicago University Press, 1990); Robyn M. Dawes, Alpbons J.C. van de Kragt, and Jobn M. Orbell, 'Not Me or Thee but We: The Importance of Group Identity in Eliciting Cooperation in Dilemma Situations: Experimental Manipulations' Acta Psychologica 68 (1988): 83-97; Robyn M. Dawes, Alpbons J.C. van de Kragt, and Jobn M. Orbell, 'Cooperation for the Benefit of Us -Not Me, or My Conscience' in Jane J. Mansbridge (ed.), Beyond Self-lnterest, pp. 97-110 (Cbicago: University of Cbicago Press, 1990); Robyn M. Dawes, Jobn M. Orbell, Randy T. Simmons, and Alpbons J.C. van de Kragt, 'Organizing Groups for Collective Action' American Political Seience Review 80(4) (December 1986): 1172-1185; Jobn M. Orbell, Alpbons J.C. van de Kragt, and Robyn M. Dawes, 'Explaining Discussion-Induced Cooperation' Journal of Personality and Soeial Psychology 54(5) (1988): 811-819; Alpbons J.C. van de Kragt, John M. Orbell, Robyn M. Dawes, S.R. Braver, and L.A. Wilson II, 'Doing Well and Doing Good as Ways of Resolving Social Dilemmas' in Henk A.M. Wilke, Dave M. Messick, and Christel G. Rutte (eds.), Experimental Soeial Dilemmas, pp. 177-202, Psychologie des Entschiedungsverbaltens und des Konfliktes; Psycbology of Decisions and Conflict, Vol. 3 (Frankfurt: Peter Lang, 1986).

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possession of traits which perrnitted effective united action bestowed evolutionrelevant advantages in the environment of evolutionary adaptedness. 88 Homo biologicus thus appears to present a better model of human psychology than Homo oeconomicus in times of war, a result that echoes the conclusions of the studies of choice under uncertainty, volatility in financial markets, and family altruism. 3. Linking the Human Seiences The previous section has discussed four specific forms of behaviour, and compared explanations in terms of the competing models Homo oeconomicus and Homo biologicus. Although in the spirit of the "discovery" of a "candidate" model no formal tests were conducted, it is to be hoped that the reader will agree that Homo biologicus carries the potential of being an improved model of man. Widespread acceptance ofthe approach advanced here requires, however, that his potential be translated into practice, so that the "normal science" of theory development and hypothesis testing can be conducted using an "operational" version of Homo biologicus. The maximisation conditions derived in chapter V are too abstract to be used in practical research: an economist investigating the insurance market, for example, would not be satisfied with an answer concerning responses to risk which was couched in terms of possible hazards in the environment of evolutionary adaptedness. 89

88 Some social psychological research explicitly recognises the existence of psychological mechanisms analogaus to the "agentic shift", such as the "risky shift" displayed by members of crowds; see e.g., Norris R. Johnson, James G. Stemler, and Deborah Hunter, 'Crowd Behavior as "Risky Shift": A Labaratory Experiment' Sociometry 40(2) (June 1977): 183-187. 89 For discussions of failures to maximise expected utility in the insurance markets see e.g., Howard C. Kunreuther and Paul Slovic, 'Economics, Psychology, and Pr6tective Behavior' American Economic Review: Papers and Proceedings 68(2) (May 1978): 64-69; Paul J.H. Schoemaker and Howard C. Kunreuther, 'An Experimental Study of Insurance Decisions' Journal of Risk and lnsurance 46(4) (December 1979): 603-18; Jobn C. Hershey and Paul J.H. Schoemaker, 'Risk Taking and Problem Context in the Domain of Lasses: An Expected Utility Analysis' Journal of Risk and Insurance 47 (1980): 111-132; Robert Eisner and Robert H. Strotz, 'Flight Insurance and the Theory of Choice' Journal of Political Economy 69(4) (August 1961): 355-368; B. Peter Pashigan, Lawrence Schkade, and George H. Menefee, 'The Selection of an Optimal

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Homo biologicus is an evolutionary model not only in the indirect sense, that it is founded on evolutionary theory and evolutionary psychology, but also in the direct meaning of being able to 'adapt' over time to changes in its environment, in this case progress in research. The effective development of such a model requires the linking tagether of normally separate disciplines, but not in the sense of interdisciplinary studies where perspectives from a nurober of disciplines are applied to one phenomenon such as aggression. 90 An attempt to create a unified human science would also be unlikely to be successful, due to the diversity of the disciplines and objectives involved. An appropriate path, in contrast, would seem to be to build a unified model of man, and for each discipline to contribute facets of its 'character' appropriate to its own knowledge and expertise.9t A major barrier to such disciplinary integration is methodological: many social scientists develop verbal analyses with little or no formal specifications or empirical tests. Although extremely flexible, it is not possible to derive from them the falsifiable models required for scientific research. Loyal economists may contend that the sophisticated analytical techniques of neoclassical economics would be the appropriate foundation, but four important limitations prevent them from providing a common methodology: Firstly, economic models are inherently flat rather than hierarchical, so that one Ievel of analysis (e.g. states, households or individuals) is analysed at a time: states are unitary maximisers with respect to war, families are unitary maximisers concerning altruism, individuals are unitary maximisers as consumers. Adequate modelling of Homo biologicus requires, in contrast, the handling of multiple Ievels. This means, for example, that as a crisis comes

Deductib1e for a Given Insurance Policy' Journal of Business 39(1) (January 1966): 35-44. 90 For an unsuccessful attempt of this nature, see Jo Groebel and Robert A. Hinde, (eds.), Aggression and War: Their Biological and Socia/ Bases (Cambridge: Cambridge University Press, 1989).

91 Similar suggestions for a "vertica1 integration" of disciplines have been made by, for examp1e, Jerome H. Barkow, Darwin, Sex, and Status: Biological Approaches to Mind and Culture (Toronto: University of Toronto Press, 1989), pp. 3-5, passim; Jerome H. Barkow, Leda Cosrnides, and John Tooby, 'Introduction: Evo1utionary Psychology and Conceptual Integration' in Jerome H. Barkow, Leda Cosmides, and John Tooby (eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, pp. 3-18 (Oxford: Oxford University Press, 1992), p. 4; and Tooby and Cosmides, 'Foundations of Culture', esp. pp. 19-24.

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closer to war, both within-group cooperation and between-group competition should become stronger. Secondly, economic analysis is normally "comparative-static" in form, where one parameter such as price is adjusted, while other factors are assumed to remain the same. The human sciences require models that are inherently dynarnic, not only with respect to behaviour, but also with respect to cognitive processes. It has been hypothesised above that the development of an individual implies differing amounts of somatic, reproductive, and community effort over time. Taking the hypotheticallifetime in figure 5.1 as an example (page 119), this would imply cognitive processes that emphasised somatic effort in childhood, reproductive effort in maturity, and so on. The potential importance of such effects is recognised in, for example, economic life-cycle models, 92 but the technical treatments of these analyses show the difficulty of dynarnic analyses of both psychology and behaviour. Thirdly, economic models are generally linear, whereas non-linear analysis shows that even very simple models may generate extremely complex behaviour. 93 Chaos theory indicates that wherever hierarchical structures are

92 See e.g., Albert Ando and Franeo Modigliani, 'The 'Life Cycle' Hypothesis of Saving: Aggregate Implications and Tests' American Economic Review 53 (March 1963): 55-84; Franeo Modigliani, 'Life Cycle, Individual Thrift, and the Wealth of Nations' American Economic Review 76(3) (June 1986): 297-313; Lars Söderström, 'The Life Cycle Hypothesis and Aggregate Household Saving' American Economic Review 72(3) (1982): 590-596; Milton Friedman, A Theory of the Consumption Function (Princeton, NJ: Princeton University Press, 1957). See also Betsy B. White, 'Empirical Tests of the Life Cycle Hypothesis' American Economic Review 68 (1978): 547-560.

Although "chaos theory" has been applied to a wide range of disciplines, it is interesting to note that it was a biologist who provided the initial seed - see Roben M. May, 'Simple Mathematical Models with Very Complicated Dynamics' Nature 261 (10 June 1976): 459-467. For applications to human behaviour, see e.g., R.V. Jensen and R. Urban, 'Chaotic Price Behaviour in a Nonlinear Cobweb Model' Economic Letters 15 (1984): 235; Alfredo Medio, 'Advances in the Analysis of Econornic Dynarnic Systems: Introduction' Journal of Economic Behavior and Organization 8(3) (September 1987): 333-337 and accompanying articles; William A. Barnett, John Gewerke, and Karl Shell, (eds.), Economic Complexity: Chaos, Sunspots, Bubbles, and Nonlinearity, Proceedings of the Fourth International Symposium in Econornic Theory and Econometrics (Cambridge: Cambridge University Press, 1989); Hans-Walter Lorenz, Nonlinear Dynamical Economics and Chaotic Motion, Lecture Notes in Econornics and Mathematical Systems, Vol. 334 (Berlin: Springer Verlag, 1989); William J. Baumol and Jess Benhabib, 'Chaos: Significance, Mechanism, and Econornic Applications' Journal of Economic Perspectives 3(1) (Winter 1989): 77-105; Ronald A. Reiner, 'The 93

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to be analysed non-linear aspects are likely to be present, and it is of the essence of Homo biologicus that hierarchical elements permeate its nature and behaviour. Finally, and perhaps most fundamentally, economic analysis is of an inappropriate character. Economics is primarily concerned with quantitative changes: how much the quantity of butter demanded varies with changes in the margarine price, for example. Qualitative changes must stay within the bounds of the existing model (e.g., demand for butter and bread price) or the model and assumptions of actors' behaviour must be changed completely (the demand for money and the interest rate). The modelling of Homo biologicus requires, in contrast, techniques that are fundamentally informational in character, and only secondarily quantitative. With respect to panic on the stock exchange, for example, this means that a functional assessment of the necessary factors for an individual to panic must precede the proximate specification of how many shares he or she sells. Given the requirements for an adequate modeHing of Homo biologicus it seems apparent that an information-processing approach would be the appropriate path. A possible design for the model would be in two sections: one concerned with function (behaviour), and the other with its psychological mechanisms (cognitive programs and Darwinian algorithms, and, if appropriate, lower layers of the function/mechanism hierarchy). This would echo the important distinction between substantive and procedural rationality developed by Simon, who perceived behaviour as being: substantively rational when it is appropriate to the achievement of given goals within the Iimits imposed by given conditions and constraints. . .. The rationality of behaviour depends upon the actor in only a single respect - his goals. Given these goals, the rational behaviour is determined entirely by the characteristics of the environment in which it tak:es place. 94

Origin of Predictable Dynamic Behavior' Journal of Economic Behavior and Organization 12(2) (October 1989): 233-257. 94 Herbert A. Simon, 'From Substantive to Procedural Rationality' in Spiro J. Latsis (ed.), Method and Appraisal in Economics, pp. 129-148 (Cambridge: Cambridge University Press, 1976), p. 131 [hereafter Simon, 'Substantive to Procedural Rationality']. See also Herbert A. Simon, 'Rationality in Psychology and Economics' Journal of Business 59(4:2) (October 1986): S209-224 {reprinted in Robin M. Hogarth and Melvin W. Reder (eds.) Rational Choice: The Contrast Between Economics and Psychology (Chicago: University of Chicago Press, 1988), pp. 25-40}; James G. March, 'Bounded Rationality, Ambiguity, and the Engineering of Choice' Bell Journal of

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lf the words rational and rationality are interpreted as appropriate and appropriateness, then this represents the "situational detenninism" approach advanced above as being suitable for the analysis of behaviour. Simon's contrasting perspective on rationality is defined in terms of mechanisms: "behaviour is procedurally rational when it is the outcome of appropriate deliberation. Its procedural rationality depends upon the process that generated it". 95 That the words "deliberation" and "rationality" are used here in special senses is made clear in the following specification of procedural rationality, which captures the heuristic character of cognitive programs, and also makes clear their existence in other organisms: lf we take into account the limitations of knowledge and computing power of the choosing organism, then we may find it incapable of making objectively optimal choices. If, however, it uses methods of choice that are as effective as its decisionmaking and problem-solving means permit, we may speak of procedural or bounded rationality, that is, behavior that is adaptive within the constraints imposed both by the extemal situation and by the capacities of the decision-maker.96

Substantive and procedural rationality are normally regarded as competing concepts, but it is entirely possible to view them as being complementary, each associated with appropriate information-processing approaches. At the behavioural mechanism Ievel, an appropriate methodology would appear to be the use of evolutionary psychology to specify computer representations of an individual's cognitive programs. Using a hierarchical approach, the initial specification of a complex cognitive program such as that for trade could be in the form of simple decision rules: given x and y, and the absence of z, engage in social exchange; otherwise do nothing. As a computational theory is developed for the process, and the model is compared to observed behaviour, the necessary subsidiary cognitive processes could be allocated 'black boxes'. As these Darwinian algorithms are identified, such as

Economics 9(2) (Autumn 1978): 587-608 {reprinted in James G. March, 'Bounded Rationality, Ambiguity, and the Engineering of Choice' in David E. Bell, Howard Raiffa, and Amos Tversky (eds.), Decision Making: Descriptive, Normative, and Prescriptive lnteractions, pp. 33-57 (Cambridge: Cambridge University Press, 1988) }, esp. pp. {3842}. 95

Simon, 'Substantive to Procedural Rationality', p. 131.

Herbert A. Simon, 'Human Nature in Politics: The Dialogue of Psychology with Political Science' American Political Science Review 79(2) (June 1985): 293-304, p. 294 [emphasis in the original]. 96

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that which detects cheaters, these too can be specified in terms of their decision rules. If necessary the process may be applied again to the constitutional elements of these Darwinian algorithms, the next Ievel in the hierarchy. 97 This process could bear many similarities to the development of computer software, and as in programing some elements will be more "domain specific" than others, while certain structures will be like subroutines and may be used by a nurober of different cognitive programs. In one of the many facets of the reciprocal influences between nature, and our modelling of it, it appears likely that the use of selection-based principles will prove the most successful method of developing computer programs in general, and models of human psychology and behaviour in particular.98 Another facet of this interrelationship parallels the argument developed in chapter IV for the inadequacy of domain specific cognitive processes: Since 1970 the Deliberative Thinking paradigm has dominated Artificial Intelligence (Al) research. lts main thesis is that intelligent tasks can be implemented by a reasoning process operating on a symbolic internal model. Emphasis is put on explicit lcnowledge, rational choice, and problern solving. This approach has proved successful in knowledge-based task areas such as expert Ievel reasoning. However, only poor results have been obtained in its application to research on autonomous agents.99

97 The design of such "autonomous agents" has been an active field in Artificial Intelligence research; for a review see Pattie Maes, (ed.), Designing Autonomaus Agents: Theory and Practice from Biology to Engineering and Back, Special Issue of Robotics and Autonomous Systems, 6(1-2) (1990) (Cambridge, MA: MIT Press, 1990). For a discussion of hierarchies in the context of the choice of behaviour, see Toby Tyrrell, 'The Use of Hierarchies for Action Selection' Adaptive Behavior 1(4) (1993): 387-420. Many of the cognitive programs are likely to be instantiated as heuristics, rules of thumb that provide reasonable responses to a wide range of situations. For early discussions of the appropriateness of this technique, see Douglas B. Lenat, 'The Nature of Heuristics' Artificial Intelligence 19 (1982): 189-249; Douglas B. Lenat, 'Computer Software for Intelligent Systems' Scientific American 251(3) (September 1982): 189-249. 98 The classic description of the principles of "genetic programming" is John H. Holland, Adaptation in Natural and Artificial Systems: An Introductory Analysis with Applications to Biology, Control, and Artificiallntelligence, [1975] Ist MIT Press ed., Complex Adaptive Systems Series (Cambridge, MA: MIT Press, 1992). For a recent demonstration of their power and flexibility, see John R. Koza, Genetic Programming: On the Programming of Computers by Means of Natural Selection, Complex Adaptive Systems Series (Cambridge, MA: MIT Press, 1993), esp. pp. 619-642. 99 Pattie Maes, 'Guest Editorial: Designing Autonomous Agents' in Pattie Maes (ed.), Designing Autonomaus Agents: Theory and Practice from Biology to Engineering and

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Having appreciated the limitations of domain-general rational-choice approaches, artificial intelligence researchers are developing techniques which closely model the domain-specific, modular, and context dependent cognitive processes that humans possess. 100 It is an attraction of these new developments that a sharp distinction between the description of cognitive mechanisms and the modelling of behaviour substantive and procedural rationality- may be overcome through "emergent functionality", where: the functionality of an agent is viewed as an emergent property of the intensive interaction of the system with its dynamic environment. The specification of the behavior of the agent does not explain the functionality that is displayed when the agent is operating. Instead, the functionality to a !arge degree depends on the static and dynamic properties of the environment. The environment is not only taken into

Back, pp. 1-2, Special Issue of Robotics and Autonomous Systems, 6(1-2) (1990) (Cambridge, MA: MIT Press, 1990), p. 1. 100 A fundamental princip1e underlying this "nouvelle AI" is the rejection of the "symbol system hypothesis", that "the central system, or reasoning engine, operates in a domain independent way on the symbols" (Rodney A. Brooks, 'Elephants Don't Play Chess' in Pattie Maes (ed.), Designing Autonomaus Agents: Theory and Practice from Biology to Engineering and Back, pp. 3-15, Special Issue of Robotics and Autonomous Systems, 6(1-2) (1990) (Cambridge, MA: MIT Press, 1990), p. 4). For one general approach, the "situated automata'" model, see Leslie Pack Kaelbling and Stanley J. Rosenschein, 'Action and Planning in Embedded Agents' in Pattie Maes (ed.), Designing Autonomaus Agents: Theory and Practice from Biology to Engineering and Back, pp. 35-48, Special Issue of Robotics and Autonomous Systems, 6(1-2) (1990) (Cambridge, MA: MIT Press, 1990). A promising computational methodology isthat of an "evolution program", which is "a genetic algorithm enhanced by problem-specific knowledge" (Zbigniew Michalewicz, 'A Hierarchy of Evolution Programs: An Experimental Study' Evolutionary Computation 1(1) (1993): 51-76, p. 51). For explicitly biological prespectives, see Tracy L. Anderson and Max Donath, 'Anima! Behavior as a Paradigm for Developing Robot Autonomy' in Pattie Maes (ed.), Designing Autonomaus Agents: Theory and Practicefrom Biology to Engineering and Back, pp. 145-168, Special Issue of Robotics and Autonomous Systems, 6(1-2) (1990) (Cambridge, MA: MIT Press, 1990); Randall D. Beer, Hillel J. Chiel, and Leon S. Sterling, 'A Biological Perspective on Autonomous Agent Design' in Pattie Maes (ed.), Designing Autonomaus Agents: Theory and Practice from Biology to Engineering and Back, pp. 169-186, Special Issue of Robotics and Autonomous Systems, 6(1-2) (1990) (Cambridge, MA: MIT Press, 1990).

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account dynamically, but its characteristics are exploited to serve the functioning of the system. 101

This methodology is clearly weil suited to the modelling of behaviour proposed for Homo biologicus. lt is the combination of domain-specific cognitive programs with the particular situation that an individual finds him- or her-self in that determine behaviour. The analysis of the interactions of autonomous agents with each other, and with their "non-social" e~vironments, has also been an active field of reseach, often termed "artificial life" .102 By replicating the computer model of Homo biologicus as often as necessary for the problern at hand, and through the specification of intemal 'preferences', in combination with human and non-human extemal 'constraints', different forms of individual and group-related behaviour could be modelled. An illustration of the power of such an approach is the analysis of the effects of the behaviour of competing actors who form predictions about the future state of the world, where the aggregate result could not be deduced from knowledge of the individual characteristics alone. 103

Pattie Maes, 'Situated Agents Can have Goals' in Pattie Maes (ed.), Designing Autonomaus Agents: Theory and Practice from Biology to Engineering and Back, pp. 49-70, Special Issue of Robotics and Autonomous Systems, 6(1-2) (1990) (Cambridge, MA: MIT Press, 1990), p. 50. 101

102 See generally Christopher G. Langton, ed., Artificial Life, Santa Fe Institute Studies in the Seiences of Complexity, Vol. 6 (Reading, MA: Addison Wesley, 1989); Christopher G. Langton, ed., Artificial Life 1/, Santa Fe Institute Studies in the Seiences of Complexity, Vol. 10 (Reading, MA: Addison Wesley, 1992); Steven Levy, Artificial Life: The Questfora New Creation (New York: Pantheon Books, 1992), esp. pp. 233348; Stephanie Forrest, (ed.), Emergent Computation: Self-Organizing, Collective, and Cooperative Phenomena in Naturaland Artificial Computing Networks, Special Issue of Physica D 42 (1990) (Cambridge, MA: MIT Press, 1991). A very productive methodology with a wide range of applications is the use of "cellular automata", of which the orginal computer game of Life is the classic example; see e.g., Howard Gutowitz, (ed.), Cellular Automata: Theory and Experiment, Special Issue of Physica D 45 (1990) (Cambridge, MA: MIT Press, 1991). 103 Jeffrey 0. Kephart, Tad Hogg, and Bemardo A. Huberman, 'Collective Behavior ofPredictive Agents' in Stephanie Forrest (ed.), Emergent Computation: Self-Organizing, Collective, and Cooperative Phenomena in Natural and Artificial Computing Networks, Special Issue ofPhysica D 42 (1990) (Cambridge, MA: MIT Press, 1991), esp. pp. 4850. See also John J. Grefenstette, 'The Evolution of Strategies for Multiagent Environments' Adaptive Behavior 1(1) (1992): 65-90.

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Through such an artificial Iife model it should thus be possible to simulate the behaviour not only of individuals, but also of supra-individual entities, such as families, firms, or states, while at the same time preserving the character of the constituent individuals. Suppose, for example, that the phrase "our fatherland is threatened by cheating foreigners" is shown to trigger obedience and self-sacrifice, 104 whereas "the economy is threatened by large increases in wages and salaries" does not. In appropriate circumstances the former cue, but not the latter, should then initiate Homo biologicus's cognitive program for obedience, engendering the agentic shift, manifesting itself in obedient behaviour. Through the use of such modelling techniques it thus appears possible to overcome the limitations of economic analysis by introducing a hierarchical structure, dynamics, non-linearity, and an information-handling character. At the sametime the central techniques of economics - such as marginal analysis, explicit and implicit prices, markets, and equilibria - should be able to be incorporated into such computer-based simulations. 105

104 For discussions of the impact of verbal and non-verbal comrnunication by political Ieaders see e.g., Roger D. Masters, The Nature of Politics (New Haven, CT: Yale University Press, 1989), esp. pp. 52-66; Denis G. Sullivan and Roger D. Masters, "'Happy Warriors": Leader' s Facial Display, Viewers' Emotions, and Political Support' American Journal of Political Science 32(2) (1988): 345-368, esp. p. 362; A. Michael Warnecke, Roger D. Masters, and Guido Kempter, 'The Roots of Nationalism: Nonverbal Behavior and Xenophobia' Ethology and Sociobiology 13(4) (July 1992): 267-282, esp. 276-279. 105 The suggestion that the modeHing of cognitive processes and the simulation of individual behaviour could be the appropriate general methodological route should not be interpreted as implying the absence of a roJe for analytical approaches. Formal analysis as exemplified by neoclassical economics could be expected to remain the most elegant method of approaching many specific problems, but would seem incapable of providing an adequate mode of analysis for all behaviour, as discussed above. The creation of a theoretical and methodological framework which can be implemented in practical research applied to specific problems is a primary objective of the Homo biologicus approach, and the achievement of this goal is clearly assisted by maintaining close links to the well-established disciplines such as neoclassical economics. The principles of sirnational determinism and maximisation subject to constraints, which have already Iead to productive links between biology, psychology, and economics (see e.g., the contributions in John E.R. Staddon, (ed.), Limits to Action: The Allocation of Individual Behavior (New York, NY: Academic Press, 1980)), remain the foundations for the modelling of behaviour in this proposed methodology; it is their instantiation that differs. The failures of many criticisms to offer such an operational alternative is a

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An initial disadvantage would appear to be that discriminating between hypotheses could be more difficult than with conventional models, due to the Iack of established statistical tests. Although this may prove to be a difficulty, simulations have the advantage of affering a very direct link between a model and reality, so that if the problern is sufficiently accurately specified, then the success or failure of a particular simulation will often be self-evident. An associated attraction is that computer models are generally easier to camprehend than abstract analyses, easing the linking of diverse disciplines. Should it be possible to create successful computer-based representations of Homo biologicus, then that would greatly ease the linking of the different disciplines within the human sciences, and a vision appears of a disciplinary hierarchy paralleling the function/mechanism hierarchy. The different social and behavioural sciences could investigate the diverse forms of individual and supraindividual behaviour such as social exchange, rape, family altruism, or war, making specific simulations in the general artificial Iife computer framework. They would thus respond to research from the cognitive disciplines, and would in turn supply information about the fit between model and observed behaviour that could greatly aid the specification of psychological processes. In psychological research it should also be possible to retain areas of disciplinary specialisation within the common generat framework. Thus evolutionary psychologists could continue to unravel the cognitive structures that arose in their environments of evolutionary adaptedness, and to provide a common evolutionary methodology for psychological research. At the same time specialists in particular fields, such as vision or conformity, could combine their knowledge with the common methodology, and map out the characteristics of the specific cognitive mechanisms involved. These specifications would then be included in the heuristic 'psychology' of Homo biologicus, and be criticised by behavioural researchers, with the result that the general research program could proceed in a self-correcting way.

primary reason for the continuing dominance of Homo oeconomicus: Reiner comments, for example, in the light of attacks on the rationality assumption, that "however plausible these arguments might be, ultimately they must be set aside by someone desiring a theoretical understanding of behaviour, unless they Iead to another modeHing structure whose analytical ability can be explored and compared with existing optimization theory" Ronald A. Reiner, 'The Origin of Predictable Behavior' American Economic Review 73(4) (September 1983): 560-595, p. 560.

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Parallel to the disciplines specialising in either behaviour or cognition are those that investigate both, such as law or medicine, and those which compare different slices through space and time, such as anthropology, history, and paleontology. These too could be linked to the other disciplines of the human sciences by the common evolutionary framework and Homo biologicus, which they could draw on to model and test their hypotheses, and add to or change as a result of their particular research. Finally, biology in general, and evolutionary theory in particular, could provide a general framework within which behaviour, cognition, and all the other Ievels of function and mechanism could be analysed and interpreted, and which could link the study of humans horizontally to the study of other species, and vertically to the other sciences. The normal functioning of these traits could provide the basis for understanding abnormalities, and phenomena such as senescence or parasitism which are harmful to humans, creating the discipline of "Darwinian medicine" . 106 Should this vision be realised, the scientific study of humans could share the same methodology and theory as the study of, for example, chimpanzees, and both would be specialisations of the life sciences and associated with the physical sciences. It may be that it is this departure from a human-centred perspective which is finally most vital for the linkage of the human sciences, just as the realisation that the earth is not the centre of the solar system was necessary for a science of astronomy; the inclusion of Homo sapiens as one species among many was necessary to the theory of evolution; and the appreciation of the inadequacy of human perceptions of time, space, and matter was necessary for the theories of relativity and quantum mechanics. Such a rejection of the special status of humans, and the recognition of the study of human cognition and behaviour as specialised sub-disciplines within the general framework of biology, must first overcome deep-seated emotional and philosophical prejudices. These are discussed in the next section.

106 This new discipline is an outstanding example of the potentiality of grounding the human sciences on evoluionary theory; for a review see George C. Williams and Randolph M. Nesse, 'The Dawn of Darwinian Medicine' Quarterly Review of Biology 66(1) (March 1991): 1-22.

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4. Evolutionary Research and Human Characteristics a) Opposition to Evolutionary Research A principal implication of evolutionary theory is that we, mortal humans, exist because of, and evolved as mechanisms for, them, potentially immortal genetic replicators. As Alexander expresses it: When we are told about genes, we tend to see them as alien manipulators, the very phenomena we are likely to be evolved to resist most intensively in our social behavior. It is perhaps understandable that we have a kind of xenophobia not only toward the genes, and ideas that such unebanging objects could somehow underlie our behaviour, but also toward anyone who may argue that he has some _special insight into our interests. 107

Although evolutionary explanations of physical characteristics no Ionger excite widespread opposition, evolutionary interpretations of "mental organs" and behaviour can be subject to severe attacks. The ostensible reason for such antagonism is often a supposed link to previous biological interpretations of human characteristics, which: provided an important basis for the enactment of sterilization laws and restrictive immigration laws by the United States between 1910 and 1930 and also for the eugenics policies which led to the establishment of gas chambers in Nazi Germany. 108

107 Alexander, Moral Systems, p. 39. Elsewhere Alexander terms this phenomenon "genophobia"; see Richard D. Alexander, 'Genes, Consciousness, and Behavior Theory' in S. Koch and D.E. Leary (eds.), A Century of Psychology as Science, pp. 783-802 (New York: McGraw Hili, 1985), p. 790 [hereafter Alexander, 'Genes, Consciousness, and Behavior Theory']. In a similar discussion Daly and Wilson have called such anitudes "biophobia" (Daly and Wilson, Homicide, p. 154), and that is the expression used here.

108 Elizabeth Allen et al. 'Against "Sociobiology"' New York Review of Books (13 November 1975): 43-44, p. 43 [hereafter Allen et al. 'Against "Sociobiology"']. Every time I enter my office in Berlin I am reminded by a bronze plaque of the reprehensible actions associated with biology in the past; the following discussion should not be interpreted as in any way condoning the politically motivated abuse of biology, such as the eugenics movement under the Nazis. For an account of such horrors see, e.g., Bentley Glass 'The Roots of Nazi Eugenics' Quanerly Review of Biology 64(2) (June 1989): 175-180; Heidrun Kaupen-Haas (ed.), Der Griffnach der Bevölkerung: Aktualität und Kontinuität nazistischer Bevölkerungspolitik, Schriften der Hamburger Stiftung für

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While the justification for such antagonism is often the alleged links to the reprehensible policies of the past, the underlying reasons appear to be the rejection of the 'unattractive' conclusions of evolutionary research. This is, in essence, a modernised version of the argument of the bishop's wife, who, on hearing ofDarwin's theory, exclaimed: "Descended from apes! My dear, Iet us hope that this is not so, but if it is, that it not become known"! 09 Wilson has examined the logical process underlying this process, terming it: The Fallacy of the Political Consequent. This is the assumption that political belief systems can be mapped one-on-one onto biological or psychological generalizations. . . . The cause of the Fallacy of the Political Consequent is the failure to appreciate adequately that scientific theories and political ideas are both complex and tenuously linked, and that political ideas are shaped in good part by personal judgements lying outside the domain of scientific evaluation. 110

An example is a recent review of an edited volume which criticises several of the findings presented in the previous chapter, commenting, for example, that: Are we all just kidding ourselves about our humanity, or are sociobiologists replacing psychology with evolutionary speculation? ... . . . Buss cites seven studies to show that men seek female mates who are physically attractive; period! So much for the women's movement. 111

The emotionalism is apparent from the style, while the opposition to Buss's (misrepresented) studies is not based on the research itself, but on the results which arenot congruent with 'desirable' human behaviour. This conclusion is reinforced by Scarr' s handling of the investigations of rape by Thomhill and

Sozialgeschichte des 20. Jahrhunderts, Vol. 1 (Nördlingen: Franz Greno, 1986); Änne Bäumer, NS-Biologie (Stuttgart: S. Hirze1, 1990), esp. pp. 113-147. 109 Quoted in Robert A. Foley, 'Putting People into Perspective: An lntroduction to Community Evolution and Eco1ogy' in Robert Fo1ey (ed.), Hominid Evolution and Community Ecology: Prehistoric Human Adaptation in Biological Perspective, pp. 1-23, Studies in Archaeo1ogy Series (London: Acadernic Press, 1984), p. 1. 110 Edward 0 . Wilson, 'Acadernic Vigilantism and the Political Significance of Sociobio1ogy' Bioscience 26 (March 1976): 183, 187-190 {reprinted in James H. Hunt (ed.) Selected Readings in Sociobiology, New York, NY: McGraw-Hill 1980, p. 424-432}, p. {432} [hereafter Wilson, 'Acadernic Vigilantism'].

111 Sandra Scarr, 'Sociobiology: The Psychology of Sex, Violence, and Oppression?' Contemporary Psychology 34(5) (May 1989): 440-443, p. 442 [hereafter Scarr, 'Psychology of Sex, Violence, and Oppression?']. The volume reviewed is Charles Crawford, Martin Srnith, and Dennis Krebs (eds.), Sociobiology and Psychology: Ideas, Issues, and Applications (Hillsdale, NJ: Lawrence Erlbaum Associates, 1987).

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Thomhill, and infanticide by Daly and Wilson. Scarr objects to the rape study, because "rape, then, becomes an 'understandable', even logical strategy, not a revolting offence against women" .112 With respect to infanticide research, while recognising that it involves "mothers who murder their infants", she comments that "one may object to the Iack of affect or cognate sensibility attributed to the actors in these very personal dramas". 113 lt should be clear that neither comment is directed at the research per se, and that Scarr's principal concem is that the behaviour of rapists (men) becomes understandable, while not enough understanding is shown to those who kill their children (women). Scarr' s concem with sexual differences is a recurring theme in criticisms of evolutionary research into human characteristics, for example: Sociobiology cannot be divorced from its sexism. Not only are the postulated human universals sexist, but the asserted mode of their propagation in evolution is sexist as well.114

This allegation of endernic sexism has been rejected in a study exarnining evolutionary research from a ferninist perspective, 115 although some may regard as sexist the apparently Straightforward hypothesis that "men and women seem to be different because they are different". 116

112 Scarr, 'Psychology of Sex, Violence, and Oppression?', p. 441. 113 lbid., p. 442. 114 Joseph Alper, Jon Beckwith, and Lawrence G. Miller 'Sociobiology is a Political Issue' in Artbur L. Caplan (ed.), The Sociobiology Debate: Readings on Ethical and Scientific Jssues, pp. 476-488 (New York: Harper & Row, 1978), p. 485. The depths to which such writing may descend is illustrated by the attribution of the manifestly human characteristic of sexism to the abstractnature of evolutionary processes: "But deeper than the sexist biases in the sociobiologists' selection of the universal traits is the sexism that is inherent to the structure of the theory of sociobiology as it exists today. Sociobiology relies almost totally on Darwinian sexual selection as the mechanism for the evolutionary development of characteristics" (ibid., p. 484). 115 "Evolutionary biology, and its offspring, sociobiology, ... are not inherently

sexist The proportion of 'sexists' among their proponents is probably no greater than the proportion among scientists generally." Sarah Blaffer Hrdy, The Woman that Never Evolved (Carnbridge, MA: Harvard University Press, 1981), p. 14 [hereafter Hrdy, Woman that Never Evolved]. 116 Symons, 'Darwinian Anthropology', p. 143.

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b) Consequences of "Biophobia"

Perhaps the least dangerous result of allowing evolutionary research and normative convictions to intertwine is simply poor quality work: As soon as they come anywhere near ethology and sociobiology, their perception becomes clouded by so much indignation that they fail to discriminate between good and bad ideas . . . Sloppy scholarship and bad argument, even when casually introduced, seriously devalue the whole enterprise. 117

Some opposition has been clearly directed at inhibiting evolutionary research into human characteristics, through, for example, personal attacks, the discouragement of potential scholars, and the prevention of conferences and lectures. 118 Perhaps more dangerous, because more subtle and pernicious, are the indirect effects of antagonism and resistance. Bannister argues, for example, that the perceived dangers of "Social Darwinism" played an important roJe in swinging American social science away from biological theoretical structures: After the war, of course, serious thinkers almost universely [sie] abandoned the evolutionary framework entirely in favour of cultural, ecological, or behavioristic models. While it is too much to claim that attacks on social Darwinism alone

P. Patrick G. Bateson, 'Sociobiology: The Debate Continues' New Seienrist 105 (24 January 1985): 58-59, p. 58. Readers may be amused to note that this was written as the 'defence' in a comparative review of Rose, l..ewontin, and Kamin, Not in our Genes. Fora full-blooded criticism see Richard Dawldns's parallel criticism, pp. 59-60. In a later work one of the authors explicitly states that "it is a sign of the Marxist dialectic with which we align ourselves that scientific and political questions are inextricably interconnected - dialectically related" (Richard Levins and Richard C. Lewontin, The Dialectical Biologist (Cambridge, MA: Harvard University Press, 1985), p. viii [hereafter Levins and Lewontin, Dialectical Biologist]). 117

118 Wilson has termed such behaviour "academic vigilantism", which is "the judgement of a work of science according to whether it conforms to the political convictions of the judges, who are self-appointed. The sentence for scientists found guilty is to be given a Iabel and to be associated with past deeds that all decent persons will find repellent." Wilson, 'Acadernie Vigilantism', p. {424}. For an account of specific cases and a general review see Roger Pearson, Race, lntelligence and Bias in Academe (Washington, DC.: Scott-Townsend, 19.91) [hereafter Pearson, Bias in Academe]. See also Alexander, 'Future', p. 317.

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brought this major shift in American social science, its continuing roJe in sociological debate in the intelWar years suggests that it was a contributing factor. 119 A further indirect consequence is that the establishment of such a negative "myth of Social Darwinism" 120 may have contributed to the establishment of a competing belief in cultural malleability. It has been said of the latter that: [this] myth .fills a need for social scientists and commentators. It seems to demoostrate that our social natures are pure cultural artifacts, as arbitrary as the name of the rose, and we can therefore create any world we want, simply by changing our "socialization practices."121

An example is Wolfgang's "monodisciplinary perspective", which essentially rejects the importance of evolutionary and psychological perspectives: Biological needs and psychological drives may be declared uniforrnly distributed and hence of no utility in explaining one form of behavior relative to another. They may be seen as differential endowments of personalities that help to assign, for example, a labe! of mental incapacity to a group of individuals, some of whom have also violated the criminal codes. But neither the biology of many biographies, nor the psychology of many personalities helps to explain the oveiWhelming involvement of men over women, slums over suburbs, youth over age, urban over rural life. 122 In sharp contrast to Wolfgang's sociological approach is Daly and Wilson's path-breaking use of evolutionary psychology to investigate homicide and related behaviour, some aspects of which were reported in the previous chapter. The picture that emerges from their research is of an extremely complex set of influences on quite distinct forms of behaviour, which do not form a simple coherent category of "deviance" or "family violence", Iet alone lend themselves to being solved by measures such as forced dispersal. 123

119 Robert C. Bannister, Social Darwinism: Science and Myth in Anglo-American Social Thought (Philadelphia: Temple University Press, 1979), p. 11 [emphasis in the original; hereafter Bannister, Social Darwinism].

120 Bannister, Social Darwinism, p. 10. See also Greta Jones, Social Darwinism and English Thought: The Interaction between Biological and Social Theory (Brighton: Harvester Press, 1980), esp. 160-195. 121

Daly and Wilson, Homicide, p. 153 [emphasis in original].

Marvin E. Wolfgang, 'Family Violence and Criminal Behavior' in Robert L. Sadoff (ed.), Violence and Responsibility: The Individual, the Family and Society, pp. 87-103 (New York: Spectrum, 1978), p. 87. 122

123 "Dispersion can be done in many ways and does not necessarily imply massive population shifts, although urban renewal, slum clearance, and housing projects suggest feasible methods" Wolfgang, ibid., p. 100.

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It is one of the many ironies of this Iiterature that, although the academic left has launched some of the most polemical assaults on evolutionary research, it is a leftist intellectual who has perhaps most vividly shown the dangers of the myth of cultural malleability:

One can easily see why reformers and revolutionaries should become radical environmentalists. . . But a deeper Iook will show that the concept of the "empty organism," plastic and unstructured, apart from being false, also serves naturally as the support for the most reactionary social doctrines. If people are, in fact, malleable and plastic beings with no essential psychological nature, then why should they not be controlled and coerced by those who claim authority, special knowledge, and a unique insight into what is best for those less enlightened? . . . The principle that human nature, in its psychological aspects, is nothing more than a product of history and given social relations removes all barriers to coercion and manipulation by the powerful. This too, I think, may be a reason for its appeal to intellectual ideologists, of whatever political persuasion. 124 Perhaps the most dangeraus result of allowing an ideological commitment to interfere with scientific research is illustrated by Mead' s Samoan investigations, where: admittedly looking for light on the subject of sex differences, I found three tribes all conveniently within a hundred mile area. In one, both men and women act as we expect women to act - in a mild parental responsive way; in the second, both act as we expect men to act - in a fierce initiating fashion; and in the third, the men act according to our stereotype for women - are catty, wear curls and go shopping, while women are energetic, managerial, unadorned partners. m Detailed research has since shown that many of Mead's results were incorrect and based on inaccuracies or misrepresentations; actual behaviour in each of the societies showed typical sex differences. 126 Politically acceptable research

124 Chomsky, Reflections on Language, p. 132. In a revealing aside, Levins and Lewontin record that "Noam Chomsky once remarked to one of us, who accused him in a conversation of being insufficiently dialectical, that he despised the term and that in its bestsense dialectics was only another way of saying 'thinking correctly'" (Levins and Lewontin, Dialectical Biologist, p. vii).

Margaret Mead, Sex and Temperament in Three Primitive Societies [1935] (New York: William Morrow, 1963), preface to the 1950 edition. 126 This is particularly associated with the detailed and vigorous criticism of Mead's work on Samoa by Freeman which unleashed a major debate within anthropology; see Derek Freeman, Margaret Mead and Samoa: The Making and UnrruJking of an Anthropological Myth (Cambridge, MA: Harvard University Press, 1983). See e.g., 125

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may assume its own momentum, however, and while Mead's representation has been severely damaged among anthropologists, her writings and ideas continue to influence millions. 127

c) Diversity and Discrimination Associated with concerns about evolutionary research revealing Iimits to cultural malleability are worries that it will demoostrate a genetic component to traits that differ among identifiable groups, such as those based on sex or race. 128 Here, again, an artificial distinction is drawn between the physical and mental characteristics, as it is generally accepted that differences in physical traits such as stature, skin, or the sexual organs have a significant genetic Evolutionary investigations of sytematic differences in component. 129 characteristics such as mathematical ability, spatial orientation, intelligence test scores, or behavioural traits, are in contrast extremely controversial. 130

Lowell D. Holmes, 'Margaret Mead's Samoa: Views and Reviews' Quarterly Review of Biology 58 (December 1983): 530-544; Richard Feinberg, 'Margaret Mead and Samoa: Coming of Age in Fact and Fiction' American Anthropologist 90 (1988): 660-663). 127 Mead was an accomplished publicist: in a survey of the most important introductory texts in psychology, anthropology, and sociology, Minderhaut found that Mead was the most frequently cited anthropologist in 25 of 61 psychology texts (David J. Minderhout, 'lntroductory Texts and Social Seiences Stereotypes' Anthropology Newsletter 27(3) (March 1986): 20, 13-15, table 3 p. 15 and tables 2 and 3 p. 20). Benedict was Mead's mentor (see e.g., Ruth Benedict, Patterns of Culture (Boston: Roughton Mifflin, 1934), and Mead and Benedict shared frrst place in the sociology ranking, each with references in 40 of the 51 sociology texts (ibid.). 128 As emphasised above, all traits result from the interaction of genetic replicators with their environment. Nobody disputes the importance of the environment, but extreme environmentalists dispute the importance of the genetic heritage.

See generally Wesley M. Brown, 'Polymorphism in Mitochondrial DNA of Rumans as Revealed by Restrietion Endonuclease Analysis' Proceedings ofthe National Academy of Seiences of the United States of America 77(6) (June 1980): 3605-3609; James C. King, The Biology of Race (Berkeley, CA: University of Califomia Press, 1981) [hereafter King, Biology of Race]. That at least some of these differences were selected for in the environment of evolutionary adaptedness, and not merely the result of the effects of drift within non-interbreeding populations, is shown by the correlation of limb to body segment proportians with climatic variations as predicted by Bergmann' s and Allen's rules; see Stringer, 'Adaptation in the Pleistocene', pp. 67-71. 129

130 For hypothesised psychological differences see, e.g., Camilla Persson Benbow, 'Sex Differences in Mathematical Reasoning Ability in lntellectually Tatented

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The Ievel of controversy generated by these and similar debates is so high that it is appropriate to consider some of the general issues involved without examining specific hypotheses, as these are peripheral to the general methodology developed here. That the evolutionary process emerges through selection operating on variation among genetic replicators is beyond dispute, forming the core of evolutionary theory. A central thesis of this work is that psychological characteristics and the behaviour they permit are formed by selection in exactly the same manner as physical traits. The clear implication is that diversity is to be expected with respect to mental organs as with physical organs, and can similarly be divided into two forms. Functional variations involved differential selection of vehicles in the environment of evolutionary adaptedness, and resulted in, for example, the sexual differences in reproductive strategy examined in the previous chapter. lt is such functional variation that forms the subject of dissension, and about which positions are sharply divided. Essentially uncontroversial, in contrast, are the subfunctional variations that differentiate any two individuals: Below the Ievel of functional architecture, however, there is a sea of uncoordinated protein variation. Given the intricate design complexity of the nervous system (as weil as of other organ systems), this protein variation gives rise to a wealth of quantitative variation in nearly every manifest feature of the psyche: Tastes, reflexes, perceptual abilities, talents, deficits, thresholds of activation, motor skills, verbal skills, activity Ievel, abilities to remernher different kinds of things, and so on- all vary from individual to individual in a quantitative way. 131

Preadolescents: Their Nature, Effects, and Possible Causes' Behavioral and Brain Seiences 11(2) (June 1988): 169-232; lrwin Silverman and Marion Eals, 'Sex Differences in Spatial Abilities: Evolutionary Theory and Data' in Jerome H. Barkow, Leda Cosmides, and John Tooby (eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, pp. 495-532 (Oxford: Oxford University Press, 1992); Arthur R. Jensen, 'The Nature of the Black-White Difference on Various Psychometrie Tests: Spearman's Hypothesis' Behavioral and Brain Seiences 8(2) (1985): 193-263, p. 194. For hypothesised behavioural and morphological differences see e.g., Richard Lyon, 'New Evidence on Brain Size and Intelligence: A Comment on Rushton and Cain and Vanderwolf' Personality and Individual Differences 11(8) (1990): 795-797; J. Philippe Rushton and Anthony F. Bogaert, 'Race Differences in Sexual Behavior: Testing an Evolutionary Hypothesis' Journal of Research in Personality 21 (1987): 529-551. See generally Pearson, Bias in Academe, esp. pp. 216-243. 131

Tooby and Cosmides, 'Universality and Uniqueness', p. 49.

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Despite what is implied by many criticisms of evolutionary research into human characteristics, functional and subfunctional variations are objectively ascertainable facts - they are not somehow brought into existence by evolutionary theory. The fundamental problern is thus whether such differences should be the subject of research, or whether their identification and investigation should be lirnited or prohibited. It may be that some organisations and societies decide to Iimit acadernic freedom, on the basis that the possible dangers of the research outweigh the likely benefits involved, just as other forms of scientific research or technological developments are subject to controls. It would seem reasonable, however, that the imposition of such restrictions be subject to open debate, rather than resulting from a generalised prohibition of evolutionary research into human characteristics. The issue that appears to lie at the heart of the concem about diversity is discrirnination: if characteristics of particular groups could be associated with a genetic foundation, then that could justify unequal treatment. It has been concluded above that variation in behavioural traits, and the cognitive processes that underlie them, exists, and that such diversity is due to differences in genetic inheritance, developmental trajectories, and specific situations. The use of perceived or imagined differences as the basis for differentiated handling of individuals or groups is a fact of life: one applicant among many is offered a job or an university place; children are not permitted to vote; the blind are not allowed to drive cars. It should be clear that distinctions among individuals will always be drawn - it is a necessary concornitant to living in societies. The difficult issue is then discrirnination against groups, a practice which long predates evolutionary research. It is one of the great innovations of modern legal systems that most discrirnination on the basis of group membership is no Ionger permitted, and there is absolutely no reason why the continuation of evolutionary research into human characteristics should affect this commendable achievement. To the contrary, one of the major achievements one could wish from research resulting from Homo biologicus is that group behaviour such as racism, sexism, ethnocentrism or anti-Sernitism could be more completely understood, and hence more effectively counteracted. One suspects that finally the concem with diversity and discrirnination is another facet of the desire for environmental malleability discussed above. The argument that half of the numbers of students, professionals, politicians, and so on should be women and the other half men, or that ethnic groups should be proportionately represented in these fields, rests implicitly upon the presumption that these

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groupings are statistically identical with respect to desires and potentialities, and that the observed differences result from discrirnination. The approach developed here perrnits another perspective on human diversity, one that is more complex and richer. All the elements in the hierarchy of function and mechanisms are interpreted as having maxirnised the survival of genetic replicators in the environment of evolutionary adaptedness, and all current behaviour is interpreted as maxirnising net aggregate value, in an undefined space no Ionger tied to replicator survival. Hence the conventional dimensions along which human characteristics are measured and assessed (such as intelligence or income) are no Ionger perceived as objective unidimensional measuring rods, but rather subjective values associated with a specific culture. 132 Thus there can be no objective unidimensional measuring rods: each individual is maximising in his or her own 'private world' shaped by their particular genetic endowments, life history, and situation. Although statistically representative characteristics allow the specification of models based on Homo biologicus, each of the characteristics of every specific individual diverges from such typical values. An extemal observer can ascribe values to behaviour: as being, for example, advantageaus or disadvantageaus for the society, the farnily, or the individual concemed. These are, however, subjective rankings, unrelated to any intrinsic order among the individuals being compared. d) Determinism and Freedom

One of the most widespread criticisms of evolutionary interpretations of human characteristics is that they are deterrninist: Biological determinists ask, in essence, Why are individuals as they are? Why do they do what they do? And they answer that human lives and actions are inevitable consequences of the biochemical properties of the cells that make up the individual; and these characteristics are in turn uniquely determined by the constituents of the genes possessed by each individual. Ultimately, all human behaviour - hence all human society - is govemed by a chain of determinants that run from the gene to the individual to the sum of the behaviors of all individuals. The determinists would have it, then, that human nature is fixed by our genes. 133

132

Fora sirnilar approach see King, Biology of Race, pp. 153-159.

Rose, Lewontin, and Kamin, Not in our Genes, p. 6. See also Allen et al. 'Against "Sociobiology"'; Stephen Jay Gould, Ever Since Darwin: Rejlections in 133

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Again the hierarchical relationship between mechanisms and function assists the understanding of the problem. The evolutionary perspective is both materialist and determinist with respect to mechanisms, 134 in that it assumes that the rnind and all its manifestations result from antecedent sufficient material causes. In an apparent paradox, however, the approach asserts free will with respect to the functional manifestation of these mechanisms, in the sense of "the apparent human ability to make choices that are not extemally determined". 135 Freedom of choice exists because behaviour is created by intemal psychological processes, as a result of the adaptive advantages these provided in the environment of evolutionary adaptedness. Extemal determination of acts may simplify the cognitive apparatus, as in the seasonal cues which determine the shedding of leaves by a deciduous tree, but are expected to result in less flexibility, in response to the particular situation and life history of an organism. The result of these intemal processes is to equip humans with cognitive programs that are deterministic with respect to their mechanisms, but provide free will, in that choices are made by the individual rather than imposed by the extemal environment. Although this may appear a little confusing, it is in essence sirnilar to the farniliar phenomenon that deterministic mechanisms intemal to birds provide them with the freedom to temporarily 'escape' the general law of gravity. 136 This form of escape from determinism is essentially the concept of freedom of choice from neoclassical econornics or game theory ,137 with the added

Natural History (New York: W.W. Norton, 1978), p. 238; Steven Rose, 'Pre-Copernican Sociobiology' New Scientist 80 (1978): 45-46; lsadore Nabi, 'Ethics of Genes' Nature 290 (19 March 1981): 183; Kitcher, Vaulting Ambition, p. 406-417. 134 "Determinism" is understood in the sense that "all acts, choices, and events are the inevitable consequence of antecedent sufficient causes" (Collins Dictionary s.v. "determinism"). Materialism is interpreted as "the doctrine that matter is the only reality and that the mind, the emotions etc. are merely functions of it" (ibid., s.v. "materialism"). 135

Collins Dictionary s.v. "free will".

"If you throw a dead bird into the air it will describe a graceful parabola, exactly as the physics books say it shou1d, then come to rest on the ground and stay there. It 136

behaves as a solid body of a particular mass and wind resistance ought to behave, But if you throw a live bird in the air it will not describe a parabola and come to rest on the ground. It will fly away, and may not come to rest on this side of the county boundary." Dawkins, Blind Watchmaker, p. 11. 137 This point has been strongly made by Alexander: "it is inaccurate to charge that the evolutionist's approach involves excessive determinism; on the contrary game theory

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provision that human variation rooted in genetic variability provides an absolute Iimit to the identification of individual characteristics. In this sense the life sciences have an accurate equivalent of Heisenberg's uncertainty principle, to replace the widely used misrepresentation that "the observer always interferes with the phenomenon under observation". 138 This is rather a shallow conception of "free will", however, as the principles of maximisation and situational determinism mean that an individual' s characteristics, together with "the logic of the situation", combine to create a "single exit". This may Iead to behaviour varying from that of the representative Homo biologicus, but it is statistically predictable through inclusion of appropriate error terms. This type of freedom applies in fact with equal validity to other organisms, although the complexity of their 'choice processes', and the extent of the domains to which they apply, will generally be less than for humans.139 The evolutionary approach reveals the possibility of a more profound form of freedom than this mechanical economic sense, and again a physical analogy - the epitome of a rational choice theory of behavior - has been prorninently incorporated into the analyses and predictions of these evolutionary biologists" Richard D. Alexander, 'Biology and Law' Ethology and Sociobiology 7(3/4) (1986): 167-173 {reprinted in Margaret Gruter and Roger D. Masters (eds.), Ostracism: A Social and Biological Phenomenon, pp. 19-25 (New York: Elsevier Science Publishing, 1986)}, p. 171 {23}. Seegenerally Patrick J. O'Sullivan, Economic Methodology and Freedom to Choose (London: Allen & Unwin, 1987), esp. pp. 78-90; Milton Friedman and Rose Friedman, Free to Choose (London: Secker & Warburg, 1980); Amartya K. Sen, 'Freedom of Choice: Concept and Content' European Economic Review 32(2-3) (March 1988): 269-294 [hereafter Sen, 'Freedom of Choice']. Douglas R. Hofstadter, Metamagical Themas: Questing for the Essence of Mind and Pattern (New York: Basic Books, 1985), p. 456. 138

lt is indeed to be hoped that the methods used to model Homo biologicus can generally be applied to investigations of other species. Symons has eloquently called for such an application of evolutionary psychology to non-human biology: "it is impossible to have a truly sophisticated science of grasshopper affairs in the absence of a science of the grasshopper mind (i.e., nervous system), but we can make a respectable start because grasshopper motor pattems and the environmental configurations that elicit these pattems are so simple and stereotyped that we can describe grasshopper affairs in terms of movement-environment regularities. Our hypotheses about grasshopper affairs in effect are approximate provisional hypotheses about neurophysiology: In essence we are using our descriptions of grasshopper movement pattems and eliciting environmental configurations as rough characterizations of underlying mechanisms" (Symons, 'Darwinian Anthropology' , pp. 134-135 [emphasis in the original]). 139

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may make arguments with respect to the the mental processes clearer. The view was advanced above (page 68) that an interpretation of Dawkins' "extended phenotype" was in terms of vehicles that maxirnise by using other organisms than their own as mechanisms. Thus one can conceive of a man confined to bis apartment, with a bacterially infected foot, in these trade and expropriation terms. The 'lower order' elements in the human's functionlmechanism hierarchy, such as the biochernistry of protein production, continue to work normally, but because of the 'expropriation' of the bacteria within the foot, 'higher-order' elements, such as walking, are impaired or prevented. All of the maxirnisation processes of the bacteria function as selected for in the environment of evolutionary adaptedness, leading to the maxirnisation of net aggregate value, which for bacteria probably closely approximates the maxirnisation of replicator survival. In contrast, the behaviour of the invalid, and the possibility of bis acting as a mechanism for the genet, kin-group, or group vehicles, has been severely constrained. That the logic of this 'physiological hijacking' could equally apply to a 'cognitive hijacking' has already been demonstrated for simpler organisms, in the example ofthe "brainworm" discussed above (page 115). lmagine, however, that instead of a foreign organism it is the individual hirnself that causes this 'cognitive hijacking' . The invalid would then be confined through internal conviction, rather than externally-imposed necessity, to bis apartment. He would then be refusing, through conscious decision, to exhibit traits that in the environment of evolutionary adaptedness maxirnised replicator survival, and which would normally have maxirnised in other spaces in the present. He may instead choose, like Proust, to close the curtains and write about people and the societies they form, or to lie in the bath and ponder the nature of the world like a Greek philosopher. It is surely this uniquely human ability of consciously deciding to use one's abilities otherwise than for the function for which they were 'designed' by the evolutionary process, that represents the philosophers' and prophets' conception of freedom.I40 This perspective would also explain why such behaviour is often unintelligible to observers, because our ascription of motivation can be expected to be based on representative behaviour, much as the behavioural modelling proposed above is based on Homo biologicus. This individualistic behaviour is

140 As I understand the discussions, this conception of freedom is qualitatively different from the "negative" and "positive" categories which generally shape the analyses of philosophers; see Sen, 'Freedom of Choice', pp. 272-279, passim.

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no Ionger interpretable as variation about a mean: it exists in a completely separate space. The hypothesis may also cast light on mental illness, as "we identify as mad those people who Iack a species-typical nepotistic perception of their interests or who no Ionger care to pursue them", 141 and three processes appear likely to Iead to such ascriptions of madness. The first is the dysfunctional operation of cognitive programs, whether caused intemally or extemally. An example would be the malfunction of a cognitive process through the absence of a hormone, or the failure of a of a bird to sing normally due to its confinement to a laboratory as a chick. The second is the functional operation of cognitive programs, but in a manner which is not "species-typical", as in those subject to panic disorder. The third is the conscious decision not to conform to the expected customs and behaviour of the surrounding society, and indicates why so many exceptional individuals have, through the exercise of their freedom, been rnisunderstood, persecuted, or classed as insane.

141 Daly and Wilson, Homicide, p. 80. For further suggestive discussions about the relationship between psychiatry and evolutionary theory see Randolph M. Nesse and AlanT. Lloyd, 'The Evolution of Psychodynamic Mechanisms' in Jerome H. Barkow, Leda Cosmides, and John Tooby (eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, pp. 601-624 (Oxford: Oxford University Press, 1992); Kaiman Glantz and J ohn Pearce, Exiles from Eden: Psychotherapy from an Evolutionary Perspective (New York: W.W. Norton, 1989).

15 Elworthy

VII. Summary and lmplications This work reports the results of a search for a methodologicat framework within which general human characteristics can be understood, and which could provide a unified model of man to reptace or complement the particular approaches of the different human sciences. The fundamental premise has been that such a generat model is in fact possible, and that it must rest upon the reasons for which behaviour was 'designed': the survival of genetic replicators in the environment of evolutionary adaptedness. Chapter II set out the necessary evolutionary theory, and concluding that setection applies, and adaptations have emerged for, three principal vehicles: genets, kin-groups, and groups. The following two chapters exarnined the characteristics of adaptations in general, and of the human cognitive programs that underlie behaviour in particutar. Chapter V specified the generat maximisation conditions derivable from evolutionary theory, and these were illustrated with examples of psychological traits which appear to instantiate such maximisation. Chapter VI indicated how behaviour could be modelled through Homo biotogicus, and a comparison with hypotheses based on Homo oeconomicus indicated that the evolutionary approach is likely to provide a superior model of human behaviour. Finally a vision was outlined of the human sciences being linked by a common Homo biologicus, and some of the wider implications of the approach were discussed in the context of criticisms of evolutionary research into human characteristics. As has been stressed above, Homo biologicus is a "candidate" model of man that has been characterised with a few broad brush strokes, rather than in the mass of detail associated with other models of behaviour such as Homo oeconomicus. lt is my conviction, however, that the provision of a firm scientific basis in evolutionary theory means that the potential offered by Homo biologicus substantially exceeds that of conventional models in the social and human sciences. As yet this potential is unrealised, and no attempt has been made to empirically demoostrate the superiority of specific hypotheses built within this evolutionary framework. An indication has, however, been made of particular problems and anomalies which might be resolved through the use of Homo biologicus, and readers may find simitar opportunities in their own

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227

disciplines. The path is thus open for the application of this general approach to specific aspects of human psychology and behaviour, and the linking of such detailed research into human sciences united through their common evolutionary base. In addition to the possibilities that are thus opened for the human sciences, the approach has potential implications for more philosophical issues. Some, such as the perspectives developed on hierarchies of function and mechanism, would appear to provide helpful insights into disputes about appropriate modes of scientific enquiry. Others, such as the ascription of maximisation to each human being, the recognition of the genetic, developmental and situational contributions to human diversity, or the distinction made between being "free to choose" and the freedom of 'cognitive hi-jacking', have relevance to profound ethical and moral issues. A final implication, related to many of these specific implications but more general than any of them, is the potential contribution to the fulfilment, for each individual, of the process so closely associated with the oracle at Delphi: to know thyself.

Glossary The following expressions are intended as explanations of the majority of specialised vocabulary used, and as concise definitions of terms that have beeen given a special meaning. The biological explanations are generally adapted from existing dictionaries and glossaries. 1 The meanings of many terms are to be found in the text, and are normally marked with "definition of' under the appropriate entry in the subject index. adaptation A functional structure shaped by the selection pressures of the evolutionary past. adaptationist program The hypothesis that adaptations maxirnised the survival of 'their' genetic replicators in the evolutionary past, but that inclusive fitness may not be maxirnised in the present (cf. adaptionist program). adaptativist program The hypothesis that organisms in the present maximise their inclusive fitness. algorithm A procedure for computation or problem-solving. allele A gene is only able to occupy a specific region of a chromosome - its locus. At any give locus there may exist alternative forms of the gene within the population, and these alternatives are termed alleles (for allelomorphs). Allen's rule The generalisation that the extrernities (such as ears) of mammals tend to be relatively shorter in colder climates than in warmer ones. allopatric speciation The differentiation of, and attainment of complete reproductive isolation of, populations that are completely geographically separated. altruism Behaviour which results in net costs to an organism and benefits to vehicles other than the genet i.e., it may be devoted to or divided between kin-groups and groups. amenorrhea An abnormal absence of menstruation.

In particular: R.J. Lincoln, G.A. Boxshall, and P.F. Clark, A Dictionary of Ecology, Evolution and Systematics (Cambridge: Cambridge University Press); Collins Dictionary; Dawkins, Extended Phenotype; Daly and Wilson, Sex, Evolution, and Behavior.

Glossary

229

anovulation An abnormal failure of the ovary to produce and discharge eggs. autosome A chromosome that is not a sex chromosome. avunculate The practice whereby males provide resources to the offspring of female kin, especially sisters. behaviourism A school of psychology that focuses on objective observable behaviour of organisms and posits the existence of general-purpose learning mechanisms (cf. evolutionary psychology) Bergmann's rule The generalisation that geographically variable species of warmbloaded vertebrates tend to be represented by !arger races in the colder parts of their range than in the warmer. biological opportunity set All the possible combinations of outputs that an organism may have the capacity to produce. biological transformation locus the northeast boundary of the biological opportunity set. biophobia An emotional rejection of biological research into human characteristics. cancellation (choice theory) The cancellation of factors that result in the same outcome independently of one's choice (equivalent expressions are "independence" and the "sure-thing principle"). candidate theory A theory or hypothesis which is affered as a possible explanation for specific phenomena but for which empirical hypothesis testing has not taken place. ceteris paribus Other things being equal. chromosome One of the chains of genes found in cells. In humans there are forty-four autosomes and two sex chromosomes. cistron A length of chromosome responsible for the encoding of one chain of arnino acids in a protein. codon A triplet of units in the genetic code, specifying the synthesis of a single arnino acid in a protein chain. coefficient of relationship (r) A measure of kinship varying from 0.0 (unrelated) to 1.0 (genetically identical), representing the probability that a focal allele will be identical in two organisms through descent from a recent common ancestor (cf. correlation of relatedness).

230

Glossary

cognitive Ievel A description of psychological mechanisms in functional terms, as programs that process information. cognitive program a description of the algorithm required for a functional cognitive ability. Cognitive programs will generally make use of Darwinian algorithms (q.v.) and be instantiated in brain cells, but can be specified independently of these lower Ievels. community etTort (CE) Effort expended by individuals due to mechanisms which were selected because of their advantages for the group vehicle in the environment of evolutionary adaptedness. computational theory A description of the goal of a cognitive program (q.v.) and the necessary associated information and parameters. conspecific Belonging to the same species. convergent evolution The independent evolution of similar forms in unrelated or distantly related lineages that is not based on genetic similarity. Cope's rufe An empirical generalisation that evolutionary trends towards !arger body size are common. coreplicon A unit within a genome containing genetic replicators whose survival is maximised in the same way. correlation of relatedness (F) A generalisation of the coefficient of relationship, where factors other than descent from a recent common ancestor may cause higher than species-typical relatedness. cytoplasmic genes Genetic replicators that exist independently of the chromosomes and replicate by an independent process at least part of the time. Darwinian algorithm a description of a specific psychological ability, such as the "Iook for cheaters" algorithm, that serves as a mechanism for a more general cognitive program diminishing marginal productivity A relation such that constant increments to the inputs in a productive process result in decreasing increments in the Ievel of production. dimorphism The occurrence in a species of two distinct types of individual. diploid A cell is said to be diploid if it has chromosomes in pairs - in sexual cases one from each parent. An organism is said to be diploid if its body cells are diploid. Most sexual organisms are diploid (cf. haploid).

Glossary

231

DNA Deoxyribonucleic acid; the primary material within a cell in which genetic replicators are encoded (cf. RNA).

domain specificity The hypothesis that cognitive structures will be tailored to specific domains, rather than general-purpose problem-solving structures.

dominance (biology) A gene is said tobe dominant to one of its alleles if it suppresses the phenotypic effect ofthat (recessive) allele when the two are together.

dominance (choice theory) The principle of maximisation. driving chromosome A sex chromosome that favours its own sex, despite having deleterious effects on the other genetic replicators in the organisms which it finds itself (cf. outlaw gene).

encephalisation quotient The deviation from the trend line relating body size and brain size which estimates the amount of "extra" processing ability the species possesses.

encephalisation The enlargement of the brain relative to the body, and is defined as the residual for the species from the allometric relationship relating body size and brain size.

environment of evolutionary adaptedness (EEA)

A statistical composite of the adaptation-relevant properties of the ancestral environments encountered by members of ancestral populations, weighted by their frequency and fitness-consequences.

epigenesis The development of an organism through continuous interaction between the organism and its environment (cf. preformationism).

evolutionarily stable strategy (ESS) A strategy such that, if most of the members of a population adopt it, there is no 'mutant' strategy that would give higher reproductive fitness.

evolutionary psychology The discipline of investigating cognitive processes from an evolutionary perspective.

ex ante Something specified before the event (cf. ex post). ex post Samething specified after the event (cf. ex ante). exon That portion of a DNA strand that codes for a protein (cf. intron). expected utility maximisation The process of finding what is expected to be the preferred situation.

232

Glossary

extended phenotype A concept developed by Dawkins, including all effects of a genetic replicator on the world. fitness ( w or W) A terrn with many different and confusing meanings and often used as the equivalent of inclusive fitness. In the text it is used in the sense of the amount of successful replication of genetic replicators in one generation. fitness indifference curve A line that represents the same net benefit to the survival of the genetic replicators 'for' the adaptation, either through contributing to the functionality of a vehicle directly, or via one of the subordinate Ievels. fitness price line A curve whose absolute slope reveals the consequences, in terrns of replicator survival, of changes with respect to a particular trait. gene A unit of heredity which may be defined in different ways for different purposes. The expression is typically replaced by "genetic replicator" in the text due to the concem with general principles rather than the specific characteristics of the units of heredity. gene pool The genetic replicators in a breeding population. gene-line The potentially immortal genetic contents of gametes and the cells that give rise to gametes. genet The organism as a vehicle upon which selection may act (cf. ramet). genetic code The biochemical basis of heredity; the sequence of units on the DNA polynucleotide chain that encodes genetic inforrnation. genetic drift The occurrence of random changes in the genetic replicator frequencies, typically in small isolated populations. genetic Ioad The difference between the environment that the population is adapted to and the current environment. genetic replicator A generalised terrn for gene. Any ponion of genetic material that potentially lasts for enough generations to serve as a unit of selection. genetic variation Variability among the alleles at a locus, upon which selection may act. genome The entire set of genetic replicators possessed by an organism. genotype The genetic characteristics of an organism at a particular locus or set of loci, often used as the genetic Counterpart to phenotype.

Glossary

233

haploid A cell is said to be haploid if it has a single set of chromosomes. Gametes are haploid, and when they fuse in fertilisation a diploid cell is produced. Some organisms, such as fungi and male bees, are haploid in all their cells, and are referred to as diploid organisms. heritability The degree, ranging from 0.0 to 1.0, to which the phenotypic variance of a trait among members of a population is related to genotypic variance. heuristic A problem-solving method that uses non-analytical techniques, such as general rules or past experience. Homo biologicus A model of human behaviour based on the hypothesis that the cognitive programs underlying behaviour were shaped in the environment of evolutionary adaptedness to solve domain specific problems. Homo oeconomicus A model of human behaviour based on the hypothesis that humans will be selfish, rational, and will maximise utility. Homo sociologicus A model of human behaviour based on the hypothesis that humans behave appropriately to the environments in which they fmd themselves and which stresses social effects such as group dynarnics and mores. host Any organism that provides food or shelter foranother organism (cf. parasite). inclusive fitness The total contribution made by an organism to the survival of its genetic replicators, through both its own offspring and the members of its kin group and group. independence (choice theory) The cancellation of factors that result in the same outcome independently of one's choice (equivalent expressions are "cancellation" and the "sure-thing principle"). inditTerence curve A conceptual economic line showing the points where the person under consideration is indifferent between the respective amounts of two or more goods. infantleide Any form of Iethai curtailment of parental investment in offspring brought about by conspecifics. inheritance The transmission of genetic information from ancestors (or parents) to descendants (or offspring). iastantiation The realisation of an abstract process in a particular mechanism. intron That portion of a DNA strand that does not code for a protein (cf. exon).

234

Glossary

invariance (choice theory) The principle that he way a problern is presented should not affect its logical analysis. K-selection Selection for the qualities needed to succeed in stable, predictable environments. Qualities typically assumed to be favoured by K-selection include !arge body size, long life, and a small number of intensively cared-for young (cf. rselection). kin Genetic relatives such as siblings or parents and offspring. kin-group The groupings of kin in a population on which selection may act. lineage A line of common descent. locus The position on a chromosome occupied by a genetic replicator. marginal productivity The increases in the Ievel of production resulting from increments in the inputs to a productive process. maximisation The choice of the highest-yielding among the available possibilities (cf. optimisation). meiosis The kind of cell division in which a cell (usually diploid) gives rise to daughter cells (usually haploid) with half as many chromosomes. meme A unit of cultural inheritance, proposed by Dawkins as cultural equivalent of a genetic replicator. methogological individualism The doctrine that explanations should be framed in terms of the behaviour of individuals, rather than supra-individual entities. mitosis The kind of cell division in which a cell gives rise to daughter cells possessing a full complement of chromosomes. monogamy An exclusive mateship of one female with one male. mutagen An agent that produces, or enhances the rate of, mutation. mutation An inherited change in the genetic material. neoteny An evolutionary slowing down of bodily development relative to sexual maturity. nepotism Discriminative behaviour by an organism that favours its relatives.

Glossary

235

net aggregate value (NA V) The current value of a stream of costs and benefits resulting from the somatic, reproductive, and community effort aspects of a particular action. net present value (NPV) The current value of a stream of costs and benefits which have been appropriately discounted. net community value (NCV) The current value of a stream of costs and benefits resulting from community effort net reproductive value (NRV) The current value of a stream of costs and benefits resulting from reproductive effort net somatic value (NSV) The current value of a stream of costs and benefits resulting from somatic effort neutral mutation A mutation that has no selective advantage or disadvantage in relation to its allele. numeraire A good that can be used as a unit of account and a store of value as a substitute for, or generalisation of, money. ontogeny The development of a particular organism over its life-time. opportunity cost The cost of an activity in terrns of opportunities foregone. optimisation The achievement of the highest-yielding among all possibilities (cf. maximisation). outlaw gene A genetic replicator that is favoured by selection at its own locus, despite having deleterious effects on other genetic replicators in the organisms which it finds itself (cf. driving chromosome) ovulation The production and release of ova by the ovary. paleoanthropology The branch of anthropology concemed with hominids and prehistoric man. parasite Any organism which is metabolically dependent on another living organism (the host) for the completion of its life cycle, and which is typically detrimental to the host. parental Investment Any investment by a parent in an offspring. parthenogenesis The development of an unfertilised ovum into an individual organism.

236

Glossary

phenotype A visible form of life created by the interaction of a particular set of genetic replicators with their environment. phobia A compelling fear or dread. phylogeny Evolutionary development over generations plasmids Rings of DNA that exist outside the chromosomes. Examples of cytoplasmic genes. pleiotropy The phenomenon whereby a change at one genetic locus can bring about a variety of apparently unconnected phenotypic changes. polyandry The mating of one female with more than one male (cf. polygyny, monogamy). polygamy Polygyny and/or polyandry polygyny The mating of one male with more than one female. preformationism The hypothesis that the form of the adult body is in some sense mapped in the zygote (cf. epigenesis). production possibility curve An equivalent term for transformation locus; the northeast boundary of the productive opportunity set. productive opportunity set All the possible combinations of outputs that an individual or firm may have the capacity to produce. propositional calculus A system of symbolic logic concerned only with the relations between propositions as wholes, taking no account of their internal structure. r-selection Selection for the qualities needed to succeed in unstable, unpredictable environments. Qualities typically assumed to be favoured by K-selection include fecundity and small body size. ramet The organism as an entity that grows and acts as a mechanism for one or more vehicles, such as through somatic, reproductive and community effort. rationality A confusing concept that rests on the assumption that reason and logic are the most appropriate methods of problem-solving. The Wason selection task shows that cognitive processes that are illogical in formal terms may be weil suited to solving important problems. recon The minimum unit of recombination.

Glossary

237

replicator Any entity of which copies may be made. reproductive eß'ort (RE) Effort expended by individuals due to mechanisms which were selected because of their advantages for the kin-group vehicle in the environment of evolutionary adaptedness. reproductive value An organism's expected lifetime reproductive output. RNA Ribonucleic acid; a polynucleotide that governs protein synthesis in a cell and that may also serve as the chemical base for genetic replicators (cf. DNA). selection Non random differential reproduction of different genotypes in a population. sex chromosome A special chromosome concerned with the determination of sex. sociobiology The study of the biological basis of social behaviour. somatic eß'ort (SE) Effort expended by individuals due to mechanisms which were selected because of their advantages for the genet vehicle in the environment of evolutionary adaptedness. speciation The formation of new species (cf. allopatric speciation, sympatric speciation) sure thing principle (choice theory) The cancellation of factors that result in the same outcome independently of one's choice (equivalent expressions are "cancellation" and "dominance"). sympatric speciation The differentiation and attainment of reproductive isolation of populations that are not geographically separated and which overlap in their distributions (cf. allopatric speciation) taxonomic categories A hierarchical system arranged in an ascending series of ranks. In zoology seven main ranks are recognised: Kingdom, Phylum, Class, Order, Farnily, Genus, Species. taxonomy The theory and practice of describing, narning, and classifying organisms. teleonomy The science of adaptation. transformation locus An equivalent term for production possibility curve; the northeast boundary of the productive opportunity set. transitivity (choice theory) lf x > y and y > z, then x > z. Intransitive preferences would expose the decision-mak:er to being used as a "money-pump".

238

Glossary

utility A economic concept of value based on a rank ordering of preference. The statements "A is preferred to B" and "A has a higher utility than B" are equivalent. vehicle The entity in which genetic replicators exist, and upon which selection acts. A vehicle is a generalisation of the idea of a phenotype, in the same way that an active germ-line replicator is a generalisation of the idea of a gene. zygote The single cell produced by the fusion of gametes, before mitotic divisions have begun.

Subject Index Adaptationist program see Program, adaptationist Adaptations and approximations 65, 66, 114 and expressed traits 69, 70 definition of 15, 34, 38, 49, 69 function of 28, 48, 65, 69, 146 Ievels of 49 non-optimal 16, 60, 65 perspectives on 40, 86, 158 Adaptive Iandscape 17, 60, 62, 63 Adaptivist program see Program, adaptivist Agentie state and group selection 200 and obedience 163 cues for 209 Agoraphobia explanation of 121 rates of 121 Alleles 12, 50 Allen's rule and human diversity 126 Altruism and social behaviour 25 definition of 22 in the farnily 175 reciprocal 25 Amenorrhea and anorexia nervosa 128 Anorexia nervosa definition of 128 explanation of 128 Arms race evolutionary 11, 104, 105 Artificial Intelligence strategies in 206 As if assumption of 171 , 174, 175, 188

Asch experiments design and results 154 Authority and obedience experiments 153 Autonomous agents characteristics of 208 Avai1ability theory and Wason task 90 Avunculate definition of 140 explanation of 141 Balance of power and encephalisation I 03, 106 and sociality 108 neglect of hypothesis 110 Behaviour adaptiveness of 114 as mechanism 49, 69, 173 by vehicles 49 definition of 49, 69 in war 198 mechanisms underlying 71, 167, 174, 179 modelling of 1, 83, 167-169, 171, 174, 185, 196, 201, 204, 220, 225 Behaviourism and conditioning 81 and language 78 and leaming 81 Bergmann's rule and human diversity 126 Bio1ogical opportunity set and phenotype set 54 characteristics of 59 Biology see Evolutionary theory Birds development of 51

240 song of 40, 41, 47, 48, 51, 53, 57, 232 tails of 13 Body size and sexual dimorphism 125 and species selection 29 Brain and intelligence 106 information processing capacity 94 size of 93 structure of 71, 93, 163 Brainworm and expropriation 115, 224 Cancellation falsification of 184 Cheating and Wason task 87 mechanisms to detect 89, 92 Choice and domain specificity 186 consumer 172, 194 of habitat 118 under uncertainty 88, 175, 181, 185, 188 Chromosomes driving 31 gavone of 30, 149 sex 51 Circumscription theory of social evolution 107 Cistrons 7 Coefficient of relationship 23, 25, 134, 146 Cognitive dissonance and community effort 199 Cognitive Ievel definition of 73 Cognitive programs. See also Mechanisms, psychological and Homo biologicus 188, 205, 210 and mating effort 137 as mechanism 40, 113, 172 definition of 75, 82 extent of 81, 223 for habitat selection 120, 174 for infanticide 131, 132

Subject Index for panic 122 heuristic character of 205 Collective action and community effort 200 theory of 31, 197 Community effort and aggregate maxirnisation 165 definition of 113, 146 examples of 199 typical panern of 118 Comparative method and phylogeny 45 Comparative-static form of analysis 203 Competition and community effort 118, 148, 149 between fmns 60 between groups 106, 203 inter-male 125, 126 status 124 Complex functions analogy of 41 Complexity 3, 13, 19 Computational theory and algorithms 77, 205 and solvability 77 and transformational grarnmar 78 definition of 76 of obedience 160 Computer analogy 5 Conditional strategies and human diversity 126 Conditional strategy rape as 142 Conforrnity as community effort 157, 200 experiment design 153 experimental resu1ts 154, 156 Conscience ro1e of 161, 162 Constraints and cognitive processes 77 and sing1e exit 169. 223 historical 60, 61, 64, 114 on brain size 97 Content effect and Wason task 86

Subject Index Cooperation and comrnunity effort 118, 148 within groups 203 Cope's rule 29 Coreplicons definition of 32 implications of 33 Correlation in share price model 191 of relatedness 22, 25, 146 Cost-benefit analysis and brain size 97 and reproducti ve effort 134 and social contracts 88 and somatic effort 114 and unprofitable investment 128 and Wason task 89 dynarnics of 116 Culture as confusing concept 175 interpretation of 221 Darwinian algorithms agentic shift 163, 164, 200 and agentic shift 209 definition of 82 Iook for cheaters 91, 187, 205 role of 82, 205 Deterrninism allegation of 221 and free will 222, 223 and mechanisms 222 of cognitive programs 222 Development 12 and strategies 140 epigenesis and 51 human 136 ontogenetic 20, 51 phylogenetic 45 Difference of two Gaussians 77, 88 Discount rate and aggregate maxirnisation 166 and reproductive effort 135 and share prices 190 and somatic effort 116, 11 7, 128 Diversity. See also Variation among genetic replicators 16 16 Elworthy

among individuals 47, 169, 219-221, 223 and discrirnination 220 genetic 11, 12, 57 sub-functional 12 DNA 7, 9 Domain generality and behaviourism 78 and choice 186 and culture 80 non-optimality of 80 Domain specificity advantages of 80 and complex structure 79, 206 and faeces-fruit problern 81 of cognitive programs 79, 149, 174, 175, 206 of language processes 78 Dorninance falsification of 184 Dynamies requirement in models 203 Econornics and biology 180 assumptions in 193 definition of 52 imperialism of 178 maxirnisation in 172 models in 169, 176, 179, 204 neoclassical 169, 170, 202, 223 new home 194 EEA and adaptations 44, 65 and comrnunity effort 147 and invariances 74 and Pleistocene 75, 120 and reproductive effort 134 and somatic effort 113 definition of 41 Effort types of 113, 136, 188, 203 Emergent functionality definition of 207 Encephalisation across species 95, 98 definition of 94

241

242 hominid 98, 100, 148 quotient of 95 speed of 106 Environments and adaptation 65, 232 choice of 118 definition of 51 effect of 51, 52, 140, 169 Epigenesis 51 ESS and replicators 18 definition of 16 Ethnocenuism and community effort 199 Evolution convergent 61 social 101 Evolutionary psychology definition of 72 importance of I, 4, 202, 210, 216 methodology of 73, 86, 143, 160, 165, 168, 210 Evolutionary theory. See also Sociobiology and econornics 59, 179 and human characteristics and Nazis 212 and variation I 0 as explanation of life 3 as tautology 36, 64 Exons 7 Expectations and aggregate effort 166 and group effort 147 and reproductive effort 139 and share prices 190 of genetic relationship 134 uncertainty of 117, 134 Expression phenotypic 11, 51, 68 Expropriation see Trade Extended phenotype example of 115 interpretation of 68, 224 Eyes and EEA 44

Subject Index structure of 62 Farnilies altruism within 195, 202 as maxirnising units 175, 194 behaviour of 196, 209 conflicts within 194, 195, 197 econornics and 194 Fitness as difficult concept 23, 36 definition of 14, 22 dirninishing marginal 56 inclusive 22, 23, 25, 35, 68, !58 Fitness indifference curve and maxirnisation 58 convexity of 56 tangential to price line 57 Fitness price line and non-maxirnisation 60 and trade 70 definition of 57 Freedom acadernic 220 and predictive models 168 and trade 224 as unintelligible 224 of choice 222, 223 profound 224 Functional explanation 20, 47, 160 Ganglion cells 61, 63 Genepool and ontogeny 50 rnixing of 137 Genes. See also Genetic replicators outlaw 30, 31 parliament of 31 Genetic drift and optimality 63, 64 and speciation 18 definition of 16 Genetic Ioad estimate of 65 Genetic prograrnrning power of 206 Genetic switch and development 51

Subject Index Genets and somatic effort 114, 195 definition of 20, 21 Genome 30, 33, SI Genotype 25 Grammar of social contracts 88 Group selection see Selection, group Groups differences between 218 low-migration 27 relations between 106 specification of 25 Growth and reproduction 19, 20 H-Y Antigen 51 Heisenberg uncertainty principle of 223 Heuristics and adaptivism 140 and cognitive programs 205 and Homo biologicus 210 and science 36 Hierarchical reductionism I, 5 Hierarchy and analyses 202 and non-linearity 203 and organisations 163 as fundamental principle 3 disciplinary 4, 210 of life 4, 8 of mechanisrns 4, 49, 71, 113, 134, 167, 206, 210, 221, 222, 224 recursion and I 5 Hijacking by Cuckoo 69 cognitive 224 physiological 224 Histone H4 gene 8 Homicide explanations of 216 Homo biologicus and behaviour modeHing I, 83, 201 , 202, 204, 221, 223

and Homo oeconomicus 2, 173, 175, 193, 201 as candidate model 170, 201 as evolutionary model I, 202 as interface I characterisation of 170, 177 complex psychology of 175, 204 instantiation of 204 precursors of 180 simulation of 210 Homo oeconomicus and egoism 174, 195 and social science I and war 198 characteristics of 170, 171, 173, 176, 189, 195 inadequacy of 2, 188, 189, 193, 195, 201 Homo sociologicus and social science characteristics of 177 lndifference curves convexity of 56 fitness 57, 60 lndividuals. See also Organisms psychology of 174 representative 114, 116, 117, 134, 147, 169, 170, 174,221,223,225 lndustrial melanism among moths 10 Infanticide definition of 128 reasons for 129, 131, 132 research into 214 Information processing and rationality 205 as methodology 204 Inheritance 4, 6, 7 Intelligence increases in 106 measurement of 221 Ioterests differences between 195, 197 national 197, 198 International relations

243

244 realist school of 196 Introns 7 1nvariance falsification of 184, 186 Invariances and cognitive prograrns 74, 77 identification of 74 Irrationality and choice problerns 184 and rnarkets 192 and reproduction 146 and risk 123 Isolation 18 Justice and cornrnunity effort 200 Kibhutzirn and Westerrnarck effect 138 Kin and altruisrn 146 and sexual preferences 137 re1ationships between 25 Kin selection see Selection, kin Kin-groups and reproductive effort 134, 195 definition of 21 Language and EEA 44 Life artificial 209 cornplexity of 3 forrnation of 7 Life cycle and econornics 203 and sensecence 50 exarnple of 118, 136, 203 of growth and reproduction 20, 165 Lineages and inertia 17 Linking of disciplines 2, 202, 210, 211 Markets and Homo biologicus

Subject Index characteristics of 189 efficiency of 189, 190 for securities 175, 188 Mating effort and cognitive prograrns 137 definition of 136 Maxirnisation aggregate 165, 167, 168, 221, 224 and optirnisation 64 and sornatic effort 114, 172, 188, 195 and trade 224 by genets 113, 114, 165, 187, 196 by groups 146, 147, 149, 158, 163, 165, 187 by households 194, 195, 197 by kin-groups 35, 133, 146, 165, 187, 195 econornic assurnption of 174, 179, 188, 202, 223 in different spaces 115, 116, 135, 147, 166, 172, 174,221 of replicator survival 65, 113. 116, 134 through selection 97 utility 174, 195 Mechanisrns functional 49 hurnans as 212 rnorphological 71 physiological 72, 163, 224 production of 53 proxirnate 48, 49 psycho1ogical 40, 71, 82, 149, 160, 164, 168, 169, 171, 204. See also Cognitive prograrns Meiosis 12, 30 Mental illness interpretation of 225 Mental organs see Cognitive prograrns Mesh between world and perceptions 74 Methodological individualisrn irnportance of 174, 176 Methodology for Homo biologicus 205, 209

Subject Index for human sciences 202, 205, 208, 211 information-processing 204 of economics 209 Migration 27 Milgram experiments design of 149 interpretation of 159, 164, 200 results 151, 152, 157, 159 Mitosis 12 Morality and conscience 163 Moths and ind ustrial me1anism 10 and non-optimality 65 Mutagens 9 Mutation pressure 9 Mutations 9, 16, 17, 62, 63 Mutons 7 Myth

of cultural malleability 216, 217, 221 of modern anthropology 106 of Social Darwinism 216 Nature and nurture 51 Neoteny and optimality 64 Nepotism and madness 225 extraparental, defined 136 Net ... value see Value, net ... Net community value specification of 147 Obedience and cognitive programs !58, 209 as community effort 157, 166 in concentration camps 158 in Milgram experiments 157, 200 preconditions of 209 Ontogenetic explanation 40, 164 Ontogeny and branching structure 82, 169 and buffering 63

and obedience 164 definition of 12 phases of 83, 203 Opportunity cost and fitness 56 and parental investment 136 Optimisation and adaptations 36 and expressed traits 36, 60 and maximisation 64 assumption of 36 constraints on 59, 114, 205 Organelles 19 Organisms. See also Individuals as mechanisms 21, 28, 49, 53, 224 as vehicles 21 origin of 19, 20 roJe of 21 Ostracism and community effort 200 Panic as adaptation 121 Panic disorder explanation of 121, 225 rates of 121 Parasites and deception 70 and hosts 10 and sex 11, 12, 16, 29, 61 and somatic effort 116 Parental care by substitute parents 131 by warhier 70 Parental investment and infanticide 129, 131 and numbers of children 38 definition of 136 differential 127, 139 Pascal' s wager definition of 182 Patemity confidence and rape 142 and reproductive strategy 140, 141 Phenotype and genetic replicators 8 Phylogenetic explanation 40, 87, 160

245

246 Phylogeny definition of 41 of cognitive development 93, 94, 105 of obedience 160 reconstruction of 45, 62 Pleistocene as EEA for psyche 75 Polygyny and sexual dimorphism 125 generality of 125 Population genetics and fitness indifference curves 56 and group selection 27 Preference reversal definition of 186 Preferences and Homo biologicus 208 and utility function 169, 180 by rapists 144 for environments 120 sexual 137, 139 stability of 173 Probability and choice theory 182 classical 182, 183 estimates of 187 subjecti ve 184 Production function biological 53, 56, 59, 62, 64, 65 Production possibility curves 56, 60 Program adaptationist 35, 71 adaptivist 35, 60, 71 and programme 35 Programs cognitive; see Cognitive programs Race genetic component to 218 Ramets definition of 20 Random walk of share prices 190 Rape as reproductive strategy 142 interpretation of 142, 213

Subject Index penalties for 143 victim characteristics 144 Rational actor see Homo oeconomicus Rationality economic assumption of 158, 175, 192. 210 in somatic domain 175 procedural 204, 205, 207 substantive 204, 205, 207 Rats development of 51 Recons 7 Reductionism as scientific technique 5, 179 misunderstanding of 5 Reflection effect definition of 186 reasons for 187 Replicators active germ-line 6 and vehicles 48 characteristics of 6, 7 coadapted 66 genetic 4, 6, 11, 12, 23. 28, 49, 51, 55, 62, 65, 66, 165, 232 memes 28 species 29 strategies of 18 survival of 8. 10, 13, 49, 50. 57, 60, 113, 134, 167, 172. 221' 224. 232 types of 6, 33 Reproduction and growth 19, 20 asexual 11 oviparous 95 sexual 137 suppression of 127 viviparous 95 Reproductive effort and aggregate maximisation 165 and cooperation 148 definition of 113, 134 types of 136 typical pattem of 118, 136, 203 Reproductive strategies and avuncu1ate 140

Subject Index and pairbonding 140 and rape 143, 214 cognitive programs for 146, 174 definition of 139 ranking of 140 Resources function of 118 limited 54 somatic 116, 139, 143, 173 Risk and disputes 123 and insurance 20 I and panic 122 and reflection effect 186 and young men 126, 127, 143 assessment of 174 Science and rationality 175 as discovery 170, 201 falsification within 176, 202, 210 generalisations and 168, 169 human I, 170, 174, 202, 203, 210, 211 linking within 202 normal 201 social 1 Selection agents of 13 and migration 27 artificial 13 effects of 15, 148 frequency dependent 12, 15, 16, 61 group 15, 24-26, 29, 148, 158, 160, 199 group and kin 25, 26 kin 23, 25, 26, 137 Ievels of 9, I 3, I 5, 33, I 48 model of 14, 22 natural 4, 13, 25, 28, 49, 60, 62, 65, 97, 165 pressure of 15, 28, 30, 57, 62, 166 Price-Hamilton analysis 14, 22, 28 sexual 13, 127 species 29 stabilising 66 Senescence

pleitropic theory of 50 Sex and differentiation 51, 125, 137, 214, 217, 218 explanation of 11, 16, 29, 61 Sim-pua and Westermarck effect 138 Situation and influences 168 logic of 169, 170, 223 Situational determinism and behaviour 205, 223 definition of 170 Social Darwinism influence of 215 Social exchange see Trade Sociality and balance of power 104, 148 and discrimination 220 of humans 101, 103 reasons for 101, 102 Sociobiology criticisms of 38, 212, 221 Software as analogy 72, 82, 206 Somatic effort and aggregate maximisation 165 and cooperation 148 and unprofitable investments 127 as investment 116 definition of 113 expected costs of 114 typical pattern of 118, 203 Specialion allopatric 18 formation of 18 general 18 sympatric 18 Species and Homo biologicus St. Petersburg paradox of 182 States behaviour of 175, 196, 202, 209 formation of 107 Status quo

247

248 and choice 187 Suicide ex,lianations of 176 Survival of replicators 19, 48 of the fittest 36 Survival of genetic replicators see Genetic rep1icators, surviva1 of Tastes see Preferences Te1eonomy definition of 47 Time 1ags and approximations 65 Trade and expropriation 69 and fitness price line 70 and somatic effort 116 and Wason task 86 between vehic1es 224 by Cuckoo 69 cognitive program for 205 Traits analysis of 54, 219 behavioural 28 expressed 4, 12, 36, 45, 51, 69, 149, 167, 224 function of 47 morphological 28, 45 Transformation locus and non-optimality 64 specification 55, 57, 58, 60 tangential to price line 57 Transitivity falsification of 184 Unity and group success 149 of households 194 of states 197, 198 Utility expected 183, 196 predecessors of 183 Uti1ity function for households 195 specification of 169, 180

Subject Index Value net community 147 net present 117, 135 net reproductive 135 net somatic 117, 121 Variation. See also Diversity and predictability 169, 223, 225 and share prices 190, 192 between groups 218 functional 220 genetic 10, 60, 66, 169, 219, 223 in reproductive success 124 Iack of 61, 62, 64, 114 psychological 170, 219 relative 62 sub-functional 16, 61, 66, 137 supply of 10, 16 Vehicles coreplicon 28, 165 definition of 8 group 28, 147 individual 28 kin-unit 28, 45, 147 roJe of 4 species 29, 165 types of 8, 28, 29, 33, 49, 165 Voting and Homo oeconornicus 198 War and community effort 149, 199 and individual behaviour 198, 202 and state formation 106, 107 Machiavelli' s views on 111 realist view of 196 Wason selection task and availability theory 90 and competing hypotheses 91, 92 and pragmatic reasoning 91 and propositional calculus 85, 186 and social contract theory 90 characteristics of 83, 85 example of 83, 84, 89 Westermarck effect evidence for 138 hypothesis of 138

Author Index Alexander, R.D. 10, 15, 18, 19, 28-30, 34, 36, 38, 40, 41, 45-47, 50, 65, 82, 101-104, 106, 108, 113, 116, 119, 124-126, 129, 130, 136, 137, 141-143, 148, 161, 162, 212, 215, 223 Allais, M. 184 Allen, D.W. 194 Allen, E. 212, 222 Allison, G. 197 Alper, J. 214 Anderson, E. 108 Anderson, J.R. 35 Anderson, T.L. 207 Andersson, M. 106 Ando, A. 203 Andrew, R.J. 48 Ardrey, R. 105 Arkes, H.R. 185 Arrnstrong, E. 95, 97 Arrow, K.J. 169, 189 Asch, S.E. 153, 154 Ashley, R.K. 196 Avise, J.C. 33 Axe1rod, R. 11, 87, 127, 162 Baker, J.R. 40 Bannister, R.C. 216 Barash, D.P. 127, 142 Barkow, J.H. 202 Barlow, G.W. 37 Barnett, W.A. 203 Baron, R.A. 159 Barro, R.J. 194, 195 Barry, B. 162 Bateson, P.P.G. 12, 50, 51, 64, 215 Bäumer, Ä. 213 Baumol, W.J. 203 Beattie, C. 144 Beatty, L. 182, 183

Becker, G.S. 53, 169, 172, 173, 181, 194-196 Beckwith, J. 214 Beer, R.D. 207 Bell, D.E. 185 Ben-Porath, Y. 194 Benbow, C.P. 219 Benedict, R. 218 Benhabib, J. 203 Bemds, W.P. 127 Bemholz, P. 178 Bemoulli, D. 183 Bettelheim, B. 158 Betzig, L.L. 37, 109, 124 Bigelow, R.S. 105 Birch, L.C. 36 Bitterman, M.E. 80 Blake, R.R. 153 Blatt, J.M. 188 Bloom, P. 44 Bogaert, A.F. 219 Bohm, P. 185 Boland, L.A. 188 Boland, L.R. 171 Boone, J.L. 101, 109 Boorman, S.A. 26 Borgia, G. 28-30, 103, 109, 148 Bostic, R. 187 Boxshall, G.A. 228 Boyd, R. 26, 181 B!llhren, 0. 182 Brandon, R.N. 33 Brehm, J.W. 153 Brennan, G. 198, 199 Brockman, H.J. 52 Brooke, M. 68 Brooks, R.A. 207 Brown, J.L. 26 Brown, W.M. 218

250

Author Index

Brues, A.M. 13 Buchsbaum, M.S. 126 Bueno de Mesquita, B. 108, 196, 197 Bull, H. 108 Burke, W.D. 32 Buss, D.M. 137, 139 Byme, D. 159 Byme, R.M.J. 83, 185 Byme, R.W. 110, 111 Cade, W. 142 Caiazza, J.C. 159 Caldwell, B.J. 188 Campbell, D.T. 101 Cap1an, A.L. 37 Caporael, L.R. 200 Carlsmith, J.M. 199 Carneiro, R.L. 3, 107 Carr, E.H. 196 Casper, J.D. 200 Cauley, J. 197, 198 Chagnon, N.A. 107, 131 Cheng, P.W. 91, 92 Chiel, H.J. 207 Chomsky, N. 75, 78, 81, 217 Clark, P.F. 228 Clutton-Brock, T.H. 45, 46 Coase, R.H. 172 Coleman, J.S. 178 Collins 22 Connor, R.C. 86, 87 Cosmides, L. 10, 11, 13, 31, 32, 34, 35, 41, 44, 51, 72-74, 79-82, 84-92, 165, 177. 202, 220 Cowen, T. 173 Cox, J.R. 85, 86, 90 Crawford, C. 128, 213 Crook, J.H. 45, 46, 124 Crook, S.J. 124 Crutchfield, R.S. 153 Curio, E. 47 Daly, M. 4, 40, 41, 45, 48, 51, 52, 73, 123-127, 129-133, 140, 212, 216, 225, 228 Darwin, C. 3, 4, 10, 13, 15, 34, 62, 73, 104, 179

Daston, L. 182, 183 Davies, N.B. 47, 68 Dawes, R.M. 200 Dawkins, R. 3-11, 16-21, 23-25, 28-30, 35, 36, 39, 40, 51, 52, 60-63, 65-69, 71, 72, 98, 105, 115, 215, 222, 228 Dawkins, R.R. 24 De Bondt, W.F.M. 189, 190 de Catanzaro, D. 176 de Waal, F.B.M. 87 DeVore, I. 45, 75, 103, 110 Diamond, J. 108, 109 Dickemann, M. 130 Diehl, P.F. 197 Dizinno, G. 144 Dohl, T.P. 87 Donath, M. 207 Downs, A. 198 Dunbar, R.I.M. 36, 37 Durham, W.H. 109 Eals, M. 219 Eberhard, W.G. 15, 31-33 Edgeworth, F.Y. 179 Edwards, W. 183 Ehrlich, P.R. 36 Eichenburger, R. 189 Eickbush, D.G. 32 Eickbush, T.H. 32 Eisner, R. 201 Eldredge, N. 17 Ellis, L. 144 Ellsberg, D. 185 Ember, C.R. 107 Engel, C. 131 Ervin, F.R. 79 Eshel, I. 26, 27 Evans, J.S.B.T. 185 Evans, J.St.B.T. 86, 90 Falger, V. 199 Falk, D. 97 Fama, E.F. 189 Farberow, N.L. 176 Feinberg, R. 218 Felsenstein, J. 65 Ferejohn, J.A. 198

Author Index Festinger, L. 199 Feynman, R.P. 123 Fiorina, M.P. 198 Fisher, B. 200 Fisher, R.A. 13, 105, 127, 130 Flannery, K.V. 108 Flinn, M.F. 142 Flinn, M.V. 125, 142 Fodor, J.A. 76, 79, 81, 94 Foley, R.A. 18, 97, 120, 213 Forbes, J. 198 Forrest, S. 208 Frank, R.H. 169, 180, 181 Freeman, D. 217 Frey, B.S. 178, 180, 189 Friedman, M. 64, 168, 171, 203, 223 Friedman, R. 223 Froot, K.A. 189 Garcia, J. 79 Gartlan, J.S. 46 Gentry, J.W. 186 Gerhardt, H.C. 12 Gewerke, J. 203 Ghiselin, M.T. 4, 11, 45, 73, 179 Gibson, K.R. 100 Gigerenzer, G. 92, 182, 183 Gilovich, T. 180 Gilpin, R.G. 196 Glantz, K. 225 G1ass, B. 212 Goldsmith, T.H. 44, 62 Goodin, R.E. 198 Gould, S.J. 17, 30, 35, 222 Gow1ett, J.A.J. 111 Graber, R.B. 107 Grafen, A. 23, 106 Grefenstette, J .J. 208 Gregory, M.S. 37 Grether, D.M. 184, 186 Griffitt, W. 159 Griggs, R.A. 85, 86, 90 Groebel, J. 202 Gruber, H.E. 73, 179 Gruter, M. 200 Gunning, J.P. 177 Gutowitz, H. 208

251

Hahn, F.H. 169 Haigh, J. 16 Hamilton, W.D. II, 12, 14, 15, 21-23, 25-27, 30-32, 50, 87, 102, 104, 109, 130, 165 Hamilton, W.J. 67 Hammond, K.R. 185 Hardy, A.C. 63, 64 Hare, H. 22 Harper, J.L. 19, 20 Harris, M. 111 Harvey, P.H. 24, 45-47, 50, 95 Hastings, I.M. 31 Hausfater, G. 12, 129 Heckman, J.J. 195 Heerwagen, J.H. 120 Heiner, R.A. 203, 210 Henderson, P.A. 12 Herrnstein, R.J. 187 Hershey, J.C. 201 Hili, E.M. 128 Hili, K. 131 Hinde, R.A. 202 Hiorns, R.W. 93 Hirschman, A.O. 172, 173 Hirshleifer, J. 53, 56, 57, 117, 169, 178, 181 Hodgson, G. 174 Hofman, M.A. 95, 98 Hofstadter, D.R. 223 Hogarth, R.M. 185 Hogg, T. 208 Holcombe, R.G. 174 Holland, J.H. 206 Holmes, L.D. 218 Holmes, S. 172 Holyoak, K.J. 91 , 92 Hoogland, J.L. 46, 125 Hotz, V.J. 195 Houston, A.I. 40 Howard, M. 108 Howard, R.D. 46, 125 Hrdy, S.B. 129, 214 Huberman, B.A. 208 Hug, K. 92 Hughes, A.L. 35 Hull, D.L. 8

252 Humphrey, N.K. 161, 162 Hunter, D. 201 Hurst, G.D.D. 32 Hurst, L.D. 7, 32, 33 Huth, P. 199 Irons, W. 75, 109, 162 Jablonka, E. 32 Jackson, M.W. 199 Jacob, F. 62 Janzen, D.H. 20 Jarman, P.J. 46 Jensen, A.R. 219 Jensen, R.V. 203 Jerison, H.J. 93-95, 98 Johanson, D.C. 97, 109-111 Johnson, N.R. 201 Johnson-Laid, P.N. 83 Johnson-Laird, P.N. 83, 90 Johnston, T.D. 81 Jones, G. 216 Jordan, D.S. 74 Kaelbling, L.P. 207 Kahneman, D. 90, 184-187 Kalat, J.W. 79 Kamin, L.J. 5, 215. 222 Kaplan, H. 131 Kaupen-Haas, H. 212 Keegan, J. 199 Keith, S.A. 104 Kempter, G. 209 Kennedy, P.M. 108 Keohane, R.O. 196, 197 Kephart, J.O. 208 Kettlewell, H.B.D. 10 Keynes, J.M. 193 Kimura, M. 27 King, J.C. 218, 221 Kinzey, W.G. 110 Kirman, A.P. 169 Kitcher, P. 162, 222 Kleidon, A.W. 192 Klump, G.M. 12 Kngdon, J. 109 Koelling, R.A. 79

Author Index Konishi, M. 51 Koza, J.R. 206 Kragt, A.J.C.v.d. 200 Krasner, S.D. 197 Krebs. D. 213 Krebs, J.R. 11, 105 Kruger, L. 182, 183 Kugler, J. 197 Kuhn, T.S. 171 Kununer, H. 102 Kunreuther, H.C. 201 Lachmann, M. 32 Lack, D.L. 46 Lalman, D. 197 Lamb, M.J. 32 Lancaster, K.J. 173 Lande, R. 105 Landes, E.M. 194 Langlois, R.N. 169, 170 Langton, C.G. 208 Latsis, S.J. 170 Lea, S.E.G. 180 Leigh, E.G. 31 Lenat, D.B. 206 LeRoy. S.F. 189 Leslie, A.M. 81 Lester, D. 176 Levine, E. 51 Levins, R. 26, 215, 217 Levitt, P.R. 26 Levy, S. 208 Lewontin, R.C. 5, 7, 10, 15-17, 25, 33-36, 60, 61, 63, 215, 217, 222 Lichtenstein, S. 186 Lincoln. R.J. 228 Lind, E.A. 200 Lind, H. 185 Lloyd, A.T. 225 Lorenz, H. 203 Low, B.S. 13, 125, 128, 142 Luce, R.D. 187 Luke, T.W. 174 Luttrell, L.M. 87 Lynn, R. 219 MacArthur, R.H. 46

Author Index MacDonald, K. 81, 83 Mace, G.M. 47, 95 Machiavelli, N. 111 Machina, M.J. 182-184 Machlup, F. 170 Maes, P. 206, 208 Majerus, M.E.N. 32 Manktelow, K.I. 84, 86, 90 Manser, A.R. 36 March, J.G. 204, 205 Margolis, H. 179, 181, 187 Margulis, L. 7, 19 Maris, R.W. 176 Marr, D. 63, 76-78, 81 Marshall, A. 172 Marshall, J.C. 76, 78 Martin, R.D. 94-96, 98 Mason, S.F. 7 Masters, R.D. 200, 209 May, R.M. 24, 27, 203 Maynard Smith, J. 9-11, 16, 25, 54, 60, 65 Mayr, E. 35, 40, 47, 179 McCabe, J. 138 McCauley, D.E. 26 McCormick, K. 175 McEvedy, C. 106 McGuire, M.T. 86 McKee, M. 173 McKenzie, R.B. 175, 178 McNarnara, J.M. 40 McNei1, B.J. 185 Mead, M. 217 Mech, L.D. 102 Medawar, P.B. 50 Medio, A. 203 Meehl, P.E. 198 Menefee, G.H. 201 Michael, R.T. 173, 194, 195 Michalewicz, Z. 207 Mi1gram, S. 149-157, 160, 161, 163, 164 Miller, A.G. 159 Miller, L.G. 214 Milner, G.R. 108 Milton, K. 110 Minderhout, D.J. 218 Mitchell, W.A. 36 Mitchell, W.C. 199

Modig1iani, F. 203 Montagu, A. 37 Moran, N.A. 12 Morgenstern, 0. 183 Morgenthau, H.J. 108, 196 Mowen, J.C. 186 Mueller, D.C. 198 Murdock, G.P. 125 Murphy, D.L. 126 Murton, R.K. 48 Nabi, I. 222 Nelson, K. 3, 40, 48 Nesse, R.M. 121, 122, 211, 225 Nevo, E. 13 Newstead, S.E. 185 Ng, Y. 181 Nisbett, R.E. 92 Nishihara, H.K. 76, 77 Noonan, K.M. 46, 103, 104, 108, 125 Norris, K.S. 87 Nottebaum, F. 51 Nozick, R. 174 Nur, U. 32 Nye, J.S. 197 O'Neill, P. 186 O'Sullivan, P.J. 223 Obstfeld, M. 189 Oliver, L.M. 92 Olson, M. 31, 197 Opp, K. 162, 178 Oppenheim, F.E. 197 Oppenheimer, J. 198 Orbell, J.M. 200 Organski, A.F.K. 197 Orgel, L.E. 7 Orians, G.H. 67, 120 Omstein, R. 159 Over, D.E. 84, 86 Packard, V. 188 Packer, C. 87, 103 Palmer, C.T. 35, 143 Parke, W.R. 189 Parker, H. 138 Parker, S. 138

253

254 Parker, S.T. 100 Pascal, B. 182 Pashigan, B.P. 201 Pauker, S.G. 185 Pearce, J. 225 Pearson, R. 215, 219 Peck, J.R. 27 Peters, R.H. 36 Piattelli-Palmarini. M. 78 Pinker, S. 44 Pitt, R. 104, 109 Pittendrigh, C.S. 47, 62 Plotkin, H.C. 33 Plott, C.R. 184, 186 Pollard, P. 90 Pomrnerehne, W.W. 186 Popkin, S.L. 178 Popper, K.R. 169, 171 Porter, T. 182, 183 Powell, T.P.S. 93 Price, G.R. 14, 16 Promislow, D.E.L. 50 Radnitzky, G. 178 Reder, M.W. 185 Rees, A. 52, 172 Regan, D.T. 180 Reilly, R.J. 184, 186 Revusky, S.H. 80 Reynolds, D.K. 176 Reynolds, V. 199 Richardson, P.J. 181 Richerson, P.J. 26 Robbins, L.C. 172 Roberts, J.P. 199 Roberts, K.W.S. 198 Roberts, N. 120 Robertson, M. 24 Rocke!, A.J. 93 Rogers, A.R. 181 Roscoe, P.B. 107 Rose, M.R. 109 Rose, S. 5, 215, 222 Rosenschein, S.J. 207 Rozin, P. 79, 81 Rushton, J.P. 219 Russen, B. 199

Author Index Ruttan, L. 103 Salthe, S.N. 3 Samuelson, P.A. 181 Samuelson, W. 187 Sandler, T. 197, 198 Savage, L.J. 184 Scarr, S. 213, 214 Scharfstein, D.S. 193 Schilt, C.R. 87 Schkade, L. 201 Schnieder, F. 186 Schoemaker, P.J.H. 36, 183, 184, 201 Schotter, A. 198 Schram, A. 198 Schudson, M. 188 Schull, J. 79 Schultz, T.W. 195 Schwartz, B. 76 Schwartz, M.F. 76 Schwartz, T. 198 Scitovsky, T. 188 Scott, J.C. 178 Segar, J. 24 Sen, A.K. 174, 175, 223, 224 Service. E.R. 107 Shaw, R.P. 109 Shell, K. 203 Shepard, R.N. 74 Shepher, J. 138 Sherman, P.W. 40, 41. 46, 125 Shields, L.M. 143 Shields, W.M. 143 Shiller, R.J. 190-192 Shreeve, J. 97, 109-111 Siegelkow, E. 131 Silverburg, J. 37 Silverman, I. 219 Silvers. A. 37 Simrnons, R.T. 200 Simon, H.A. 3, 170, 180. 204, 205 Singer, J.D. 108 Slovic, P. 185-187, 201 Slurink, P. 105. 109 Small, M . 108 Smelser, N.J. 177, 178 Smith, A. 172

Author Index Smith, E.A. 180 Smith, M. 213 Smith, V.G. 108 Sox, H.C. 185 Söderström, L. 203 Staddon, J.E.R. 209 Steams, S.C. 11 Stein, J.C. 193 Stemler, J.G. 201 Sterling, L.S. 207 Stigler, G.J. 169, 173, 178 Strate, J.M. 108 Stringer, C. 99, 100, 106, 126, 218 Strotz, R.H. 201 Sullivan, D.G. 209 Sunday, S.R. 145 Surbey, M.K. 128 Sutch, D. 37 Swijtink, Z. 182, 183 Symons, D. 34-36, 39, 41, 72, 75, 79, 124, 139, 143, 177, 214, 224 Szentagothai, J. 94 Tanese, R. 11 Tarpy, R.M. 180 Taylor, C.E. 86 Thaiss, L. 81 Thaler, R.H. 189, 190 Thoman, E.B. 51 Thomhill, N.W. 138, 140, 143-145 Thomhill, R. 140, 142-145 Thucidides 196 Tietzel, M. 181, 194 Tilly, C. 178 Tinbergen, N. 40, 46 Tinkle, D.W. 104 Tobach, E. 145 Toland, A. 186 Tomes, N. 194 Tooby, J. 10, 11, 13, 31, 32, 34, 35, 41, 44, 45, 51, 72-75, 79-82, 84, 85, 87-89, 103, 110, 165, 177, 202, 220 Trivers, R.L. 22, 86, 87, 125, 130, 136 Tullock, G. 178, 181 , 198, 199 Turabian, K.L. viü Turke, P.W. 34, 37 Tversky, A. 90, 184-187

255

Tweney, R.D. 86 Tyler, T.R. 200 Tyrrell, T. 206 Urban, R. 203 Ursprung, H.W. 180 Valone, T.J. 36 van de Kragt, A.J.C. 200 van der Dennen, J.M.G. 109 van Winden, F. 198 Vine, I. 199 Vining, D.R. 37, 38 Vogel, C. 109 Voland, E. 128, 130, 131 Voland, R. 128 von Mises, L. 170 von Neumann, J. 183 Wade, M.J. 26 Walker, J.R. 195 Walker, L.E. 32 Wallace, A.R. 4 Waltz, K.N. 108, 196 Wamecke, A.M. 209 Warren, J.H. 32 Washbum, S.L. 100 Wason, P.C. 83, 86, 90 Wasser, S.K. 127 Webb, M.C. 108 Webley, P. 180 Webster, D. 107 Weise, P. 178 Weiss, G.H. 27 Welham, C.V.J. 138 West, E.G. 173 West, K.D. 193 Westermarck, E.A. 138 Westwood, N.J. 48 White, B.B. 203 Whiten, A. 110, 111 Wilkinson, G.S. 87 Willard, D.E. 130 Willhoite, F.H. 109 Williams, G.C. 7, 8, 11, 15, 25, 30, 38, 47, 50, 62, 127, 211 Williams, M.B. 33

256

Author Index

Wilson, D.S. 26, 27 Wilson, E.O. 26, 36, 44, 104, 213, 215 Wilson, ;.1. 4, 40, 41, 45, 48, 51, 52, 73, 123-127, 129-133, 140, 212, 216, 225, 228 Winterhalder, B. 180 Witt, U. 180 Wittenberger, J.F. 40 Wolf, A.P. 138 Wolfgang, M.E. 216, 217 Wong, Y. 109 Wright, H.T. 107 Wright, S. 17 Wynn Edwards, V.C. 24 Wynn, T. 100 Yachanin, S.A. 86 Zeckhauser, R. 187, 197 Zuckerrnan, M . 126 Zuk, M. 11, 12

Selected Bibliography Alexander, Richard D., and D.W. Tinkle. 'A Comparative Book Review of On Aggression by Konrad Lorenz and The Territorialinitiative by Robert Ardrey' Bioscience 18 (1968): 245-248. Alexander, Richard D. 'The Search for an Evo1utionary Philosophy of Man' Proceedings of the Royal Society of Victoria, Melboume 84(1) (12 May 1971): 99-119. Alexander, Richard D. 'The Evolution of Social Behavior' Annual Review of Ecology and Systematics 5 (1974): 325-383. Alexander, Richard D. 'The Search for a General Theory of Behavior' Behavioral Science 20 (1975): 77-100. Alexander, Richard D. 'Natural Selection and the Analysis of Human Sociality' in C.E. Gaulden (ed.), Changing Scenes in the Natural Sciences, pp. 283-337. Bicentennial Symposium Monograph. Philadelphia Academy of Natural Science, Special Publication 12, 1977. Alexander, Richard D., and Gerald Borgia. 'Group Selection, Altruism, and the Levels of Organisation of Life' Annual Review of Ecology and Systematics 9 (1978): 449-474. Alexander, Richard D., and Kathenne M. Noonan. 'Concealment of Ovulation, Parental Care, and Human Social Evolution' in Napoleon A. Chagnon and William G. Irons (eds.), Evolutionary Biology and Human Social Behavior: An Anthropological Perspective, pp. 436-453. North Sciutate, MA: Duxbury Press, 1979. Alexander, Richard D. Darwinism and Human Affairs. Seanle, WA: University of Washington Press, 1979. Alexander, Richard D., John L. Hoogland, Richard D. Howard, Kathenne M. Noonan, and Paul W. Sherman. 'Sexual Dimorphisms and Breeding Systems in Pinnipeds, Ungulates, Primates, and Humans' in Napoleon A. Chagnon and William G. Irons (eds.), Evolutionary Biology and Human Social Behavior: An Anthropological Perspective, pp. 402-435. North Scituate, MA: Duxbury Press, 1979. Alexander, Richard D. 'Genes, Consciousness, and Behavior Theory' inS. Koch and D.E. Leary (eds.), A Century of Psychology as Science, pp. 783-802. New York: McGraw Hili, 1985. Alexander, Richard D. 'Biology and Law' Ethology and Sociobiology 7(3/4) (1986): 167-173. Alexander, Richard D. The Biology of Moral Systems. Foundations of Human Behavior Senes. Hawthome, NY: Aldine de Gruyter, 1987. Alexander, Richard D. 'Evolutionary Approaches to Human Behavior: What does the Future Hold?' in Laura Betzig, Monique Borgerhoff Mulder, and Paul Turke (eds.), Human Reproductive Behaviour: A Darwinian Perspective, pp. 317-341. Cambndge: Cambndge University Press, 1988. 17 Elworthy

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