On remembering, forgetting, and understanding sentences: A study of the deep structure hypothesis 9783111351575, 9783110996869

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JANUA

LINGUARUM

STUDIA M E M O R I A E N I C O L A I VAN WUK D E D I C A T A edenda curai C. H. VAN SCHOONEVELD Indiana University

Series Minor,

170

ON REMEMBERING, FORGETTING, AND UNDERSTANDING SENTENCES

A Study of the Deep Structure Hypothesis

by ERIC WANNER

1974

MOUTON THE HAGUE • PARIS

O Copyright 1974 in The Netherlands Mouton &. Co .N.V., Publishers, The Hague No part of this book may be translated or reproduced in any form, by print, photoprint, microfilm, or any other means, without written permission from the publishers

LIBRARY OF CONGRESS CATALOG CARD NUMBER: 73-84695

Printed in The Netherlands

PREFACE

The deep structure hypothesis is hardly new. Variants have been advanced in the 17th century by the Port Royal grammarians, in the 18th century by the encyclopedist Du Marsais, and in the 19th century by Wilhelm Wundt, the founding father of experimental psychology. In its simplest terms the deep structure hypothesis states that the semantic relations among the elements in a sentence are not expressed directly in the physical arrangements among its words. It follows as a kind of psychological corollary, that the listener cannot apprehend the semantic relations of a sentence directly from its superficial organization. Instead he must determine some abstract representation of the sentence which displays its semantic relationships in a uniform way. It is well known that the modern revival of the deep structure hypothesis is a direct result of Chomsky's development of transformational grammar. By showing that it is possible to produce an entirely explicit set of rules which relate the superficial organization of any sentence to an abstract form which displays semantically relevant grammatical relationships, such as the logical subject and logical object of a sentence, Chomsky removed much of the vagueness which had plagued earlier versions of the deep structure hypothesis. From here it was a short step to the notion that the listener actually applies some mental equivalent of the transformational rules to obtain the deep structure specified by the grammar. In 1967-1968, when the research reported here was conducted, the evidence bearing upon this hypothesis was in a rather inconclusive state from which it has not yet fully emerged. At that time (and indeed to date) efforts to demonstrate that the listener tacitly applies transformations during comprehension had been either ambiguous or unsuccessful. On the other hand, there was rather solid evidence that the listener's long term memory of a sentence was quite abstract; and it seemed a very plausible guess that this abstraction was achieved during compre-

VI

PREFACE

hension. Moreover, Blumenthal had recently obtained evidence which was consistent with the notion that the long term memory trace of a sentence was structured according to the basic grammatical relations specified in deep structure. So at the time, our working version of the deep structure hypothesis was that the deep structure specified by the grammar is recovered during comprehension, although not by means of the transformational rules. Chapter 1 presents the detailed justification of this hypothesis. The studies reported in succeeding chapters were directed towards what appeared to be three gaps in our working hypothesis. First, despite Blumenthal's important results, there was a real shortage of evidence that the memory trace for a sentence was organized in ways which are unique to deep structure. Hence we undertook the experiment reported in Chapter 2 which examines the resemblance between the memory trace and a unique feature of deep structure, namely, its propositional form. Second, if an abstract representation of the meaning of a sentence is achieved during comprehension, as we supposed, then evidence of that abstraction should be available immediately after comprehension. All studies of immediate recall for sentences, however, had revealed that a great deal of information about the superficial form of a sentence was retained immediately after comprehension, certainly more information about form than we could account for on the grounds that it might be required by whatever computations determine deep structure. Thus in Chapter 3, we report an experiment which explores the possibility that tests of immediate recall overestimate the amount of superficial information about sentence form which is retained in normal comprehension, when there is no requirement to recall. Finally, if deep structure is recovered during comprehension, but not by means of transformations, it remains to say what kinds of psychological operations are involved. Chapter 4 contains a speculative effort to do just that. In retrospect, it becomes possible to see that the final effects of some of the work reported here may not lie in the directions anticipated at the outset. To take one example, in Chapter 2, having obtained some evidence that the long term trace of a sentence has propositional structure, we found an explanation for this phenomenon in the possibility that propositional structure is carried over

PREFACE

VII

from comprehension into a mnemonic representation of the meaning of the sentence which may itself be somewhat deeper (i.e. more abstract) than the deep structure specified by Chomsky. This is a possibility which is now being thoroughly explored in studies of long term linguistic memory, some of which now raise questions about the proper account of the results we have observed.1 This monograph is substantially the same as the doctoral dissertation which I submitted under the same title to the Department of Social Relations of Harvard University in 1969. The major exception falls in Chapter 3 where three experiments which did not appear in the original dissertation are reported (see sections 3.2 to 3.4). The effect of these experiments is to decrease considerably our previous estimate of the amount of information about the superficial form of the sentence which the listener retains in normal comprehension. In 1968, we knew that superficial information of this sort was not retained after 44 syllables of intervening material. We know now that such information can disappear after as few as 16 syllables. This result is interesting because it places rather severe limits on the amount of information about form which a psychologically suitable model of comprehension can require. It goes without saying that many people have influenced the course this work has taken. Many others have provided valuable technical assistance. Special thanks however, are due Roger Brown, Arthur Blumenthal, Edward Kelly, David McNeill, and Donald Olivier who read early versions of the manuscript and offered many helpful comments. Thanks also go to Miss Susan Duffy who helped run the experiments reported in Chapter 3 and to Mrs. Elizabeth Burnham and Mrs. Antonia Humphries who typed the manuscript. Cambridge, Mass. September, 1972

Eric Wanner

l See, for example, A.M. Lesgold, "Pronominalization: A device for unifying sentences in memory", Journal of Verbal Learning and Verbal Behavior, 11 (1972), p. 316-323.

CONTENTS

Preface

V

List of Tables

XI

List of Figures

XIII

1.

The Comprehension Problem 1.1. 1.2. 1.3. 1.4. 1.5.

1

Psychological Models 4 Incorporation Models 8 The Empirical Status of Transformational Models . . 21 The Transformational Hypothesis 24 The Deep Structure Hypothesis 30

2.

On Remembering Sentences 2.1. Prompted Recall and Deep Structure 2.2. Experimental Method 2.2.1. Procedure 2.2.2. Subjects 2.2.3. Sentences and Prompts 2.3. Free Recall and a Measure of Prompt Effectiveness 2.4. Prompted Recall 2.5. Artifacts 2.6. Explanations

3.

On Forgetting Sentences 3.1. Experiment 1 3.1.1. Procedure 3.1.2. Design 3.1.3. Subjects 3.1.4. Results 3.1.5. Response Bias

37 37 47 47 48 48 . 57 61 66 72 82 87 87 88 92 92 95

X

4.

CONTENTS

3.2. Experiment 2 3.2.1. Procedure 3.2.2. Design 3.2.3. Subjects 3.2.4. Results 3.3. Experiment 3 3.3.1. Design 3.3.2. Procedure 3.3.3. Subjects 3.3.4. Results 3.4. Experiment 4 3.4.1. Design 3.4.2. Procedure 3.4.3. Subjects 3.4.4. Results 3.5. Conclusions and Qualifications

98 100 101 102 103 104 105 106 107 107 107 109 110 110 110 Ill

On Understanding Sentences 4.1. Comprehension Mechanisms 4.2. On Evidence for the Lexical Model

114 114 131

Bibliography

140

Appendix A

147

Appendix B

155

Index

159

LIST OF TABLES

1.1

The Transformational Derivations of Sentences (12) and (13)

18

1.2

Re-analysis of Mehler's Data: Recall Errors as a Function of Deep, Surface, and Semantic Similarity to the Stimulus Sentence 29

2.1

Summary of Blumenthal's Prompted Recall Results

2.2

List of the Sentences Used in the Prompted Recall Experiment

54

Basic Experimental Design for the Prompted Recall Experiment .'

56

2.3

.

.

42

2.4

Final Design of the Prompted Recall Experiment

2.5

Mean Number of Sentences Correctly Remembered During Free Recall

58

Mean Relative Prompt Success (RPS) as a Function of Prompt Type and Verb Type

62

2.6

.

. . .

.56

2.7

Mean Number of Prompt Words Assigned to Their Original Sentences as a Function of Prompt Type and Verb Type . . 69

2.8

The Strength of Association ( object noun

easy > eager

Explanations Relational Deep Proposition Inclusiveness Hypothesis Hypothesis subject equals topic subject more inclusively related in active sentence than object object more inclusively related than adjective

object in 2 propositions; adjective in 1 proposition

object equals topic in active sentence, thus cancelling inclusiveness effect

subject and object both in one proposition

John in eager sentence more inclusively related than in easy sentence

John in 2 propositions in eager sentence: in 1 proposition in easy sentence

easy more inclusively related than eager

No explanation

matical analysis equivalent either to John is eager to please or John is easy to please were used. One group of subjects received the noun as prompt, another the adjective. In both types of sentence, the noun is the topic, but recall from Chapter 1 that John is the subject of the Journal of Verbal Learning and Verbal Behavior, 6 (1967), pp. 674-676 for an account of the last experiment in Blumenthal's series. Note that we have eliminated from this review one study in Blumenthal's series which purports to supply evidence for the relational inclusiveness hypothesis but which Blumenthal himself points out is open to an explanation based on surface structure features of the sentence. For the study in question see A. Blumenthal "Prompted recall of sentences", Journal of Verbal Learning and Verbal Behavior, 6 (1967), pp. 203206.

ON REMEMBERING SENTENCES

43

entire eager sentence but only the object of please in the easy sentence. Thus when Blumenthal found that the noun was a more effective prompt in the eager sentences, he attributed the effect to relational inclusiveness. However, consideration of the deep phrase markers of the two types of sentences (see Chapter 1, p. 17) reveals that the initial noun is also involved in one more deep proposition in the eager sentence. Therefore this result does not rule out the proposition hypothesis. Prompting with the adjectives, however, revealed that the easy type sentence modifiers were more effective memory aids than the eager type noun phrase modifiers. This result is in line with the relational inclusiveness hypothesis but fails to receive any explanation on the basis of deep propositions since both types of adjectives are involved in only one basic sentence. As Table 2.1 indicates, this bit of evidence is the only result which distinguishes the two accounts of prompt effectiveness. For just that reason it is worth some attention. Blumenthal agrees that sentence modifiers and nominal modifiers are members of distinct lexical categories. But it is difficult to base an explanation of prompt effectiveness on lexical class. In fact, Blumenthal and Boakes carried out a paired associate test in which the adjectives and nouns from the original sentences comprised the input pairs. 12 When the adjectives were used to elicit an associate, no difference, in terms of correct recall of the paired noun, was found between the two types of adjectives. Thus Blumenthal appears to have made a fairly strong case that the prompting differences found with the adjectives are due to the grammatical relations which obtain only when they are incorporated in sentences. It should be noted, however, that Blumenthal's test employs 20 unique adjectives, 10 of each lexical type, each one inserted in an entirely distinct sentence. It is at least possible then, that these adjectives and sentences were inadvertently selected in such a way that each adjective had a slightly different degree of semantic or pragmatic 'fit' to the entire set of sentences. To illustrate the problem, consider three of Blumenthal's original sentences: (21) Customers are easy to please. (22) Rudeness is quick to offend. (23) Gamblers are desperate to win. 12

A. Blumenthal and R. Boakes, "Prompted recall of sentences".

44

ON REMEMBERING SENTENCES

Notice that on purely semantic grounds, quick can be substituted in either of the other sentences, but desperate can only be substituted in (21) and easy cannot be substituted anywhere. The reasons for the incompatibilities are quite varied: easy cannot be substituted in (23) because the verb win takes few if any human objects (*We won the gamblers)-, desperate will not fit into (22) because it can only modify animate or action nouns and so on. On pragmatic grounds it may well seem unlikely that customers are either quick or desperate to please but this sort of incompatibility is more difficult to determine. Whatever the precise degree of 'fit' for any adjective, however, the point is that it may be variable over the set of adjectives. And it seems reasonable that the smaller the set of compatible sentences for any prompt adjective, the easier it would be for a subject who had forgotten which sentence included the prompt to guess correctly by chance alone. Therefore it is possible that the easy adjectives are better prompts for reasons which are unique to the set of sentences Blumenthal used. To assess this possibility, a simple test was constructed which is analogous to the prompted recall format with the single exception that no recall is involved. 13 The subject was presented with a list of Blumenthal and Boakes' original sentences with a blank in place of each adjective. He was then asked to leaf through a randomized deck of index cards, each of which had one adjective and a number printed on it. For each card, the subject's task was to write the number next to the sentence frame which he felt the adjective fit into most appropriately. The subject was not allowed to assign more than one adjective to any sentence, to change any of his answers, or to look ahead in the deck of cards. The full set of instructions used is given in Appendix A, part 1. Of the twelve subjects tested in this way, ten assigned more sentence modifiers than nominal modifiers to their original sentence frames (p = .038 by a two-tailed sign test). On the average, 3.25 of the ten easy adjectives were assigned correctly, as compared to 2.0 of the eager adjectives. Moreover, each of the ten noun phrase modifiers were assigned to an average of 5.6 different frames while the sentence modifiers averaged only 4.9 frames. Taking these means as a rough estimate of the number of sentences with which each adjective was subjectively compatible, it appears that the sentence modifiers fit into is

I am indebted to P. Smith for suggesting this type of test.

ON REMEMBERING SENTENCES

45

a slightly smaller set of frames and were therefore easier to guess in this task. Thus it may be this compatibility factor which accounts for the superiority of the sentence modifiers when used as prompts. It is important to emphasize that the differences found in degree of compatibility between these two sets of adjectives are not related to the lexical categories which distinguish them. Both sentence modifiers and noun phrase modifiers interact semantically with both the noun phrase and the non-finite verb in the sentences which Blumenthal used. This can be demonstrated by the fact that, with either type of adjective, compatibility can be destroyed by altering either of the residual terms in the sentence. Again we illustrate with two of Blumenthal's sentences. 14 Sentence Modifier: (24) Rowers are delightful to receive. *?Bombs are delightful to receive. *? Flowers are delightful to destroy. Nominal Modifier: (25) Soldiers are impatient to attack. *?Grandmothers are impatient to attack. *?Soldiers are impatient to suffer. It follows that the relational differences between sentence and noun phrase modifiers in sentences of this type do not in any way account for the results of the guessing test. On the contrary, the results of the guessing test suggest that the semantic and pragmatic associations elicited by these sentences combined to make the ten sentence modifying adjectives easier to place in their original frame. Therefore the superiority of these adjectives as prompts may well be entirely unrelated to their syntactic function. If so, then the easy-eager evidence for the relational inclusiveness hypothesis evaporates, and we are left with no results which choose between the relational inclusiveness and the deep propositions hypotheses. It is difficult, if not impossible to find any strong a priori grounds which distinguish between the two positions. However, there is a sense 14 Wc use the designation *? instead of * to indicate that these sentences are pragmatically unacceptable rather than syntactically informed or semantically anomalous. Just this sort of incompatibility appears to have played a major role in the subject's choices in the guessing task.

46

ON REMEMBERING SENTENCES

in which the propositions hypothesis has more interesting consequences for the comprehension problem. As argued extensively in Chapter 1, the basic grammatical relations must be determined during comprehension in order to support semantic interpretation. Therefore, the relational inclusiveness hypothesis, even if true, does not add new information concerning the process of comprehension. At best, it would only indicate that the grammatical relations realized during comprehension have a mnemonic effect. The deep propositions hypothesis, however, makes a claim about a unique feature of the deep phrase marker, which is in no way necessary to the process of comprehension. To secure this point, consider the fact that the atomic sentences defined by the base component of the grammar display considerably more information than the listener would minimally require in order to determine the semantically relevant grammatical relations. Thus in sentences like (26) John's drinking astounded Marcia. (27) John's sonata amused Marcia. the listener must be able to determine that some relation (call it the possessive) holds between John and the gerund drinking in (26) and the noun sonata in (27). He must also know that these relations do not hold between Marcia and the gerund or noun. However, he may or may not analyse the possessive relation as equivalent to the subjectpredicate relation in (28) or the subject-object relation in (29). But just this claim is implicit in the notion that the deep propositions are computed in the course of comprehension if we accept Lees' analysis in which genitives arise from deep sentences such as: 15

¡

(28) John drank. wrote )

played > a sonata, has ) There is then nothing necessary about the claim that deep propositions are determined during comprehension. As a consequence, any evidence that deep propositions correspond to the organization of is

R.B. Lees, "The grammar of English nominalizations".

ON REMEMBERING SENTENCES

47

the memory for sentences, is consistent with a non-trivial hypothesis about comprehension. Of course, facts about memory do not require conclusions about comprehension. But at least any evidence indicating that propositions are mnemonically relevant puts the burden of explaining such relevance upon a theory of comprehension which claims that deep propositions are not realized in the course of understanding a sentence. Therefore we turn now to an experiment designed to compare the relational inclusiveness account of prompt word effectiveness with the notion that the degree to which a prompt word aids recall is a function of the number of deep propositions in which it is involved.

2.2.

E X P E R I M E N T A L METHOD

2.2.1

Procedure

The experimental format used in the study to be described follows Blumenthal and Boakes with minor variations.16 Subjects were told that they would be tested on their ability to recall sentences and that they would be given ample rehearsal. Appendix A, part 2, reproduces these instructions. In the first rehearsal sequence, the subject was read each sentence, asked to paraphrase it and incorporate it in a two or three sentence story of his own invention. This procedure was used to insure that the subject processed the sentence fully. Requiring the subject to invent his own story, unlike previous procedures where the story was supplied to the subject, provides a check on the way the subject has interpreted the sentence and consigns all differences due to vividness of the story to within subject variation. In the second and third rehearsal sessions, the subject was simply asked to repeat each sentence as read. This was done in order to minimize stylistic errors which occur frequently if the superficial arrangements of the sentence are not well practiced. After the final rehearsal session, the subject was given four minutes to recall as many sentences as he could. Only at this point was the subject assigned randomly to one of the prompting conditions whereupon he was read a single prompt word from each sentence and given ten seconds to respond. Both the prompts and the 16

A. Blumenthal and R. Boakes, "Prompted recall of sentences".

48

ON REMEMBERING SENTENCES

sentences in each rehearsal session were presented in random order. Subjects' responses in the free and prompted recall tasks were recorded on tape and scored later. A sentence was counted as correct only if it was recalled perfectly. Performance on the free recall task was used as a base rate against which the effectiveness of the prompt words was evaluated. 2.2.2.

Subjects

Eighty Harvard Summer School students (19 male; 61 female; average age 20.4 years) were paid to participate. 2.2.3.

Sentences and Prompts

Since the relational inclusiveness and deep proposition accounts of promt effectiveness are not mutually exclusive, the optimal comparison would be based on a test of each effect with the other controlled. Additionally, confounding factors such as the serial position, lexical category, and topic-comment status of the prompt should be held constant. Blumenthal managed to control all these factors for the noun prompts in easy-eager sentences. Therefore it should be a simple matter to go one step further and find sentences where the prepositional involvement of the prompt is also controlled, but it is not. A lengthy search and consultation with several linguists failed to yield any sentences where relational inclusiveness could be varied while holding propositional involvement and all other factors constant. However, the reverse is possible. Sentences can be constructed such that a prompt word varies in propositional involvement but not in relational inclusiveness. Consider the following pair: (30) The detective was asked to cease drinking. (31) The detective was asked to prevent drinking. The only superfical distinction between (30) and (31) is the nature of the non-finite verb. Intuitively, however, it is clear that in (30) it is the detective who is, or has been, drinking while in (31) it must be someone else. The semantic difference is reflected at the level of deep structure. Cease and prevent verbs can be distinguished according to the types of deep structure in which they can participate. In general,

ON REMEMBERING SENTENCES

49

cease is intransitive in the sense that it will not take a noun phrase object in deep structure. However, as in (30), cease can take a sentential complement, but in this case the subject noun phrase of the constituent sentence must be identical to the matrix subject. Prevent is distinct from cease in two ways at the deep level: first it is transitive insofar as it takes complex noun phrase objects, and second, it does not require identity between matrix and constituent elements. 17 In particular then, (30) and (31), despite superficial similarity, have distinct deep phrase markers which can be represented roughly as follows: for (30) s

the detective

drink

for (31) NP \

I

Someone

VP-

IY

w / \

ask the detective

17 See P. Rosenbaum, The Grammar of English Complement for details.

Constructions,

50

ON REMEMBERING SENTENCES

Observe that in each sentence detective is the object of the entire predicate

string:

asked...

to! J drinking. This string I prevent I measures the inclusiveness of the relations which obtain for detective and is constant over the two sentences. But in (30) detective is involved in three deep propositions, one more than in (31). Therefore according to the propositions hypothesis, but not according to the relational inclusiveness hypothesis, detective nouns should be a better aid to recall in sentences with cease type verbs. A small pilot study was run using ten sentences of each type. The detective nouns were given as prompts. Seven of the ten subjects tested recalled more cease than prevent sentences with two subjects showing no difference (p = .05 Wilcoxon sign-rank, one-tailed). Despite the encouraging result there were several problems. First, although all the verbs employed in the asked position were different, they were all, of necessity, verbs of interpersonal communication which comprise a semantically homogeneous set. Subjects had difficulty recalling these verbs correctly for reasons which are probably entirely independent of prompting. Therefore, synonymous verbs in the asked position had to be counted as correct when the responses were scored. Second, the problem of variable compatibility of prompts and sentence frames applies to this data as well as to Blumenthal's work, since here again twenty distinct prompt words were inserted in twenty different frames. The final and most subtle problem arises from the fact that the deep structure for (31) has two indefinite noun phrases (represented above by the morpheme someone) while (30) has only one. The extra someone stems from the unnamed agent who is doing the drinking. It is conceivable that when subjects are exposed to sentences with understood indefinites in deep structure, they tacitly supply a nominal expression for the indefinites. If so, then (31) might have one more nominal term associated with it in memory than (30), and this could provide additional interference during the retrieval process initiated by the prompt. To avoid the difficulties observed in the pilot, a new set of test sentences was constructed according to the following format: f C63S6 \ (32) The governor asked the detective to j prevent j drinking.

ON REMEMBERING SENTENCES

51

Figures 2.1. and 2.2. provide the deep phrase markers for each version of (32) and Table 2.2. lists the full set of sentences used in the test. Notice that no word was repeated in any sentence with the exception of the first verb which was asked in every case, thus eliminating the problems which occurred with the first verb in the pilot. In order to reduce the compatibility problem, pairs of sentences were constructed such that a given pair of cease and prevent type verbs could be inserted in the non-finite position of either sentence. This made it possible to administer two different versions of the test sentences (Forms I and II in Table 2.2) which are mirror images of each other in the sense that those ten sentences which appear with cease verbs in Form I, appear with prevent verbs in Form II. Therefore any differences in prompt to sentence frame compatibility, which might be positively correlated with prepositional involvement in (say) Form I, would have to be negatively correlated with propositional involvement in Form II. Thus spurious prompt effects should show up as interactions with Test Form. It should be pointed out, however, that this procedure does not control for those incompatibilities which might obtain between the prompts and the non-finite verbs themselves, and we will return to this possibility when we consider alternative explanations of the results observed. Finally, notice that the addition of the governor noun in (31) allows a check on the possibility that the superiority of the detective prompts in cease sentence is due to interference by indefinites. If such interference occurs, then the governor prompts should also show differences in effectiveness across the two sentence types. But, as indicated in Figures 2.1 and 2.2 the governor noun is involved in only a single deep proposition irrespective of the nature of the non-finite verb. Therefore, according to the propositions hypothesis, more cease than prevent sentences should be recalled only when detective nouns are used as prompts. In what follows we will refer to the detective nouns as the experimental prompts, and to the governor nouns as the control prompts. To test these predictions, four groups of ten subjects each were run. Each group was exposed to ten sentences with cease type verbs and ten with prevent type verbs. Two groups received the experimental prompts; two received the control prompts. Two groups were administered the sentences in Form I; two received Form II. This results in the three-way factorial design with repeated measures on one factor which is summarized in Table 2.3, where the predictions made by the

52

ON REMEMBERING SENTENCES FIGURE 2.1 The Deep Structure for a cease Sentence (follows Rosenbaum)

the

governor

Prompts detective:

therefore:

-

object of asked subject of cease (drinking} subject of drinking

-

detective is related to the predicate string asked. . . to cease drinking which is encompassed by this relation.

-

detective is also a constituent of three deep structure sentences.

governor:

-

subject of asked the detective to cease drinking

therefore:

-

governor is related to the predicate stringateci the detective to cease drinking which is encompassed by this relation.

-

governor is also the constituent of only one deep structure proposition.

Transformational Derivation: 1st Cycle: Complementizer placement Equi NP deletion Complementizer deletion

2nd Cycle: 3rd Cycle: Complementizer Tense and number placement agreement It replacement Equi NP deletion Complementizer deletion

ON REMEMBERING SENTENCES

53

FIGURE 2.2 The Deep Structure for a prevent Sentence (follows Rosenbaum)

detective

prevent

it

*»

yp

Nf

I

someone

Prompts detective: •

I

drink

object of asked subject of prevent detective is related to the predicate string asked. . . to prevent (drinking) which is encompassed by the relation.

therefore:

detective is also a constituent of only 2 deep structure propositions. governor:

-

therefore:

- governor is related to the predicate string asked the detective to cease drinking. -

subject of asked the detective to cease drinking.

governor is also a constituent of only one deep structure proposition.

Transformational Derivation: 1st Cycle: Complementizer placement It replacement Complementizer deletion

2nd Cycle: Complementizer placement It replacement Equi NP deletion. Indefinite deletion Complementizer deletion

3rd Cycle: Tense and number assignment

54

ON REMEMBERING SENTENCES TABLE 2.2 List of the Sentences Used in the Prompted Recall Experiment

Form /: Sentences with cease verbs 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

The boss asked the foieman to continue stalling. The chairman asked the executive to resume borrowing. The commissioner asked the judge to swear off gambling. The doctor asked the nurse to finish smoking. The governor asked the detective to cease drinking. The mathematician asked the teacher to begin reasoning. The owner asked the lifeguard to practice diving. The peasant asked the landlord to try farming. The proctor asked the student to refrain from cheating. The rebels asked the girls to fake rioting.

Sentences with prevent verbs 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

The ambassador asked the guide to permit travelling. The coach asked the captain to forbid wrestling. The dignitary asked the lieutenant to prevent yelling. The director asked the actor to provoke arguing. The guard asked the inmate to expose plotting. The manager asked the waiter to overlook pilfering. The politician asked the king to require voting. The prophet asked the disciple to inspire praying. The salesman asked the merchant to discourage buying. The warden asked the ranger to prohibit hunting.

Form II: Sentences with cease verbs 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

The The The The The The The The The The

ambassador asked the guide to resume travelling. coach asked the captain to practice wrestling. dignitary asked the lieutenant to cease yelling. director asked the actor to fake arguing. guard asked the inmate to refrain from plotting. manager asked the waiter to swear off pilfering. politician asked the king to try voting. prophet asked the disciple to begin praying. salesman asked the merchant to continue buying. warden asked the ranger to finish hunting.

55

ON REMEMBERING SENTENCES TABLE 2.2

-

Continued.

Sentences with prevent verbs 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

The The The The The The The The The The

boss asked the foreman to discourage stalling. chairman asked the executive to permit borrowing. commissioner asked the judge to overlook gambling. doctor asked the nurse to prohibit smoking. governor asked the detective to prevent drinking. mathematician asked the teacher to inspire reasoning. owner asked the lifeguard to forbid diving. peasant asked the landlord to require farming. proctor asked the student to expose cheating. rebels asked the girls to provoke rioting.

deep propositions hypothesis are indicated by entering the degree of prepositional involvement which obtains in each condition. Additionally, Table 2.3 displays the fact that the deep propositions hypothesis also predicts that in both cease and prevent sentences, the experimental prompts should be superior to the control prompts. This follows because detective is involved in either two or three deep sentences, while governor is never involved in more than one. The relational inclusiveness hypothesis predicts just the reverse, however, since governor is the subject of the highest sentence in the deep phrase marker and is related directly to the rest of the sentence. As indicated in Figures 2.1 and 2.2, detective is only the object of the highest sentence and therefore bears no direct relation to the subject, governor. These differential predictions cannot be tested with the design as it now stands because the experimental and control prompts also differ in topic-comment status. Governor, as the initial noun phrase, is of course the topic and detective is a part of the comment. Both the competing deep structure hypothesis and the topic-comment notion can be tested independently, however, simply by replicating the entire study outlined in Table 2.3 on four new groups whose treatment does not differ from that of the first four with the single exception that they receive passivized versions of the original sentences such as:

iCC dS6 ing.

1

l prevent I r

56

ON REMEMBERING SENTENCES TABLE 2.3 Basic Experiment Design for the Prompted Recall Experiment

Group

Prompt Type

1 2 3 4

Experimental Experimental Control Control

Test Form

cease

Verb Type prevent

3a 3 1 1

I II I II

2 2 1 1

a Cell entries refer to the number of deep propositions in which the prompt word is involved in each case.

Passivizing changes none o f the essential features of the deep phrase marker, so all previous predictions hold. The only effect is to reverse the surface order of the t w o prompts, thus reversing their topiccomment status, and thereby permitting comparison o f both experimental and control prompts as topic and comment. Table 2.4 summarizes the resulting four-way design as well as the relevant predictions for each hypothetical account o f prompt effectiveness. TABLE 2.4 Final Design of the Prompted Recall Experiment Group

Prompt Position

Prompt Type

Test Form

1 2 3 4 5 6 7 8

Topic Topic Topic Topic Comment Comment Comment Comment

Experimental Experimental Control Control Experimental Experimental Control Control

I II I II I II I II

a

Verb Type cease prevent 3pa 3p 1a 1a 3a 3a IP IP

2p 2p 1a 1a 2a 2a 1P IP

The first cell entry again designates the degree of propositional involvement of the prompt. The second denotes whether the sentences used were active (a) or passive (p). Notice that the Topic-Comment factor is confounded with a Prompt Type X Active-Passive interaction but this possible source of prompted recall differences seems unlikely enough to be safely ignored.

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57

Predictions: Propositions Hypothesis: (1) More cease than prevent sentences recalled for experimental prompts. (2) No cease - prevent differences for control prompts. (3) Experimental prompts more effective than control prompts. Interference Hypothesis: (1) More cease than prevent sentences recalled for both experimental and control prompts. Relational Inclusiveness Hypothesis: (1) Control prompts more effective than experimental prompts. Topic-Comment Hypothesis: (1) Prompts in initial position more effective than prompts in secondary position.

2.3.

F R E E R E C A L L AND A M E A S U R E O F PROMPT EFFECTIVENESS

It should be clear that the gross number of sentences recalled when prompts are given is not a satisfactory measure of prompt effectiveness. In particular, we do not want to credit the prompt with retrieving a sentence which might have been recalled correctly without the aid of the prompt. Therefore some means of adjusting the number of sentences recalled with prompts (Np) by the number of sentences recalled without prompts in the free recall session ( N f ) is required. Blumenthal and Boakes used simple subtraction (Np—Nf) as a method of adjustment, but this procedure has several disadvantages.18 First, it combines two substantively distinct types of events: a subject may achieve an (Np—Nf) score of (say) 2 by recalling two sentences with prompts that he did not recall without prompts, or he may recall three new sentences with prompts but fail to retrieve with a prompt a sentence he had remembered correctly at free recall. It is not obvious that these prompt failures should count against the retrieving power of a prompt word since most often they are not simple failures to recall as much as confusions based upon some relation, usually semantic, between the prompt and the set of input sentences. A rather bizarre example was supplied by one subject who had correctly recalled the sentence The prophet asked the disciple to inspire praying during free recall but when given the prompt prophet responded The 18

A. Blumenthal and R. Boakes, "Prompted recall of sentences".

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chairman asked the executive to make a profit, a response similar to a sentence originally presented as The chairman asked the executive to resume borrowing. Whatever the exact reason for such prompt failures, it seems clear that they are more a function of the idiosyncratic relations between the particular prompts and sentences involved in the test than of the syntactic properties of prompts. Prompt failures were not frequent enough in our data to provide a real problem. However, (Np-Nj) was discarded on more serious grounds. TABLE 2.5 Mean Number of Sentences Correctly Remembered During Free Recall ( N f ) Prompt Position:

Prompt Type:

Fal,72 P 1.21 -

Topic 3.44

Comment 3.88

Experimental 3.46

Control 3.85

.95 -

I 3.46

II 3.85

.95 -

cease 3.88

prevent 3.44

3.84 .10

Active

Passive

3.65

3.66

Form:

Verb Type:

Sentence Type (Prompt Position X Prompt Type)

.00 -

a

Unless noted otherwise, the F ratios reported are from a four-way analysis of variance with repeated measure on one factor (Verb Type) outlined in Table 2. Hartley's F m a x test was used to assess the homogeneity of within cells variance for every analysis reported and in no case was the null of homogeneity rejected. The Prompt Position X Prompt Type interaction is listed here to show that passive sentences were not more difficult to recall than actives. In general interactions will be ignored unless significant.

Notice that (Np-Nf) has a maximum value which is a joint function of Nf and the total number of sentences presented (Nt). Thus (Np-Nf) max. = (Nt-Nf).

If Nf is relatively constant over treatment

combinations as in Blumenthal's data, the possibility of a ceiling effect is of little consequence. However, as shown in Table 2.5, the mean Nf varies here by as much as almost half a sentence over con-

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ditions, although only one of these differences approaches significance. Moreover when (Np-Nf) is plotted by Nf a fairly clear inverted U-shaped function results. The obvious way to deal with this ceiling effect is to divide (Np-Nf) by (Nt-Nf) thus expressing the improvement due to the prompts as a fraction of the maximum possible improvement. But this correction proves to be complex for a measure like (Np-Nf) which has a minimum value (or -Nf when Np = O) as well as a maximum. To simplify matters, we ignored the prompt failures described earlier and measured prompt effectiveness by the number of sentences which were not remembered during free recall but which WERE recalled when the prompt was provided. 19 The number of these prompt successes (Nps) was then divided by the number of sentences not recalled during free recall (NrNf) (or as we will now designate it N.f) to correct for the ceiling effect. It is not difficult to show that the resulting measure (Nps/N.f) is simply the maximum likelihood estimator of the probability that a given subject will successfully recall with the aid of a prompt a sentence which he has failed to remember at free recall. Given that

(

that a sentence is not recalled \

p

.

correctly at free recall ) = / that a sentence is recalled correctly I with a prompt and not recalled \ correctly at free recall

then

™lfR> p(-rK)

,

f*-™J = \ ] = p(PR and -FR) =Nps / Nt /

PR

p(PRl-FR)=P(

,

N.f / Nt

=Nps / N.f

19 To allay fears that data are being thrown away here in order to substantiate subsequent hypotheses, it should be mentioned that prompt failures were analyzed separately and tended to support the propositions hypothesis insofar as fewer prompt failures occurred in those conditions where the degree of propositional involvement of the prompt was highest. However, these results showed significant interactions with Test Form as should be expected if failures are primarily due to semantic confusions between prompt words and other vocabulary items in the sentences. Therefore eliminating prompt failures serves only to reduce noise in the data.

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We will call (Np S IN.f) 'relative prompt success' (or RPS) since it measures the frequency of prompt successes relative to the maximum number of such successes which could occur given a certain performance on free recall. It turns out the RPS is positively correlated with Nf (r = .41) which is probably as it should be since a subject who has a good memory or concentrates particularly well on the experimental task should be able to perform better at both free and prompted recall. However, there is another interpretation of this correlation: namely that since RPS = (Nps/N.f) and N.f = (Nt-Nf), RPS should take on higher valuesi as Nf increases and N.f consequently decreases, Nt being the constant number of sentences presented. This is a particularly insidious possibility since it implies that our measure of prompt effectiveness is artificially tied to performance on the free recall test. But notice that this interpretation is only correct if Nps is constant over the range of values which Nf assumes. If Nps tends naturally to increase with N f , but decreases with large values of Nf only because of the ceiling effect due to small Nt, then the correlation of RPS and Nf reflects only the correlation which would have occurred between Nps and Nf if no ceiling effect was operative. In fact, the data suggest that this is the appropriate interpretation of this correlation; for the correlation between Nps and Nf for those subjects who were below the median on Nf (and hence less subject to the ceiling effect) is +.27, while the correlation for those subjects above the median on Nf (and hence more subject to the ceiling effect) is -.33. Figure 2.3 displays mean Nps as a function of Nf with the two regression lines and the ceiling plotted. We conclude then, that the major reasons for the correlation between RPS and Nf are the individual differences in memory and motivation which the subjects bring to the experiment and which are reflected in both the free and prompted recall tasks. This is, of course, a rather critical conclusion which influences the interpretation of all the results based upon RPS as a measure of prompt effectiveness.

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61

Figure 2.3 Mean NpS as a Function of Nf (all 20 test sentences pooled for each subject)

2.4.

PROMPTED R E C A L L

We begin with the interference hypothesis. Recall that on this view both the experimental and control prompts should elicit more correct retrievals of cease sentences than of prevent sentences because subjects may tacitly supply prevent sentences with the unmentioned subject of the final verb. The free recall data lend some credence to this notion since as indicated in Table 2.5 slightly more cease than prevent sentences were remembered correctly. Conceivably this difference in free recall values reflects the tacit additions made to prevent sentences, although this is by no means the only explanation. 20 To check 20 Specifically, prevent sentences have one more transformation in their derivational histories than do cease sentences (see Figures 2.1 and 2.2 above). According to Miller's coding hypothesis (see Chapter 1, p. 26 above), the extra mnemonic 'footnote' due to this transformation could account for the dif-

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this possibility, the stories which the subjects invented during the first rehearsal session were coded, as they were being told, according to whether or not they included an agent other than those mentioned in the input sentence. Of the twenty sentences, seventeen elicited more such extra agents when they contained a prevent type verb than when they contained a cease verb (p .30, df = l ) . 1 3 As the MINIMAL MEMORY HYPOTHESIS predicts however, the warning DOES increase the subjects' ability to recall stylistic aspects of the input sentence: here 73% of those who received the warning correctly identified the input sentence, while only 50% of the unwarned subjects were correct ( x 2 = 2.93, p