may-june 2024 American Scientist

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Authorship rights of GENERATIVE AI

Urban green spaces reflect ENVIRONMENTAL INEQUALITY

The key to treating UTIs: URINARY MICROBIOME

AMERICAN

Scientist May–June 2024

www.americanscientist.org

Keeping Track of Satellites Each new launch increases crowding and collision risks in orbit.

A Time of Porpoise A

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AFFORD THE EXTRAORDINARY

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Volume 112 • Number 3 • May–June 2024

Feature Articles

130 From the Editors 131 Letters to the Editors 134 Spotlight Slithering robots to the rescue • Sea turtle files • Global discourse on science communication • Briefings 142 Perspective The racist legacy of urban green spaces Asia Murphy 148 Science and Engineering Values AI and responsible authorship Robert T. Pennock 154 Ethics The rights of the dead Anita Guerrini

Scientists’ Nightstand 184 Book Reviews Earth 2.0 could be just around the corner • Do you wanna dance?

160 160 Do You Know Where Your Satellite Is Tonight? Increasingly crowded orbits require transparent modeling practices and data exchange. David Finkleman 168 Discovering the Urinary Microbiome For more than a century, doctors thought urine was sterile. Now, microbiology breakthroughs are revolutionizing diagnosis and treatment of urinary tract infections. Alan J. Wolfe and Linda Brubaker

168 176 Connected Behaviors Animals use complex social networks to disseminate practices that are distinct to their geographic and cultural groups. Lee Alan Dugatkin

176

From Sigma Xi 189 Sigma Xi Today Passing the torch • Sigma Xi elections: Call for nominations • Faces of GIAR: Anne Elizabeth Thaxton and Jyoti R. Behera • IFoRE ‘24 • Distinguished Lecturers

The Cover Authorship rights of GENERATIVE AI

Urban green spaces reflect ENVIRONMENTAL INEQUALITY

The key to treating UTIs: URINARY MICROBIOME

AMERICAN

Scientist May–June 2024

www.americanscientist.org

Keeping Track of Satellites Each new launch increases crowding and collision risks in orbit.

US$5.95

A European Space Agency rocket launch in 2013 carried three satellites to orbit. Now, launches can carry dozens of small satellites at a time, quickly growing the population of devices in Earth’s orbit, which in turn increases the potential for collisions. In “Do You Know Where Your Satellite Is Tonight?” (pages 160–167), David Finkleman describes networks of ground-based observation stations, as well as data modeling techniques, that are used to try to keep track of everything in orbit around Earth and predict collisions. Finkleman also lays out why these networks and models are incomplete and their resulting collision estimates are thus largely inaccurate, and explains ways that data could be made more precise to protect valuable satellites in the future. (Cover image courtesy of ESA.)

From the Editors

Equitable Treatment

AMERICAN

Scientist www.americanscientist.org VOLUME 112, NUMBER 3

I

ing program and comn the early 1900s, petition, with some of in neighborthe awards specifically hoods across the earmarked for women. United States, One competition winreal estate covenants ner is working on systo prevent nonwhite tems that will translate buyers from purchasinformation on the ing homes in certain internet into many of neighborhoods were the Indigenous African both legal and comlanguages. mon. Although this In this issue’s Ethics overtly racist praccolumn, Anita Guerritice was outlawed in ni considers our most 1968, its effects are Caught in the Moment Photography intrinsic possession— still with us today. As Asia Murphy describes in this is- our bodies—in “The Rights of the sue’s Perspective column, “The Racist Dead” (pages 154–159). Guerrini gives Legacy of Urban Green Spaces” (pages the example of Charles Byrne, a man 142–147), neighborhoods that once had who lived in the late 1760s and who racist covenants today have a higher was 2.31 meters tall. During his life, Bypercentage of green spaces. Murphy rne earned money as an attraction, but explains that the lack of these environ- he specifically forbade his body from mental resources in a neighborhood being displayed after death. Nonethehas been found to have effects on resi- less, his body ended up in a scientific dent health and wildlife species diver- collection. Guerrini examines the ineqsity. Measures such as simply planting uities of studying or displaying human more trees in underserved neighbor- remains without explicit permission. Another aspect of equality is covered hoods will not fix these disparities, especially if such improvements increase in this issue’s Science and Engineering rents in the area and force low-income Values column. In “AI and Responsible residents out. A lot of structural chang- Authorship” (pages 148–153), Robert T. es would need to be implemented to Pennock broaches the ethical question ensure that this and many other envi- of when an artificial intelligence should ronmental inequities are corrected. receive credit as a coauthor of a scienIn this issue’s First Person column tific paper. If an AI bot is given access to (pages 138–140), Elizabeth Rasekoala raw data, analyzes it, and makes a new recounts that when she went to gradu- discovery, is that sufficient for it to rise ate school in the United Kingdom, it was above the role of a tool to the level of easier for someone from Africa to attend a collaborator? Pennock argues that scithese programs than it was for a British entific authorship is not mainly about resident of African descent, because of writing a paper, but rests mostly on a inequitable school resourcing in the U.K. researcher being able to provide authoRasekoala, a Nigerian chemical engineer, rization of their results, certifying that took inspiration from that realization to they are checked and valid, and being get involved in science communication, willing to stand up and take blame, if first in underserved schools near her there are any mistakes. Pennock argues U.K. university, and later across the Af- that artificial intelligence, at least at this rican continent. Rasekoala realized that point, is not a moral agent, and cannot another form of inequality was the lack authorize any results, which makes it of access to scientific research in Indig- an inequitable practice to try to assign enous African languages. This barrier AI coauthorship. also hindered the ability of science comAre there ways that equity influencmunicators to work directly with Afri- es your research decisions and practiccan communities to address the societal es? Join us on social media or write us challenges that face each specific com- a message through our website to tell munity. Rasekoala and her colleagues us about it. set up a science communications train—Fenella Saunders (@FenellaSaunders) 130

American Scientist, Volume 112

EDITORIAL Editor-in-Chief Fenella Saunders Managing Editor Stacey Lutkoski Consulting Editor Corey S. Powell Senior Features Editor Katie L. Burke Book Review Editor Jaime Herndon Contributing Editors Sandra J. Ackerman, Emily Buehler, Christa Evans, Jeremy Hawkins, Efraín E. RiveraSerrano, Flora Taylor, Sarah Webb Editorial Associate Mia Evans

ART Art Director Barbara J. Aulicino

DIGITAL Digital Managing Editor Nwabata Nnani

ADMINISTRATION EDITORIAL CORRESPONDENCE American Scientist P.O. Box 13975 Research Triangle Park, NC 27709 919-549-4691 • [email protected] CIRCULATION AND MARKETING NPS Media Group • Jamie Fallon, account director ADVERTISING SALES [email protected] • 800-243-6534 SUBSCRIPTION CUSTOMER SERVICE American Scientist P.O. Box 193 Congers, NY 10920 800-282-0444 • [email protected]

PUBLISHER SIGMA XI, THE SCIENTIFIC RESEARCH HONOR SOCIETY President Marija Strojnik Treasurer David Baker President-Elect Kathy Lu Immediate Past President Nicholas A. Peppas Executive Director & Publisher Jamie L. Vernon

EDITORIAL ADVISORY PANEL Richard Boudreault, University of Waterloo René Fuanta, East Stroudsburg University Simson Garfinkel, AI2050, Schmidt Futures Sonya T. Smith, Howard University Caroline VanSickle, Des Moines University American Scientist gratefully acknowledges support for engineering content through the Leroy Record Fund. Sigma Xi, The Scientific Research Honor Society is a society of scientists and engineers, founded in 1886 to recognize scientific achievement. A diverse organization of members and chapters, the Society fosters interaction among science, technology, and society; encourages appreciation and support of original work in science and technology; and promotes ethics and excellence in scientific and engineering research. Printed in the USA

Many Sides of Science To the Editors: It struck me that two adjacent articles in the March–April issue show a strong contrast in their approaches to doing science. Robert Pennock’s “The Call of Science” (Science and Engineering Values) highlights the essential role of evidence, while also mentioning the importance of honesty, objectivity, perseverance, and humility. Caryn Babaian, on the other hand, emphasizes the roles that visualization, imagination, and artistic creativity play in scientific discovery and understanding in her article, “Deconstructing DNA Beyond the Helix.” What a rich ferment of talents comes to the fore to produce this magnificent edifice we call science! May each of us bring our strengths and contribute our gifts to this process of generating knowledge and understanding. Spoudon xynones indeed! I did notice that Babaian indicated in her article that Rosalind Franklin’s crystallographic results were obtained using electrons, whereas I believe she meant to write x-rays, or perhaps photons. E. Michael Attas Pinawa, Manitoba, Canada

Dr. Babaian responds: The atoms of the DNA fiber contain electrons that diffract x-rays; the beam directed at them is described as either photons or x-rays. Sometimes people describe x-rays as a stream of electrons because x-rays are produced in a cathode-ray tube, but “photons” is used more frequently. An x-ray is a packet of electromagnetic energy (photon) that originates from an electron cloud of an atom. So most accurately, the image was ob-

tained using photons emitted from electron clouds.

Solar Images To the Editors: As I was paging through the March– April issue of American Scientist, I was astounded to see in Bhimsen Shivamoggi’s article “Gas Dynamics of Solar and Stellar Winds” an image of the star LL Ori colliding with gas to create a “bow shock” effect (above).

American Scientist (ISSN 0003-0996) is published bimonthly by Sigma Xi, The Scientific Research Honor Society, P.O. Box 13975, Research Triangle Park, NC 27709 (919-549-0097). Newsstand single copy $5.95. Back issues $7.95 per copy for 1st class mailing. U.S. subscriptions: one year print or digital $30, print and digital $36. Canadian subscriptions: one year print $38, digital $30; other foreign subscriptions: one year print $46, digital $30. Print institutional rate: $75; Canadian $83; other foreign $91. Digital site license $200, print and digital institutional rate $275. Copyright © 2024 by Sigma Xi, The Scientific Research Honor Society, Inc. All rights reserved. No part of this publication may be reproduced by any mechanical, photographic, or electronic process, nor may it be stored in a retrieval system, transmitted, or otherwise copied, except for onetime noncommercial, personal use, without written permission of the publisher. Periodicals postage paid at Durham, NC, and additional mailing offices. Postmaster: Send change of address form 3579 to American Scientist, P.O. Box 193, Congers, NY 10920. Canadian publications mail agreement no. 40040263.

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NASA and the Hubble Heritage Team (STScI/AURA); Acknowledgment: C. R. O’Dell (Vanderbilt University)

Letters

Online | @americanscientist.org

Baby Shark Sighting Misrepresented in Media Coverage

Carlos Guana

A photograph of a small great white shark made headlines, but for the wrong reasons. Marine conservation biologist David Shiffman explains the coolest aspect of the study, which most outlets missed. www.amsci.org/node/5202 Brooding over Bees

Imported honeybee queens face disadvantages in new environments. Studying what makes bees successful or not in new environments could become more important as climate shifts and bees move to new areas. www.amsci.org/node/5200 The Burgeoning Bluesky Science Community

Now that Twitter has declined, this recently opened social media platform could be the next home for online science communicators. www.amsci.org/node/5199 The Many Aspects of Bison Conservation

Roger L. Di Silvestro’s new book Return of the Bison: A Story of

As a young postdoc trying out the new camera on the Mayall 4-Meter Telescope at Kitt Peak National Observatory in Arizona, I tested some large-format interference filters on the Orion Nebula. A few days later, having copied the imagery and printed it on a large print, I noticed a faint curved structure around one of the minor stars in the nebula. Additionally, I could pick out several bubbles surrounding other stars. A few months later, I had begun a survey of the Milky Way searching for faint nebular structures. I noticed another partial shock associated with Zeta Ophiuchi, a single star located in the constellation of Ophiuchus. Several of us completed that survey that extends around the entire Milky Way in a 14-degree-wide band. A few years later, I had moved to Goddard Space Flight Center in Maryland where I met Sabatino Sofia, one 132

American Scientist, Volume 112

Survival, Restoration, and a Wilder World paints a hopeful picture. South Dakota State University bison biologist Jeff Martin questions whether that depiction is too good to be true. www.amsci.org/node/5190

Check out AmSci Blogs

The Seventh Claim

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The history of frequency hopping shows that scientific advances are rarely individual efforts. On our Long View blog, cosmologist Tony Rothman provides a follow-up to his article, “Random Paths to Frequency Hopping” (January– February 2019). www.amsci.org/node/5201

of the foremost astronomers on the structure of the Sun. In a conversation one day, I showed him several prints, which led to a the first observational paper on distorted interstellar bubbles. Later, we published a number of papers describing the effects of early star associates that create superbubbles. And after that, astronomers using the Hubble Space Telescope produced the image that you included in your article. Theodore R. Gull Emeritus Astronomer NASA Goddard Space Flight Center

Gibbs’s Legacy To the Editors: I read with great pleasure Lee S. Langston’s wonderful article on J. Willard Gibbs (“The American Inventor of Modern Thermodynamics,” Technologue, March–April 2024). I taught at Yale University for 14 years and heard

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many tales about Gibbs. In one story, Michael Faraday came to visit Yale. He was greeted at the train station by the governor of New Jersey, the president of Yale, and other dignitaries. He went down the line shaking hands, and when he came to the end he exclaimed, “Where is Gibbs?” Well, of course, no one in the line even knew who Gibbs was. Ted W. Reid Lubbock, TX

How to Write to American Scientist

Brief letters commenting on articles appearing in the magazine are welcomed. The editors reserve the right to edit submissions. Please include an email address if possible. Address: Letters to the Editors, P.O. Box 13975, Research Triangle Park, NC 27709 or [email protected].

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Spotlight | Nature-inspired robotics

Slithering Robots to the Rescue The biomechanics of nematode movement is informing new ways to design wormlike machines that can navigate difficult terrain.

Scientists have been trying to build snakelike, limbless robots for decades. These robots could come in handy in search-and-rescue situations, where they could navigate collapsed buildings to find and assist survivors. With slender, flexible bodies, limbless robots could readily move through confined and cluttered spaces such as debris fields that are inaccessible to or too dangerous for human rescuers, but where walking or wheeled robots tend to fail. However, even the most advanced limbless robots have not come close to moving with the agility and versatility in difficult terrain of worms and snakes. Even the tiny nematode worm Caenorhabditis elegans, which has a relatively simple nervous system, can navigate through difficult physical environments. As part of a team of engineers, roboticists, and physicists from the Georgia Institute of Technology led by Daniel I. Goldman and Lu Hang, we wanted to explore this discrepancy in performance. Most attempts to create wormlike robots have used a neuroscience approach in an attempt to recreate how animals sense and react to obstacles. Instead of looking to neuroscience for a solution, our team turned to biomechanics to build a robot model that drove its body using forces similar to how worms and snakes power their movement. Biomechanical Design Organisms have evolved intricate nervous systems that allow them to sense their physical surroundings, process that information, and execute precise body movements to navigate around obstacles. In robotics, engineers might design algorithms that behave like neural systems. The algorithms process 134

American Scientist, Volume 112

information from sensors on the robot’s body—a type of robotic nervous system—and use that information to decide how to move. These algorithms and systems are usually complex. Our team wanted to figure out a way to simplify these systems by highlighting mechanically controlled approaches to dealing with obstacles that don’t require sensors or computation. To do that, we turned to examples from biology.

For a robot to complete the same task, scientists can either design an algorithm that relies upon sensors, or they can carefully design a physical system that automatically reacts to obstacles. Animals don’t rely solely on their neurons (brain cells and peripheral nerves) to control movement. They also use the physical properties of their bodies—for example, the elasticity of their muscles—to help them react to their environment spontaneously, before their neurons even have a chance to respond. Whereas computational systems such as algorithms are governed by the laws of mathematics, mechanical

systems are governed by physics. For a robot to achieve the same task, either scientists can design an algorithm that relies upon sensors, or they can carefully design a physical system that automatically reacts to obstacles. For example, limbless robots and animals move through the world by bending sections of their bodies left and right, a type of movement called undulation. If they collide with an obstacle, they have to turn away and go around it by bending more to one side than the other. Scientists could build a robot that can handle obstacles by attaching sensors to its head or body. They could then design an algorithm that tells the robot to turn away or wind around an obstacle that it “sees” or when it “feels” a large enough force on its head or body. Alternatively, scientists could carefully select the robot’s materials and the arrangement and strength of its motors so that collisions would spontaneously produce a body shape that turns to avoid an obstacle without the use of sensors. This robot would have what scientists call mechanical intelligence. Legged and aerial robots often incorporate both strategies of robot development; however, less is known about the forces behind undulation, so most limbless robots have used the algorithmic approach. If researchers can understand the biomechanics of how undulating organisms’ bodies respond to contact with objects in their environment, they can design better robots that can deal with obstacles without relying solely on complex algorithms. Designing Mechanical Intelligence If you compare a diverse set of undulating organisms with the increasingly large zoo of robotic “snakes,” one difference between the robots and biological undulators stands out: Nearly all undulatory robots bend their bodies using a series of connected segments with motors at each joint. In contrast, all limbless organisms, from large snakes to microscopic nematodes, bend not from a single, rotational joint–motor system but instead through two bands of muscles on either side of the body. To an engineer, this design initially seems

cables

cuticle

servo motors passive joints

muscle

5 centimeters

nerve cord

time = 0

time = 3 seconds

time = 0

time = 40 seconds

200 micrometers

The microscopic nematode Caenorhabditis elegans provided inspiration for limbless robots that can navigate around obstacles. Nematodes activate bilateral muscle bands to undulate their bodies and propel forward (upper left). The authors and their colleagues designed a mechanically intelligent limbless robot (MILR) that mimics this action through a series of cables and pulleys that alternately tighten and relax (upper right). The nematode (lower left) and MILR (lower right) were each able to bend and move around obstacles using undulating locomotion.

counterintuitive. Why control something with two muscles or motors when one could do the job? To get to the bottom of this question, our team built a new robot called MILR, for Mechanically Intelligent Limbless Robot, inspired by the two bands of

Head-on collisions that would stop or jam a neuroscience-based robot instead naturally led to a redirection around the obstacle for the mechanically intelligent robot. muscle on snakes and worms. MILR has two independently controlled cables that pull each joint left and right, bilaterally. We found that this method allows the robot to spontaneously move around obstacles without having to sense its surroundings and actively www.americanscientist.org

change its body posture to comply with the environment. Rather than mimicking the detailed muscular anatomy of a particular organism, MILR applies forces to either side of its body by spooling and unspooling a cable. This system mirrors the muscle activation methods that snakes and nematodes use, in which the left and right sides take turns activating. The body turns by tightening the cables on one side while the cables on the other side relax and are pulled along passively. By changing the amount of slack in the cables, we can achieve varying degrees of body stiffness. When the robot collides with an obstacle, it selectively maintains its shape or bends under the force of the obstacle, depending on the cable tension, and whether the obstacle struck on the activated side. We found that if the robot was actively bending to one side and it experienced a force in the same direction, the body complied with the force and bent further. If, alternatively, the robot experienced a force that opposed the bend, it would remain rigid and push itself off the obstacle. Because of the pattern of the tension along the body, head-on collisions that would stop a simply controlled, serially connected robot instead naturally led to

10 centimeters

a redirection around the obstacle for the mechanically intelligent robot. MILR could push itself forward consistently. To investigate the benefits of mechanical intelligence, we built tiny obstacle courses and sent nematode worms through them to see how well they performed. We sent MILR through a similar course and compared the results. MILR moved through its course about as effectively as the real worms. When they collided with obstacles, we noticed that the worms and MILR responded with the same types of body movements. The principles of mechanical intelligence extend beyond the realm of nematodes. Future research could look at designing robots based on a host of other types of organisms for applications ranging from search and rescue to exploring other planets. —Tianyu Wang and Christopher Pierce Bibliography Hutson, M. 2017. Searching for survivors of the Mexico earthquake—with snake robots: “Slither-and-rescue” mission yields lessons for the next disaster. Science doi:10.1126 /science.aaq1195 Wang, T., et al. 2023. Mechanical intelligence simplifies control in terrestrial limbless locomotion. Science Robotics 8:eadi2243. Tianyu Wang is a PhD student in robotics at the Georgia Institute of Technology. Christopher Pierce is a postdoctoral scholar in physics at the Georgia Institute of Technology. This article is adapted from a version previously published on The Conversation (theconversation.com). Email for Wang: [email protected] 2024

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Courtesy of Tianyu Wang

100 micrometers

pulleys

Infographic | Peppermint Narwhal: Sea Turtle Files

SEA TURTLE & OCEAN HOLIDAYS JUNE JUNE 8 JUNE 915 JUNE 16

WORLD OCEAN MONTH WORLD OCEAN DAY SEA TURTLE WEEK WORLD SEA TURTLE DAY

GREEN (Chelonia mydas) ENDANGERED

soft-shelled flexible carapace (upper part of shell)

LEATHERBACK (Dermochelys coriacea) VULNERABLE

largest of the seven sea turtle species

front and rear flippers lack claws

5 distinct dorsal ridges

2 prefrontal scutes (external shell plate or skin scale)

1 claw on each front flipper

1 claw on each rear flipper

RANGE: Leatherback

2 postorbital (eye) scutes

interprefrontal scute

2 claws on each front flipper

only sea turtle that is predominantly herbivorous as an adult

RANGE: Green

LOGGERHEAD

5 pairs of lateral scutes

4 pairs of lateral scutes

2 prefrontal scutes 1 claw on each round and front flipper flat carapace

(Caretta caretta) VULNERABLE

4 pairs of lateral scutes

Margins folded and covered by waxy scutes

smallest geographic range of the seven sea turtle species

FLATBACK 1 claw on each rear flipper

2–3 claws on each rear flipper

(Natator depressus) DATA DEFICIENT

RANGE: Loggerhead

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American Scientist, Volume 112

RANGE: Flatback

© 2024 Peppermint Narwhal

largest of the hardshelled sea turtles

4 prefrontal scutes 2 claws on each hawklike front flipper beak

KEMP’S RIDLEY

0.612meters ft (0.61 (2 feet) m)

HAWKSBILL (Eretmochelys imbricata) CRITICALLY ENDANGERED

4 pairs of lateral scutes

only species with overlapping scutes

RANGE

OLIVE RIDLEY

0.61–0.76 2-2.5 ftmeters (0.61-0.76 (2–2.5 feet) m)

2 claws on each rear flipper

HAWKSBILL

primary threat: shell harvesting for use in making jewelry and decorative items

0.76–0.91 2.5-3 ftmeters (0.76-0.91 (2.5–3 feet) m)

RANGE: Hawksbill

4 prefrontal scutes 1–2 claws on each front flipper

FLATBACK

3-3.5 0.91–1.07 ft meters

(0.91-1.07 (3–3.5 m) feet)

OLIVE RIDLEY (Lepidochelys olivacea) VULNERABLE

6 or more pairs of lateral scutes

GREEN

0.91–1.52 3-5 ftmeters (0.91-1.52 (3–5 feet)m)

1–2 claws on each rear flipper

RANGE: Olive Ridley

most abundant sea turtle in the world: although numbers greatly reduced from historical estimates LOGGERHEAD

KEMP’S RIDLEY

HUMAN

0.91–2.80 3-9.2 ftmeters (0.91-2.80 (3–9.2 feet) m)

1.75 meters

(Lepidochelys kempii)

(5.75 feet)

CRITICALLY ENDANGERED

4 prefrontal scutes

smallest of the seven sea turtle species

1 claw on each front flipper

5 pairs of lateral scutes

LEATHERBACK

1.8–3.05 6-10 ftmeters (1.83-3.05 (6–10 feet)m)

1–2 claws on each rear flipper RANGE: Kemp’s Ridley

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SEA TURTLE SIZES 2024

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First Person | Elizabeth Rasekoala

Global Discourse on Science Communication

How did you begin your career, and how did that lead you to science communication?

Science communication has been a passion, something that I’ve done alongside my full-time career as a chemical engineer in industry. What I’ve been doing in science communication has been about giving back to and advancing the field. The spark came when I moved from my home country, Nigeria, to do postgraduate studies in chemical engineering in a UK university in the late 1980s. I didn’t know I was Black until I got there. We had postgraduate students from every part of the world. But none of the students of color were from the United Kingdom. And when you looked at the undergraduate level, there was not a single Black British student in the three-year undergraduate course. Not one. I was struck by this profound racial dichotomy, and I will always be grateful that I had a supervisor professor whom I was able to have very straightforward conversations with at this early stage. I remember asking him, “Prof, what the heck is going on here?” And he was absolutely candid. No defensiveness. He said, “We have a problem here in our British science education system. It is rank with hypocrisy. We go round the world telling everybody how fantastic our education system is. African students like you can come into this university, and yet Black children going through our education system in the UK will never be able 138

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to come here—not because they are academically unable, but because our education system disadvantages them in these subjects.” Just a 15-minute walk from that university was a huge conurbation of mainly Black British and African Caribbean peoples. And they might as well have been on another planet. That was the beginning, then, for me to pull together people in networks—hence, African Gong in later years. Once you had that realization, how did you start these networks?

My first network was the African Caribbean Network for Science and Technology in the United Kingdom. I brought together colleagues and peers to start engagement in inner city schools at primary and secondary levels. That was when we saw that science communication was a critical factor in terms of how young Black kids perceived science, themselves as scientists or not, and access and attainment issues. We put together an excellent writeup on this: “The Black Hole in Science Ranks,” which I was fortunate to present at the American Educational Research Association in 1998 in San Diego. That was an eye-opener for many colleagues. That took us from the school system into the science communication arena. How did African Gong begin?

In 2016, I gave a keynote speech at Ecsite [the European Network of Sci-

Courtesy of Amirali Momeni

Elizabeth Rasekoala is the president and a founding member of African Gong, a network of organizations from across Africa working to improve public understanding of and engagement with science and technology. In 2023, she edited and published the book Race and Sociocultural Inclusion in Science Communication (Bristol University Press). She also gave the keynote address at the Inclusive SciComm Symposium in October 2023. She has been working on science communication, meaning scientists communicating with the public about their work, since her early career as a chemical engineer. She spoke to senior features editor Katie L. Burke. This interview has been edited for length and clarity. ence Centres and Museums] in Graz, Austria. In the 1990s, I was the only Black person at Ecsite out of about 100 people. In 2016, I found myself delivering a keynote speech to an audience of just over 1,000 people. I could literally stand there and count the number of people of color present to be about 10. In other parts of the Global South, I have engaged with different science communication networks, such as RedPOP [Red de Popularización de la Ciencia y la Tecnología en América Latina y el Caribe (Latin American and Caribbean Network for the Popularization of Science and Technology)] in Latin America. I remember challenging the Brazilians: In a country of 200 million people—56 percent of whom identify as Afro-Brazilian—I have never seen an Afro-Brazilian in any science communication event in Brazil. This country has the largest number of people of African descent outside the African continent. I saw this racial dichotomy in Latin America, and I saw it in Asia. And I began to realize what a massive global problem this is. In 2014, we had a big science communication conference in Salvador, the most African part of Brazil. You walk on the road, and everybody looks like me. Then at this conference center, we found that the only people of color there were us—about 12 Africans, and not one single Afro-Brazilian. That was when we decided to come together to set up this network. We were the last regional science communication network to be formed. There

was Ecsite in Europe; RedPOP in Latin America and the Caribbean; ASPAC [Asia Pacific Network of Science and Technology Centres] in the AsiaPacific; and NAMES [North Africa and Middle East Science Centers Network] in North Africa and the Middle East. Your approach centering African languages in science communication is unique. How has your experience with various languages affected your perspective on science communication?

My mother is Benin and my father is Yoruba, so we spoke those two languages at home. But in Nigeria alone we have more than 200 languages and dialects. My mom speaks eight languages. When I was younger, I was speaking four, five, six—and that was all before English. Part of the legacy of the colonial experience is this entrenched dominance of European languages. We all learn science in school in European languages. The opportunities to develop science vocabulary in our local Indigenous African languages are very limited. With most other topics, we are able to speak without having this whole framing in a European language. But when it comes to science, we have no other option but to switch into English or French or Portuguese. If we restrict science communication on our continent to European languages, we are simply going to engage with a small urban elite. If you go to the rural areas where most of our people live, nobody speaks in English. A science communication exercise in English would totally lose everybody, even within the urban areas. If we want to break out of this elitist bubble, we have to use local African languages. In 2020 African Gong partnered with the African Institute for Mathematical Sciences to offer science communication workshops to their master’s students, located in several different African countries. These workshops were in English yet encouraged the participants to develop outreach about their research in their Indigenous African languages. How did this idea come about, and how did you implement it?

The challenge has been getting science communication firmly on the agenda in terms of policy—because if these things don’t get into the policy space, resources are never allocated. The policy space had been a struggle until www.americanscientist.org

2014, when the African Union Commission brought into place the Science, Technology, and Innovation Strategy for Africa. That was a real “wow” moment to have continental recognition for science communication. African scientists and researchers were being expected to communicate their research, but nobody was giving them the capacity in terms of skills, aptitude, motivation, or any kinds of tools to do the job. Then, we realized that in a sense it’s a good thing that there’s nothing on the ground, because we can avoid the baggage of Eurocentric hegemonic norms and create

Sociocultural inclusion must define excellence in science, rather than continuing to be an optional extra. a wholly Afrocentric science communication capacity-building program. What a wonderful opportunity. That was how we conceptualized the program called Africa Scientifique Leadership, Knowledge, and Skills for Science Communication. It was premised on principles of Afrocentricity— mainstreaming African culture and context, African languages, sociocultural inclusion, scientific culture, and innovation. We targeted this program at the young emerging career level because we wanted transformation and sustainability. When you have limited resources, you need to invest them where they have the most longterm sustainability. Another key aspect was to make sure that we had gender equity among the participants. And believe you me, in a field such as mathematical sciences where we started, it was a struggle. In 2020, 25 percent of the cohort were female participants. And we have worked since then to take that figure up to 50 percent, which we achieved in 2021, 2022, and 2023. We realized that the best way to sustain this program was to deliver it in partnership with African institutions, and the first institution that came on board was the African Institute for Mathematical Sciences (AIMS). And

they said, “We have realized that our master’s students have a real challenge communicating their research with the public. Let’s work together.” We had students from different parts of the continent, and that made for very interesting discussions and dynamics. There were students from African francophone countries, anglophone countries, West Africa, Southern Africa, and different regions. What are some examples of the students’ science communication projects?

One student, Thandiwe Dlamini, went back to Swaziland—now called Eswatini—to work on COVID-19 vaccine uptake. She wanted to enable her church community to deal with antivaccine sentiments. She came up with an activity using complex mathematical theory to engage her church members, adults, and youth. It was all done in her African language. She managed to get 60 percent of them to change their minds after her activity and agree that they would get vaccinated. It was amazing for her to get that success rate. Another student named Everlyn Chimoto went back to Kenya. She decided to engage with her peers and say, “Folks, we are all using technology, but not in our African languages.” And she started to create a sense of advocacy. She’s now working on this topic for her PhD, using mathematical theory to work on translation systems on the internet that use African languages. Everlyn was one of the winners of our female excellence awards. In the three-day intensive workshop, we provide two excellence awards for students. It’s a certificate, with a cash prize. That has been a big issue in science communication, in that it’s often done as service and volunteer work, but there are not always incentives to do it. Having an award is about practicing what we preach and realizing that one of the barriers is rewards and incentives. One of the core elements of Afrocentricity is that our science communication activities should enable us to work with African communities to address real societal challenges that our communities are dealing with. Students came up with proposals about using mathematical probability theory to deal with problem gambling, drunk driving, and optimizing taxi routes. Minibus taxis are critical to transportation in Black and African communities. These 2024

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My role model was my professor, all the way back in the late 1980s. This topic needs to be addressed with that same degree of candor and straightforwardness, without defensiveness—just tell it as it is. Did editing your recent book change your thinking in some way, or reveal something new to you?

AIMS House of Science

Everlyn Chimoto participated in African Gong’s Africa Scientifique Leadership, Knowledge, and Skills for Science Communication workshop in 2021. Her outreach project in her home country of Kenya led to her current PhD research on incorporating Indigenous African languages into online translation technologies. Her project won a female excellence award from the program.

are the kinds of science communication activities that you wouldn’t see in a European or U.S. context, but they speak so powerfully to African Indigeneity. Your recent book brings together scholarship and practice from a wide range of science communicators, and it is especially notable for including scholars in the Global South. What needs in the field were you aiming to address as you put together this book?

We were trying to address three things: The first need was to create a globally inclusive platform where these discourses, knowledge sharing, and paradigm-shifting ideas for transformative change on race and sociocultural inclusion in science communication can come together in a cohesive set of narratives and impactful frames, so that we break through the circular nature of these discourses and challenges. Second, there was a need to bring to the fore the voices and lived experiences of the many Black, Indigenous, and people of color who have been advocating for race and sociocultural inclusion in science communication across the various regions of the world—many unseen, unheard, and unknown—so that their diverse experiences can bring 140

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sharper insights into what transformation in diversity, equity, and inclusion should look like from their pivotal expert perspectives. The little bit that is out there on these issues—with no disrespect—tends to be very tokenistic and extractive, because it is coming from the Eurocentric perspectives of well-intentioned colleagues. They want things to change. They want improvement. But as we say in one of our African proverbs, “It is only the person who is wearing the shoe that can tell you exactly whether it is pinching at the toes or pinching at the heels.” Third, we wanted to bring to the fore innovative solutions and good practice exemplars that challenge the inertia in the science communication field with regard to sociocultural inclusion issues, so that we can advance the pace of change in contemporary developments in science communication. In short, we want to situate sociocultural inclusion at the core of what defines excellence in the field, rather than continuing to be an optional extra or a nice-to-have. Can we hold the field to account and say if it is not inclusive, it is rubbish? Can we move away from just numbers to look at qualitative assessments of what excellence means in science communication?

The research in many of the chapters uncovered the profoundly mindboggling fact that scientific knowledge cannot be inclusively communicated when it has not also been inclusively generated, researched, and advanced in the first place. A thread throughout the book explored the Global North–South divide, which prompted the question: How fairly are the fruits of scientific endeavors shared across the globe? Who benefits the most and the least? Again, you don’t think about these issues having an impact in terms of science communication. But they do. The legacies of these perceived inequalities impact trust in science. How does one sustain a culture of inclusion when institutions are so resistant to change?

We need to break this lack of connection between different regions. That is how you deal with the resistance to change in institutions. If you can’t even get people of color across the Global North and South synergized, having a real cohesive sense of their mutual challenges, then how do we support one another? After my keynote at the Inclusive SciComm Symposium, I was engaging with one of the African American ladies who was there, and she said, “I thought you had it made in Africa. I didn’t know you were dealing with these issues, too.” So for me, that was a real light bulb moment. It really speaks to the importance of having more of these dialogues. We need collective activism. And it needs to come from solidarity between practitioners in the Global North and South, across race, gender, and all the other paradigms. No one can do it alone. No one region of the world can do it alone. We need to bring that collective strength and understanding to effect change. Am

Sci

A companion podcast is available online at americanscientist.org.

Briefings

I

n this roundup, managing editor Stacey Lutkoski summarizes notable recent developments in scientific research, selected from reports compiled in the free electronic newsletter Sigma Xi SmartBrief: www.smartbrief.com/sigmaxi/

Invasive Insects Alter Lions’ Diet

Philipp Hoenle

A non-native species of ants has shown how one tiny, invasive species can have knock-on effects that alter an entire ecosystem, including the behaviors of the largest animals and predators. Across the savannas of East Africa, native acacia ants (several Crematogaster species) live in whistling-thorn trees (Vachellia drepanolobium), which provide them with shelter and nectar. The ants, in turn,

protect their homes by biting and stinging elephants that would attempt to eat or trample the trees. Lions also rely on the whistling-thorn trees as cover when hunting zebras. Invasive big-headed ants (Pheidole megacephala) have disrupted this ecosystem’s delicate mutualism. The foreign ants overwhelm the acacia ants, killing the adults and eating their eggs. Without the acacia ants’ protection, the whistling-thorn trees fall victim to elephant herds, which in turn reduces lions’ coverage when hunting. Zebra kills have dropped significantly in areas where big-headed ants are present, but the lion populations have not declined, probably because they switched to hunting African buffalo. The long-term effect of switching prey species is not yet known. The remarkable change one invasive insect can make on an ecosystem demonstrates the importance of fragile mutualisms in maintaining environmental health. Kamaru, D. N., et al. Disruption of an antplant mutualism shapes interactions between lions and their primary prey. Science 383:433–438 (January 25).

Martian Pull on Earth’s Oceans Gravitational forces from Mars may contribute to deep whirlpools that disrupt the seafloor on Earth. A team of geoscientists led by Adriana Dutkiewicz of the Uniwww.americanscientist.org

versity of Sydney in Australia found that periods of significant sediment disruption correspond with the 2.4-million-year cycle of Earth–Mars resonance—times when the planets’ gravities push and pull on each other. These astronomical grand cycles are difficult to detect, and there had been scant evidence of how interactions between planets affect the climate on such long timescales. The researchers applied spectral analysis to data collected from 293 deep-sea drill holes across all of Earth’s oceans. Underwater currents move sand and other materials along the ocean floor in fairly regular patterns, but striations in these samples indicate periods of greater disruption. Previous studies had looked at these seemingly anomalous striations over thousands of years and not found a pattern, but Dutkiewicz’s team widened their scope to millions of years and found that the ebb and flow of the currents correlate with astronomical grand cycles. Every 2.4 million years, Earth and Mars fall into a resonant pattern of motion; at those times, the enhanced effect of Mars’s gravity alters the shape of Earth’s orbit, bringing Earth slightly closer to the Sun and triggering a cascade of climate effects (unrelated to human-caused climate change). These small changes in the tiny pull of Mars boost ocean circulation on Earth, which in turn increases disruption of the ocean floor. (See “Operational Oceanography,” March–April 2022.) The study indicates that widening perspectives to astronomical scales may identify more ways that the Earth is part of a larger, interplanetary system. Dutkiewicz, A., S. Boulila, and R. D. Müller. Deep-sea hiatus record reveals orbital pacing by 2.4 Myr eccentricity grand cycles. Nature Communications 15:1998 (March 12).

Unfocused Foraging The seemingly modern problem of short attention spans may have had an evolutionary advantage in hunter-gatherer societies. Researchers have suspected that neurological differences such as attention deficit hyperactivity disorder (ADHD) might have helped nomadic groups that relied on exploration. To test this theory, a team of neuroscientists and psychologists led by David L. Barack of the University of Pennsylvania had 457 volunteer participants complete an online foraging task. The participants had 8 minutes to gather berries from virtual bushes. If they chose to stay at one bush, the number of berries available would deplete, but if they

moved to a new bush with more berries, they would lose time in traveling. After they completed the task, participants took a self-reported screening assessment for ADHD symptoms. The researchers found that those who crossed the ADHD threshold in the assessment scored higher in the berry-collection task than those who did not, and their patterns were similar to those calculated with optimal foraging theory. Participants with shorter attention spans moved between berry patches significantly sooner than those who did not meet the ADHD criteria, especially when the travel time between patches was short. The findings confirm that ADHD has advantages in some environments, including situations when exploration is favorable over exploitation. Barack, D. L., et al. Attention deficits linked with proclivity to explore while foraging. Proceedings of the Royal Society B 291:20222584 (February 21).

Smart Gloves Track Movement Researchers paired sensory yarns with machine-learning technologies to create gloves that can follow complex hand motions and gestures in an accurate and practical way. Hands are particularly difficult to track in real time because of the speed and variety of movements. Materials scientists at the University of British Columbia developed a material using helical sensor yarns, which consist of an elastic core wrapped in nanofibers and covered in a protective coating. Gloves made with this yarn are stretchy, flexible, and washable—properties that are necessary for the gloves to be practical for real-world use. The researchers used machine-learning to track the angles and movements of hand joints. They found that the gloves were more accurate and cost-effective than data collected from motion-capture cameras and did not have the problem of maintaining a clear field of view. The gloves have numerous potential applications, in such fields as human– computer interactions, gaming, robotics, and sign language communication. They also could be used in medical and rehabilitation settings, for such purposes as assessing and modifying exercises for people recovering from injuries or strokes. Tashakori, A., et al. Capturing complex hand movements and object interactions using machine learning–powered stretchable smart textile gloves. Nature Machine Intelligence 6:106–118 (January 12). 2024

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Perspective

The Racist Legacy of Urban Green Spaces City parks make people happier and healthier, a fact that fueled the movement to build them in the 1800s. But those benefits are not equitably distributed. Asia Murphy

T

he green space bordering the American River was the wildest place I knew as a kid. The park nearest my house in Sacramento, California, was all asphalt, mowed lawn, and damp wood chips. But in contrast, the unmarked place behind the state fair grounds, 20 minutes away by car, was truly untamed. As I walked up from the parking lot to the surrounding dirt road, the highest part of the greenway, I could see a swath of mist-veiled greenery sloping down into the river. I could breathe fresh air (and petrichor). Yellow-billed magpie calls cut through the quiet like two rasps rubbed together; black phoebe cheeps popped from dew-laden manzanita. Swallowtail caterpillar eggs to collect! Raptor cries to listen to! Horsehair worms to stare at in a mix of horror and disgust! Although he told it frequently, my dad loved to tell the anecdote of how he and the family pit bull had once come upon a puma in the area. It gave me the slight hope I might see one, too. It was only when I was older that I asked: Why was a roadside lot the only green space accessible to me? Why was there no formal way to experience large parks where pumas might be near my home streets? In 2021, Jesus Hernandez, through his business JCH Research, released a report called “Race and Place in Sacra-

mento.” The report detailed the historical development practices, tainted by segregation and discrimination, which led to the modern-day inequitable distribution of amenities and facilities in my home city. Areas filled with minorities and the poor, including my old haunts of south Sacramento, are more likely to have school closures and insufficient investment in public transportation infrastructure. These areas also have higher pollution burdens, including water and air contaminants, and are generally closer to facilities creating hazardous waste. No doubt related to the unhealthy environment, my old neighborhood also has above-average rates of asthma and cardiovascular disease. This information was a lot to take in, but I also wanted to know something that wasn’t included in Hernandez’s report: where parks and green spaces were and why. So, like the nerd I am, I ran a “quick” analysis using publicly available data. I gathered map data files on public parks and U.S. Census tracts, as well as tract-level Census data on race, ethnicity, and median income for 2020. I used Hernandez’s report to identify previously segregated tracts. For each Census tract, I estimated how much of it was covered by parks and green space, and, using structured equation modeling—an analysis considering relationships be-

tween the covariates in the model—I found something quite interesting. Park percentage in a Census tract significantly increased with the percentage of non-Hispanic white people living there. More white people equaled more park coverage. I soon learned that the pattern I saw was just one part of a much broader phenomenon. Across the United States, urban poor communities who are mainly Black and Latinx are faced with a green space shortage. Alessandro Rigolon and his colleagues at the University of Illinois have revealed that poorer American cities with higher percentages of Latinx and Black residents have smaller parks with less funding and fewer facilities and amenities. A study published last year by medical resident Issam Motairek and his colleagues in Cleveland, Ohio, investigated historical segregation’s influence on public health and the environment, looking at nearly 9,000 neighborhoods across the United States. They showed that neighborhoods that were historically white enclaves because of discriminatory practices are now “greener” than other neighborhoods. As an ecologist who has cameratrapped in Madagascar, and has friends and lab mates who work in the far-flung countries of Botswana, Kenya, and Nepal, I have long been in-

QUICK TAKE Public parks and vegetation are unequally distributed in U.S. cities, particularly those with a legacy of racist housing policies. Systemic biases were built into public landscapes.

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These legacies affect people’s health and well-being, as well as the health and diversity of the wildlife they might encounter around their neighborhoods.

Removing pernicious systemic inequities in access to public green spaces requires awareness first, and then community organizing around policies that have shown success.

proportion of non-Hispanic white people in the population (percent) 6–15 16–30 31–45

Courtesy of the author

46–60 61–78 public green spaces In Sacramento, California, the percentage of a U.S. Census tract area that is composed of public parks increases with the percentage of non-Hispanic white people living there. Racial inequities in access to green spaces are common in cities across the United States, especially in places where racist policies, such as redlining or forced displacement through eminent domain, were once common.

terested in the past and present injustices connected to protected areas and national parks. Yet this same injustice was present in my local city’s parks, and my field has done little about it. To true environmental injustice researchers, this unequal distribution of highquality greenways and parks in cities is old news. They call it nature inequity. And although nature inequity has its roots in the past, its influence continues to be felt today and will be felt in the future, unless we do something about it. The Rise of City Parks Although parks seem as natural to a neighborhood as a front lawn to a www.americanscientist.org

house, they were often specifically designed as havens for the upper classes who wanted to get away from urban filth (and the urban poor). Inequality was baked into their designs from the start, through policies that displaced the poor living on planned park grounds, excluded the “undesirable” from living in certain neighborhoods, or provided inadequate funding for green spaces in nonwhite communities. In the 1800s, with industrialization on the rise and cities becoming packed with people, the reputation of nature as wild and dangerous began to change. Maybe it was the stark contrast between grimy concrete jungles

and verdant meadows, streams, and crisp mountain peaks. For whatever reason, remaining natural environments weren’t to be destroyed. Instead, they were to be protected and helped, because they protected and helped us. Claude Monet gave all credit of his art’s “richness” to capital-N nature. Henry David Thoreau believed every town should have some park or green space, to be a “common possession for instruction and recreation.” Cities didn’t just want green space; they needed it. Parks were to be civilizing—in cities filled with immigrants seen as backwards, people of color deemed inferior, and the poor, who were stereotyped as immoral; parks were to be beautifying—in cities swamped with the refuse and offal and the noise of hundreds of thousands to million. And parks were to be healthful—in cities smothered by 2024

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Minnesota Historical Society

A real estate advertisement placed by Edmund G. Walton in the Minneapolis Morning Tribune on January 12, 1919, included a restriction banning Jewish tenants and tenants of color (highlighted text). Although the passage of the Fair Housing Act in 1968 banned this practice, areas in Minneapolis that had such race covenants still have more parks and green spaces to this day.

factory smoke and smog. Frederick Law Olmsted, one of the architects of the United States’ first landscaped urban park and one of its most popular urban parks today (Central Park in New York City) called parks the “lungs of [the] city.” Building Central Park displaced 1,600 people, including a thriving settlement of African American property owners, Seneca Village, living alongside many Irish and German immigrants. The middle and upper classes called for more parks in cities, and parks popped up across the country. In 1858, Central Park was opened to the public—the more undesirable of which were kept in check by police— to great fanfare. The Seneca Village inhabitants and landowners did not think this public space was an improvement on their destroyed homes. Because people design parks, decide where they should be located, determine what facilities and amenities they should have, maintain them, and upgrade them, parks are subject to our worst prejudices and biases. Many if not most parks were built on land forcibly taken from the impoverished and minorities. Once established, parks were segregated explicitly through law and implicitly through norms that established acceptable activities and behavior. One way of making sure one didn’t ruin one’s outside leisure 144

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by seeing too many Black or Jewish people at the neighborhood park was by making sure one’s neighbors weren’t Black or Jewish people. Race covenants inserted into property deeds prevented nonwhite people and other perceived undesirables from buying or living on certain land parcels. In Sacramento, the real estate board’s ethics code in 1924 stated, “A realtor should never be instrumental in introducing into a neighborhood .  .  . members of any race or nationality . . . whose presence will clearly be detrimental to property values in the neighborhood.” They assisted in this fight against “race mixing” by providing race covenant templates to realtors. During the Great Depression, the federal government created the Home Owners Loan Corporation (HOLC) to mitigate foreclosure rates by provid-

The presence of natural vegetation is correlated with higher birth weights, higher physical activity rates, lower mortality rates, and fewer depression symptoms. ing loans to homeowners. The HOLC became an important contributor to inequitable investment and development in cities across the United States. By creating “risk” maps based on a neighborhood’s racial or ethnic make-

up, they determined which neighborhoods were safe for home loans and further investment. Unsafe—read: majority-Black—neighborhoods were “redlined.” Even after the Great Depression, developers and investors continued using the HOLC risk maps. Whiter neighborhoods received disproportionate development and investment, which led to things like large, high-quality parks. Redlined neighborhoods were bypassed. Although this practice was banned in 1968 through the Fair Housing Act, the discriminatory practices were already entrenched. City development and investment to this day still often benefits neighborhoods that were historically—and largely remain— white enclaves. Proposed freeways and highways run right through impoverished and majority-minority neighborhoods; after all, they’re slums (due, of course, to the prejudiced lack of investment). Parks are destroyed or cut down in size. Christopher G. Boone of Arizona State University and his colleagues found in 2009 that white people had access to more park acreage within walking distance compared to Black people in Baltimore, and Dustin T. Duncan of the Harvard School of Public Health and his colleagues published a study in 2012 showing that predominantly Black census tracts had less park coverage in Boston. Both cities experienced redlining, and that racist legacy remains in the landscape. Green Spaces and Human Health Although they were steeped in Romanticism, Monet, Thoreau, and other famous white men of that time period who expounded on the benefits of nature were right. Dozens of studies now show that nature, whether gardens full of native plants, tree-lined streets, or large parks, is somehow connected with healthier, happier people. In 2018, Kelvin C. Fong and his colleagues at Harvard University reviewed 43 stud-

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2000 0.75 1500 gene diversity

effective population size

1000

0.50

500 0.25 0 majority nonwhite sites

majority white sites

majority nonwhite sites

Schmidt and Garroway, 2022

ies on health and the presence of natural vegetation, called greenness, finding that greenness is correlated with higher birth weights, higher physical activity rates, and lower mortality rates. Notably, an increase in greenness exposure is also connected to fewer depression symptoms. Another study led by Matthew H. E. M. Browning of the University of Illinois that investigated the link between green space and human health in 496 American cities discovered that greener cities had lower rates of obesity and poor mental health. Rachel Connolly of the University of California, Los Angeles, led a study that predicted that if Los Angeles increased tree canopy percentage in majority-Latinx and Black neighborhoods so that it was on par with the city at large, those residents would gain at least 57 millennia in life expectancy. In another study, Ming Kuo of the University of Illinois found that greenness was positively related to better academic performance at 318 Chicago public schools, even when controlling for socioeconomic status and race or ethnicity. Early positive experiences in nature often lead to continued interest in the environment later in life, as exemplified by yours truly. Of course, many of these studies are correlative, making the effect of green space (versus poverty, pollution, and other related factors) hard to determine. “Natural” experiments— in which residents experience an increase of green space without moving or experiencing a simultaneous improvement in their socioeconomic conditions—are difficult to find. Nadav L. Sprague of Columbia University and colleagues published a review in 2022 of the effects of green space on youth development; more than a third of studies had to be discarded because they didn’t have longitudinal data or an experimental study design. The remaining studies largely examined high-income, predominantly white populations in Europe (they did find positive associations between green space exposure and childhood mental health or well-being and behavioral outcomes). Samantha Gailey of Michigan State University published a study last year using a longitudinal dataset following California moms who didn’t move but who still experienced changes in residential green space (for example, the creation or destruction of a park) between the birth of two chil-

majority white sites

class amphibian

bird

mammal

reptile

Wildlife is more genetically diverse across several metrics (two shown here) in sites with more than 50 percent white residents, compared with sites with majority nonwhite residents. Thus, inequities in green space also affect residents’ access to diverse and healthy populations of wildlife.

dren. What Gailey found was that the second child born to a Black mom in areas with an increase in green space had a higher birth weight—associated with positive health outcomes—than the first. However, a higher percentage of the moms who stayed, particularly those who were Black, had some college education and private health insurance compared with moms who moved, which could be some of the reason for the beneficial outcome. People aren’t the only ones who benefit from—or are negatively affected

Building the Atlanta Public Safety Training Center would exacerbate nature inequity in one of the few places where nature equity has been present. by—the inequitable distribution of green space in cities. The luxury effect is a positive relationship between human wealth and wildlife presence or number of species seen across many cities. Larger green spaces are more likely

to be in a city’s richer areas, providing more resources for wildlife. Seth Magle of the Urban Wildlife Institute at Lincoln Park Zoo in Chicago and his colleagues found that mammal species richness increased with median income in nine North American cities. The legacy effect is another widespread pattern connecting a city’s historical development and urban nature: Longerestablished residential streets with larger, older heritage trees provide food and habitat for birds and other species. A study currently under peer review led by Cesar Estien of the University of California, Berkeley (UC Berkeley), discovered that non-redlined California neighborhoods had higher biodiversity rates, even when controlling for each neighborhood’s size. Although we’ve long known of the luxury and legacy effects, urban ecologists are beginning to investigate how other human-caused phenomena connected to nature inequity and environmental injustice affect urban ecosystems. Take pollution, for example. Countrywide analyses led by researchers from the Harrington Heart and Vascular Institute, Colorado State University, and the University of Texas have shown that people in historically redlined neighborhoods have less green space and are consistently exposed to higher rates of unhealthy air, noise, and light pollution. Noise and light pollution can reduce growth, increase stress levels, and decrease re2024

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ecological & evolutionary patterns & processes landscape heterogeneity disease dynamics resource distribution environmental pollutants

Schell et al., 2020/Reprinted with permission from AAAS

green space & tree cover urban heat islands impervious surface cover

structural racism & classism

residental gentrification law segregation resource employment enforcement political allocation rights immigration representation policy

systemic biases Structural racism and classism underpin landscape heterogeneity in cities, types of land surface cover, city temperatures, the presence of vegetation, environmental pollutants, resource distribution, and wildlife disease dynamics. In turn, these patterns of structural biases in the landscape affect ecological and evolutionary processes of organisms living in cities.

productive success in wildlife. Animals living in or near these historically redlined neighborhoods where pollution rates are higher experience more negative effects than those living in non-redlined neighborhoods. Smaller, fragmented habitat patches— present in higher rates in areas with poorer, nonwhite residents—can lead to absent or intensified interactions between species. Sicker, smaller, more stressed animals, changes in habitat use and activity patterns, higher pollution rates, habitat loss, fragmentation: All these stressors can, when constant and long-standing enough, influence evolution— or so posits a 2020 review in Science led by UC Berkeley’s Christopher Schell. Indeed, according to Chloé Schmidt and Colin Garroway of the University of Manitoba, genetic diversity—the very thing driving evolution—is reduced in wildlife living in or near neighborhoods 146

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with more nonwhite residents. Using nearly 8,000 publicly available genetic samples from 39 species, they showed that “neighborhoods that are largely non-White support smaller, more fragmented, less genetically diverse wildlife populations,” making these populations more vulnerable to local extinction. Equitable Green Spaces Climate change will make urban conditions more extreme—which will increase the importance of green space and increase the consequences of inequalities in access. However, our urban ecosystems might be able to help us. Trees provide shade, which can cool off people during heat waves and keep the air cleaner when smoke from nearby wildfires blows in. Green space lessens the risk of flash floods, because the unpaved ground is more pervious to rain than asphalt and con-

crete. These ecosystem services can benefit us—if they are present near our homes. We know that climate change will exacerbate the problems associated with unequal green space access. Unfortunately, the New School’s Pablo Herreros-Cantis and Timon McPhearson discovered that green space in New York City was severely lacking in lower-income areas with higher proportions of people of color, burdening them with unhealthy air pollution, higher temperatures during heat waves, and flash-flooding risk. Weiqi Zhou of the Chinese Academy of Sciences led a study showing that poorer, nonwhite people in 38 cities in the United States lived in neighborhoods with less tree canopy cover, leading to higher local temperatures, which could be fatal as the Earth gets warmer. We must increase green space in cities along equitable lines if we are to help our urban ecosystems help us. (See “Unequal Burden of Urban Heat,” March–April 2021.) What to do, then? How do we increase green space in our cities in an equitable fashion so residents (both human and wild) can be healthier, happier, and safer from climate change’s effects? First, we must acknowledge that the inequity exists. According to a 2023 study by Zbigniew J. Grabowski of the New School and his colleagues, less than 10 percent of official green infrastructure plans even mention nature inequity or related topics. This must change. Cities should examine their own local patterns of green space distribution with race and income to determine if inequity exists and, if so, its magnitude. Such analyses can be done quite easily; my analysis of Sacramento took me less than 4 hours. Only by acknowledging there is a problem will we fix it. Next, we must protect what green spaces residents in majority-minority areas already have. To do so, communities must organize and individuals must get involved in local politics. Go to your city council; get on speaking terms with your mayor. And when necessary, get in the streets and make a loud fuss. If you can’t get outside, donate to bail funds for those who do, and fight against the laws that designate community-organized protesting as “domestic terrorism” and make it harder for people to be bailed out using community-raised funds.

For example, the Atlanta Public Safety Training Center (also called Cop City) is slated to be built on a green space surrounded by neighborhoods with a statistically greater percentage of Black residents than other neighborhoods of Clayton, Dekalb, and Fulton Counties. This project has received intense backlash, not only because of what it means for criminal justice in Georgia, but also because of what residents would lose. This area is unique in that these nearby, predominantly Black neighborhoods of Atlanta have a statistically similar amount of green space compared with other, whiter areas in the three counties. Building this training center would exacerbate nature inequity in one of the few areas where nature equity has been present. Those in power ignored (and continue to ignore) the residents’ wishes, leading to sustained direct action and mutual aid, which is still happening today, despite domestic terrorism charges and Georgia’s SB63 bill outlawing nonincorporated bail fundraising. Finally, we must fight against the scourge of green gentrification. Rigolon and his coauthor, Jeremy Németh of the University of Colorado, found in 2020 that new parks developed be-

tween 2008 and 2015 in 10 U.S. cities, particularly ones with greenway-like functions, seemed to trigger gentrification of the surrounding areas. Eunah Jung of Cornell University described six neighborhood typologies in New York City, connecting green space to the socioeconomic conditions of the residents. One of the types, which described 16 percent of the neighborhoods, experienced sizeable decreases in Black and Latinx populations by the end of the study period in 2019. This type also experienced a 7 percent increase in park acreage and an 8 percent decrease in how far a park was from a neighborhood’s geographic center. Green space development should be widespread and equitably distributed to mitigate this phenomenon. Housing assistance should be easier to obtain. Policies such as New York City’s free representation in housing court for lowincome tenants facing eviction would make it harder for landlords to evict residents in revitalized neighborhoods. In addition, tenants should unionize so they can fight the unaffordable rent hikes that usually follow gentrification by collectively not paying rent. Parks and green spaces, despite their racist legacy, are one of the few

institutions left in the United States for communities. Only through community will we be able to make greener, more equitable cities for everyone. Bibliography Kephart, L. 2022. How racial residential segregation structures access and exposure to greenness and green space: A review. Environmental Justice 15:10.1089/env.2021.0039. Langhans, K. E., et al. 2023. Centring justice in conceptualizing and improving access to urban nature. People and Nature 5:897–910. Nesbitt, L., M. J. Meitner, C. Girling, S. R. J. Sheppard, and Y. Lu. 2019. Who has access to urban vegetation? A spatial analysis of distributional green equity in 10 U.S. cities. Landscape and Urban Planning 181:51–79. Schell, C. J., et al. 2020. The ecological and evolutionary consequences of systemic racism in urban environments. Science 369:eaay4497. Schmidt, C., and C. J. Garroway. 2022. Systemic racism alters wildlife genetic diversity. PNAS 119:e2102860119. Taylor, D. E. 1999. Central Park as a model for social control: Urban parks, social class and leisure behavior in nineteenth-century America. Journal of Leisure Research 31:420–477.

Asia Murphy is a postdoctoral researcher at the University of Arizona, studying how humans and urbanization influence species interactions, with a focus on carnivores. Twitter (X): @am_anatiala

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Science and Engineering Values

AI and Responsible Authorship Why my chatbot is not (yet) a coauthor. Robert T. Pennock

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uppose I do the experiments but use an artificial intelligence chatbot to write the report; should I list it as an author? If I only use the chatbot to flag typos or suggest fixes for grammatical errors, that question would never arise. But what if, to save time, I have the AI write the literature review section summarizing a set of articles I gave it? Now the words on the page are not my own. More significantly, what if I give it my experimental data to analyze and write up? As AI increases in power and capabilities, does it deserve credit as a coauthor? From Lovelace to LLMs In 1843, Ada Lovelace published what was arguably the first computer program, showing how an analytical engine—as mathematician Charles Babbage called his yet-unbuilt digital mechanism—could calculate a common sequence of rational numbers called Bernoulli numbers. A computer program is just a step-by-step procedure, but Lovelace’s algorithm could do something that at the time only a person could. An algorithm may run on a mechanical device with gears, on an electrical device with circuits, or on an abstract writing instrument and roll of paper that moves based on symbols written on it—a Turing machine, named after computer pioneer Alan Turing. The idea of artificial intelligence is that such artifacts can in principle be able to exhibit recognizable, if perhaps not exactly human, intelligent activity.

As a PhD student in the late 1980s, I worked with Herbert Simon, the Nobel Prize–winning polymath known as the father of AI for his pioneering theoretical and empirical work that founded the field. Simon argued that AI should be analyzed in terms of symbolic reasoning. I also heard computer scientist and cognitive psychologist Geoffrey Hinton, now called the godfather of AI, argue for and demonstrate early results of an alternative “connectionist” approach that focused instead on statistical associations in artificial neural networks

The write-up serves a vital function because it reports the evidence, but authoring is not the core part of research. (ANNs). ANNs were modeled on brain structures, with varying weights of connections between nodes governing the processing from input to output. The relative merits of these approaches made for vibrant debate and drove interesting research. For example, symbolic AI researchers analyzed the rules of expert reasoning and devised programs to simulate them. Hinton, who later received the A. M. Turing Award, and other connectionists devised better ways to train ANNs. For years, practical applications in both symbolic and con-

nectionist AI always seemed beyond the horizon, but the early 2020s saw rapid advances in their capabilities. By training an attention-based transformer model on massive amounts of text gathered from the internet, the weights of an ANN can be adjusted so that it becomes an adroit text manipulator. Such large language models (LLMs) take a text prompt as an input and then generate a string of output text based on predictions of what words should follow what came before. LLMs generally lack symbolic structure and are not yet very good at math, but various hybrid systems attempt to combine the strengths of both symbolic and connectionist models. Today LLMs can generate a convincing essay about Bernoulli’s mathematical discovery. Lovelace would be impressed. The term computer originally referred to a person who performed mathematical calculations—computations. When computing machines took over these clerical tasks, they also took over the term. Is AI poised to similarly replace authors? In particular, has AI come far enough to be responsibly included as an author of a scientific paper? Authorship Problematized To analyze the ethics of responsible scientific authorship, one must first consider the notion of authorship itself. On first pass, authorship seems problematic if only because the word is linked etymologically to the idea of authority and thereby to an unscientific, legislative notion of justification.

QUICK TAKE The use of artificial intelligence in the development of research papers raises the ethical question of whether AI tools should receive coauthor credit.

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Responsible scientific authorship is less about authoring the text of a research paper than it is authorizing the paper as a fair representation of the evidence supporting its findings.

AI agents might be able to dig up unknown references or even analyze original data, but they are not yet able to take responsibility for the research in an ethical sense.

Magic Studio

AI productions may or may not reflect reality, so users must be wary and check outputs themselves. An AI image generator was given the prompt “Ada Lovelace coding at a desktop computer” and created this fanciful illustration of that historical figure, who was involved in early computer algorithms. AI tools still don’t get basic things quite right, such as Lovelace here writing with a quill instead of using the keyboard. AI tools are powerful, but it is only moral agents who can bear responsibility for the use of what they generate.

On the legislative model, the say-so of the proper authority creates and justifies a law because a recognized authority is its author. But science brooks no such justification; a scientific conclusion is justified not by authority, but by observational evidence. Philosopher Blaise Pascal, writing in the 17th century during the scientific revolution, put the point bluntly: “On subjects in [the physical domain] we do not in the least rely on authorities—when we cite authors, we cite their demonstrations, not their names.” Indeed, presentations at the Royal Society from the early days of the scientific revolution commonly included a physiwww.americanscientist.org

cal demonstration of instruments, materials, and procedures. As far as possible, researchers exhibited phenomena, rather than just penning descriptions thereof. The write-up serves a vital function because it reports the evidence, but authoring it is not the core part of research. I’m a Scientist, Jim, Not a Novelist In 1983, the first version of Microsoft Word came out. I taught students how to use this new word processing tool, telling them it was their future. My mother had earned money in college typing classmates’ papers on her Smith Corona typewriter; today, kids

use Word in elementary school. LLM chatbots are the next big step in word processing but threaten a more uncertain future. Generative AI makes it easy to produce a research paper with little more than a clever prompt. The result may not be plagiarism in the usual sense of the word, but it isn’t original work either. I’m always dismayed when a student refers to a nonfiction science book we are reading as a novel. There is a stark difference between science and science fiction. This division ought to be obvious, but some postmodernist critics of science muddied the distinction, arguing that scientific practice may be described simply as the manipulation of texts. They portrayed science as a subset of literary activity— scientists “construct” the world (rather than discover it) by “writing” a “narrative.” Such “stories” may be accepted 2024

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Alan Turing (top left), Herbert Simon (top right), and Geoffrey Hinton (bottom) are pioneering figures in the development of artificial intelligence. One of Turing’s conceptual advances was the idea of using an imitation game—determining how well a person could spot a machine impersonating a human—as a test of computer intelligence. Simon argued that AIs should be evaluated in terms of symbolic reasoning. Hinton took an alternative approach that considered statistical connections in artificial neural networks, modeled on brain structures, with varying weights of connections between nodes governing the processing from input to output. Large language models are an application of this idea.

as true, but only because society has granted scientists, perhaps unwisely, this creative privilege. This view was seriously mistaken. Despite some interesting areas of overlap, the norms that govern production of reports of scientific discovery are crucially different from those that govern construction of works of creative fiction. The essential core of scientists’ work involves applying the scientific method of inquiry to an empirical research problem. Scientists must formulate a 150

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reasonable model that might explain a phenomenon of interest, design a justified experimental protocol to test it, carefully execute the procedure, gather data, and then analyze the results. When researchers follow the norms of the scientific method, they are not primarily authors or creators, but rather reporters and discoverers. Glorified Autocomplete? One might think that it is enough to disqualify AI from being an author of

a scientific paper by arguing that it is a fancy word processor that discovers nothing new. The text prediction facility of LLMs, impressive as it is, has been criticized as no more than a glorified autocomplete system. But this judgement may be too quick. Hinton says that he already detects an emergent intelligence capable of real reasoning and understanding. Lovelace’s program dealt with math, but she presciently speculated that the analytical engine might also be able to operate on other things, such as musical notes. Today, AIs can generate listenable music from user text prompts. Creativity is different from discovery, as we noted, so LLMs can’t just create an empirical finding. But if we connect one to sensors, couldn’t it analyze the data and possibly make a new discovery about the world? Simon thought that AI would be able to do just that. He and his colleagues investigated this possibility using a program they built called BACON, with heuristics thought to facilitate scientific discovery. They tested it on known cases with some remarkable early success, for instance, giving it planetary motion data and observing it rediscover Kepler’s third law. Today, LLMs are being trained on protein amino acid sequence data to generate candidate sequences to help discover useful novel enzymes. Of course, this technical ability is not enough to make AI a full-fledged discovery machine. One must be able to display the evidential relationships that connect such a machine’s outputs to existing scientific knowledge and recognize their import in extending that knowledge. A computer might record and process data from a radio telescope, but for the time being we still need a Jocelyn Bell, who discovered the first pulsar from such radio signals, to distinguish a meaningful signal from a glitch. These issues relate to several ethical principles that are important for understanding responsible authorship attribution in science. Truth and Tools The first ethical principle of science involves truth. The goal of science is to discover empirical truths about the natural world, which is why honesty is a core virtue in science. It doesn’t even make sense to seek a discovery without it. AI chatbots currently are not good at distinguishing truth from falsity.

They are often trained on indiscriminate internet texts, which provides rich diversity but questionable accuracy. Just as biased internet data can cause AI bots to exhibit racial biases, they can also lead to skewed reporting about factual matters. Falsities can also be generated because of the nature of the systems; LLMs don’t produce outputs by direct comparison with reality, but rather based on probabilistic patterns of texts. Thus, LLMs can produce what are referred to as hallucinations or confabulations, glitches where the bots output what their models predict to follow what came before, but which are not true. They put forward concocted statements with apparent confidence. LLMs may even support these false statements with references that they also made up. Unwary, trusting users are easily burned. All instruments must be calibrated, and AI is no different from other technical tools. Even mature software may have bugs. My research team recently encountered an obscure incompatibility between Mac and PC versions of Microsoft Excel that caused some cell data not to show up in searches, corrupting results until we figured out the cause. A new technology such as AI chatbots will have many more unexpected flaws. Tools are not always reliable, so it is incumbent upon users to perform the requisite checks. Bearing Responsibility Of course, humans can be unreliable and make mistakes as well. The difference is that although a malfunctioning tool can be the cause of mistakes, humans bear responsibility for them. This ethical concept is central in the original question about responsible authorship—what it means to be responsible. Colloquially, we often conflate the two different notions. For example, when investigating a traffic accident, we may ask what was responsible for the crash and conclude that it was brake failure. That is, we are asking for the cause. For a failed experiment, we may similarly identify a cause, such as a bug in a computer program. It is a different question to ask who was responsible for a failure—the mechanic, say, or the developer. This notion involves blame, which is an evaluative concept. In cases of success, responsibility brings credit. Either way, this second notion of responsibility takes www.americanscientist.org

us beyond the realm of mere causation and into the realm of ethics. One key aspect of ethical responsibility is contained in the term itself— responsibility involves being ready and able to respond. Responsible conduct of research implies a duty to ensure that things are done properly and to stand up to answer a call to accountability if something goes wrong. Scientific reasoning involves identifying the causal relationships that are evidentially relevant in the test of a model. It requires objectively assessing the data and skeptically watching out for possible biases, including one’s own. It requires humbly submitting to what that evidence shows, even if the results go against one’s favored model. And so on. For a scientific paper, responsibility implies a duty to honestly exhibit such evidence. To de-

Large language models can produce what are referred to as hallucinations or confabulations, glitches where the bots output what their models predict to follow what came before, but which are not true. serve credit as an author, one must be in alignment with and be able to take responsibility for such values. The Credits Historically, it was important to have a written statement of research not only to disseminate information, but also to establish priority. Scientists received, and for the most part continue to receive, relatively little financial remuneration for their labors. Their primary reward was the joy of discovery itself and the peer recognition that their work earned them. One of the roles of the Royal Society was to oversee deposits of sealed reports of discoveries, so that scientists could continue experiments to fully establish a result and pursue its elaboration without fear that other re-

searchers might scoop them before they were ready to make their work public. This issue brings up a third ethical principle for responsible authorship: justice. It is not equitable to give credit that is not earned. The issue of equity arises when authorship assignment is too coarse-grained. Such inequities can be avoided by moving to an attribution model that explicitly lists the specific responsibilities of the researchers. Instead of calling all participants “authors,” papers should list their roles and contributions. Depending on the type of research, these roles may range from general ones such as “Principal Investigator” to specific ones such as “Statistician” or “Virus samples contributed by . . .” Such a model of attribution—what I call “the credits” by analogy with film credits— better follows ethical principles of justice by recognizing and equitably distinguishing actual research roles. It supports responsibility by allowing one to receive just recognition in accordance with one’s true contributions. This model also helps in assignment of blame. Contributors are not equally at fault in cases of misconduct; explicit attribution identifies the parts of the research for which they actually bear responsibility. I proposed this credit attribution model in 1996, and various journals have since adopted some form of it, such as the Contributor Roles Taxonomy (CRediT), which classifies some common research roles. AI bots are not contributors, but just as film credits may list the use of Panavision equipment, researchers can cite AI agents in the same way that they would a specialized instrument. If AI bots are used substantively in the research or report, this use is evidentially relevant, and responsible authors should list them as tools. Ghostwriter in the Machine Computer programs have come a long way since Lovelace’s first algorithm. Today’s text generators may help or harm writing, but they are not authors in the moral sense. Whether they could ever become responsible sentient agents is not just a scientific and engineering question, but a philosophical one. Both Plato and Aristotle considered the implications of automata— machines capable of autonomous behavior. The 18th-century Swiss 2024

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Pierre Jaquet-Droz’s functional automaton, “The Writer,” could inscribe lines of text on note cards by means of a complex clockwork mechanism. Large language model AI chatbots produce text using pretrained neural networks instead of arranged physical gears and cams, but the process is no less mechanical.

watchmaker Pierre Jaquet-Droz built several clockwork automata to implement this idea. The most sophisticated was “The Writer,” a mechanical boy

What authorship means in the scientific context is not about authoring the text so much as authorizing the report as a fair representation of the evidence. he programmed to produce lines of text on note cards. Generative AI today can do far more, but it is still essentially “mechanical.” Could a mere mechanism ever be truly human or, as in the Japanese manga and anime movie Ghost in the Shell, is a human 152

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consciousness required? That title references the phrase “ghost in the machine,” which comes from British philosopher Gilbert Ryle’s critique of the idea of metaphysical separation of mind and body. Ryle argued that humans are also “just” mechanisms, but that state doesn’t prevent our being intelligent moral agents. AI bots can now pass Turing’s imitation game—in which an AI can fool a person into believing that it is a human—in some circumstances. One programmer recently trained a LLM to automatically converse with online potential dating partners, to filter down to compatible individuals before communicating personally. We have not yet achieved an AI Cyrano de Bergerac, but still. It takes more than simple intelligence to have a moral sense and bear responsibility, but we can’t rule out the possibility of a future AI ghostwriter. Endorsing the Check Science is an evidence-based discipline and eschews appeals to authority. A

scientific paper is not an act of creation but a report of evidence for a discovery. By putting one’s name on that report, a scientist is taking responsibility for its contents. What authorship means in the scientific context is not about authoring the text so much as authorizing the report as a fair representation of the evidence: I authorize it in the sense that I endorse it. Think of this act as the scientific version of endorsing a check. Signing off on a report indicates that I have performed the requisite tests—checked and double-checked the protocols, data, calculations, and results—and will stand by them. I put my name to it to affirm that I take responsibility for the experiments and analysis reported therein. If the evidence I report for the discovery is good, you can take it to the bank. Researchers who have been caught fabricating data, on the other hand, are like forgers whose checks have bounced. Having violated essential scientific values, they are no longer trustworthy. Their endorsement is worthless. AI is still just a tool. If it fails, we wouldn’t blame it morally but causally, and we would take steps to fix it. Like other powerful tools, AI is useful but can be dangerous. It must be used responsibly. It cannot, at least not yet, be itself responsible. Perhaps the future will bring an AI that can, and thereby will deserve credit as a coauthor. But for now, the responsibility lies entirely with me. Bibliography Hollings, C., U. Martin, and A. Rice. 2018. Ada Lovelace: The Making of a Computer Scientist. Oxford, UK: Bodleian Library Publishing. Langley, P., H. A. Simon, and G. L. Bradshaw. 1987. Heuristics for empirical discovery. In Computational Models of Learning, ed. L. Bolc, pp 21–54. Berlin: Springer-Verlag. Pennock, R. T. 1996. Inappropriate authorship in collaborative scientific research. Public Affairs Quarterly 10:379–393. Rothman, J. 2023. Why the godfather of AI fears what he’s built. New Yorker (November 13).

Robert T. Pennock is Sigma Xi Senior Fellow for Science and Engineering Values. He is a University Distinguished Professor at Michigan State University, where he is on the faculty of Lyman Briggs College, the departments of philosophy and computer science and engineering, and the ecology, evolution, and behavior program. His research involves both empirical and philosophical questions that relate to evolutionary biology, cognitive science, and the scientific character virtues. Email: [email protected]

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Ethics

The Rights of the Dead Human remains can hold great scientific value, but studying and displaying specimens without the subject’s consent is ethically dubious. Anita Guerrini

I

n 1786, Joshua Reynolds painted a portrait of the surgeon and anatomist John Hunter. Reynolds depicted Hunter gazing into the distance, caught in mid-thought, quill in hand. On the table in front of him, apart from inkwell and paper, are some books, one propped open to a page comparing the skulls and arm bones of humans and apes. Next to the books is an anatomical specimen under a glass dome. In the upper right-hand corner is a mantel holding another anatomical specimen in a glass jar. A pair of large skeletal feet suspended in the air next to the jar hint at the large skeleton attached to them and hanging from the ceiling. The painting was well-known, particularly after an engraving of it was made in 1788, and the dangling feet were also famous. Their inclusion in the portrait indicated that Hunter owned them and the skeleton to which he had reattached them. However, in life, they had belonged to the “Irish Giant” Charles Byrne. I first saw Byrne’s skeleton decades ago in the Hunterian Museum of the Royal College of Surgeons in London, among jars of preserved anatomical specimens that included an 18thcentury bishop’s cancerous rectum. The last time I saw the skeleton, in 2016, I was not allowed to photograph it. The following year, the outcome of the case of an ancient skeleton in the United States brought to a head longsimmering issues surrounding the

rights of the dead against the rights of museums to display their remains and of scientists to learn from them. The contrasts are many between Byrne and the man at the center of a court case, who died 8,500 years ago and was buried along what is now known as the Columbia River near Kennewick in Washington state. Nonetheless, there are similarities between them. They share stories of identity and ownership in the aftermath of colonialism. More broadly, both men seem to epitomize science’s appropriation of individual identities in the service of a larger impersonal goal of knowledge that presumably will benefit humankind. By this argument, a dead body has no value other than as a source of information. Yet the stories of these two men, vastly separated in place and time, are not merely stories of a cold and rapacious science, but of the intertwined desires and beliefs that the living project onto the dead, both in the 18th century and today, among scientists and among others who lay claim to the bodies of the dead. The dead themselves know nothing about it. Display without Consent For several years, Charles Byrne, born in 1761 in County Derry, exhibited himself for a fee to the public at fairs, in taverns and coffeehouses, and at private homes across Ireland and Britain. Newspaper advertisements and broadsides breathlessly proclaimed him to be the tallest man in the world, at a height

of 2.5 meters (8 feet 2 inches). We know little about him apart from his height, which was actually about 2.31 meters (7 feet 7 inches). His parents were of normal size, but, since he hired himself out for money while still in his teens, they were most likely poor. His handlers dressed him in the height of 1780s fashion, with silk stockings and lace cuffs, and broadsides posted on walls across London announced his arrival in April 1782. One broadside described “The Modern Living Colossus, Or, Wonderful IRISH-GIANT,” noting his “admirable Symetry [sic] and Proportion” and his “Vivacity and Spirit.” Byrne’s Irishness was part of his appeal. He was sometimes referred to, or referred to himself, as O’Brien, invoking an ancestry going back to the semimythical 11th-century Irish king Brian Boru, who in some tales was a giant. In Hilary Mantel’s 1998 novel The Giant, O’Brien, Byrne is a storyteller and myth-spinner, in contrast to Hunter’s cold rationality. Byrne was not the first Irish giant to display himself, and he would not be the last. Patrick Cotter, who really was eight feet tall, assumed Byrne’s role after his death. He also called himself O’Brien, and the two merged in the popular imagination. By the spring of 1783, only a year after his triumphant entry into London, Byrne was in constant pain, his bones cracking under his weight. Newly destitute, robbed of his life savings, he was busily drinking himself to death.

QUICK TAKE Human bodies contain immense genetic, evolutionary, and anthropological evidence. Bodies that are exceptional for their age or physiology are particularly valuable to researchers.

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U.S. law requires the return of Native American remains to their communities, but some researchers argue that the bodies’ scientific potential outweighs their cultural significance.

Some institutions no longer display bodies of unconsenting humans. However, the remains are often stored for future study rather than buried or returned to their communities.

Wikimedia Commons/PD-Art

Surgeon and anatomist John Hunter was an avid collector of biological specimens, including the skeleton of the “Irish Giant” Charles Byrne, whose feet are visible in this portrait (upper-right corner). Prior to his death in 1783, Byrne took steps to ensure that his body would not become a scientific specimen, but his wishes were not honored. Today, researchers struggle with the question of whether to study the remains of unconsenting subjects whose bodies contain scientific value. (Hunter is shown here in an 1813 painting by John Jackson based on a portrait painted from life by Joshua Reynolds in 1786.)

He was 22 years old, and he knew that Hunter wanted his body after he died. The anatomist had offered to pay Byrne a sum of money if he would bequeath him his body. This practice was not uncommon—40 years earlier, the “Irish Dwarf” Owen Farrel had made just such an arrangement with a surgeon. The value of Farrel’s bones, at www.americanscientist.org

least initially, was as a curiosity: They entered the collections of the Duke of Richmond. Hunter’s brother William, who purchased the skeleton at an auction after Richmond’s death, was more interested in Farrel’s abnormally bony cartilage. Byrne knew that if he granted John Hunter’s request, his body would share

the fate of Farrel’s: Hunter would eviscerate it, dismember it, boil it until the flesh came off, and assemble the bones with wires and rods into a skeleton. Byrne refused Hunter’s offer, and took steps to ward off this fate, arranging with friends to seal his dead body in a lead coffin and pay for its transport to the coast for a burial at sea, far from 2024

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Classic Image/Alamy Stock Photo

Wellcome Collection

This circa 1782 advertisement announces the opportunity to view Byrne, the “Irish Giant” (left). After Byrne’s death, Hunter obtained his body as part of his anatomical collection, which became the foundation of the Hunterian Museum at the Royal College of Surgeons in London. For nearly 200 years, Byrne’s skeleton was displayed alongside that of Caroline Crachami, the “Sicilian Fairy” (1896 engraving, right). Although the skeletons are no longer available for public viewing, they remain part of the museum’s collection.

Hunter’s predatory hands. Or perhaps the burial was to be in Ireland. There are many conflicting accounts. The announcement of Byrne’s death in Parker’s General Advertiser in June 1783 noted that “His remains are secured in his coffin, which measures upwards of eight feet four inches [2.5 meters].” Although his friends were “determined to have him carried to Ireland in a few days,” they first offered to show the coffin to the public, for a fee of two shillings and sixpence apiece. The coffin never made it to Ireland nor to the coast. Accounts also differ as to how Hunter obtained Byrne’s body; the London Morning Chronicle declared that Hunter paid 125 guineas, more than £20,000 today (approximately $25,200), for the body. Others claimed he paid £500. Possibly the friends who exhibited the coffin sold the body to Hunter. In any case, Byrne’s next public appearance was his skeletonized feet in Reynolds’s portrait. Hunter declared 156

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that his interest in Byrne was purely scientific. Examining the extremes of nature, as well as normal specimens, gave him insights into its inner workings. He amassed an enormous collection of human and animal skeletons, skulls, and anatomical preparations housed both at his home in Leicester Square and his country house at Earl’s Court, where he also maintained a menagerie. While his collections were primarily for his own research, from 1788 onward he opened his home at Leicester Square for public viewing a few times a month. He put the skeleton of Byrne on display as part of a case depicting the growth of bones. Hunter died in 1793, and in 1799 his anatomical collections, including Byrne’s skeleton, were purchased by the British government and transferred to the Company of Surgeons, which later became the Royal College of Surgeons of England. The College’s museum opened in 1813, and Byrne’s skeleton remained on display there for

the next two centuries. In 1909, a U.S. surgeon sawed open Byrne’s skull and found evidence of the pituitary tumor that caused the release of excessive amounts of growth hormone. Later, DNA was extracted from one of Byrne’s teeth. At some point in the 19th century, another skeleton joined Byrne’s on display. Known as the “Sicilian Fairy,” Caroline Crachami died in 1824 at the reputed age of nine. At the time of her death, she was around 50 centimeters tall—the size of a newborn infant— making her one of the smallest humans ever recorded. The two skeletons survived the Blitz, which destroyed much of Hunter’s collection, but were put in storage in 2017 when the museum closed for renovations. Scientific versus Cultural Value A second story of identity and ownership of a dead body began in the summer of 1996, when some teenagers found a skull along a bank of the Columbia River. The man who had been buried there some 8,500 years ago was tall for his time, at around 1.7 meters, but he was not a giant. His burial was deliberate, with his body laid on its back, parallel to the river and with his head pointed upstream. When his skull even-

www.americanscientist.org

Steve Ringman/Seattle Times 2015

tually emerged from the riverbank, time had already removed his skin and hair, his eyes and tongue. The teenagers who found it assumed it belonged to the victim of a murder and called the police. The nearest town, Kennewick, is near the confluence of the Columbia with the Yakima River to the west and the Snake River to the east, and the waters here are bisected by the McNary Dam. The skull came to the local coroner, who called James Chatters, a local archaeologist, to determine if it belonged to a crime victim. Chatters recognized that the skull was quite old and, judging by its shape, he at first believed it had belonged to a white settler. Returning to the site, he found some 300 bones and fragments: nearly a complete skeleton. Carbon-14 testing on a finger bone initially established its age at around 9,000 years old. The emergence from the muddy shore of these bones—who came to be called either “Kennewick Man” or “the Ancient One,” depending on the speaker—opened a 20-year debate about ownership, heritage, and science. The McNary Dam site where the bones were found is owned by the U.S. government and managed by the U.S. Army Corps of Engineers. The Corps issued the permits that allowed Chatters to find more of the skeleton and, once the age of the bones became clear, the Corps took possession of them. Because they dated from long before 1492, the course of action for the Corps seemed clear. Under the provisions of the six-year-old Native American Graves Protection and Repatriation Act (NAGPRA), if the bones were preColumbian, they were by definition Native American. If the bones were Native American, the Corps was obligated to repatriate them to local tribes. Five local Native American tribes had already claimed Kennewick Man as an ancestor, “the Ancient One.” At this point, only a few months after the discovery of the bones, Kennewick Man was already renowned in the archaeological world. At that time, few bones of such an advanced age, and only one other skeleton, had been found in North America. Emerging technologies challenged accepted theories on the populating of North America, including when it occurred, where it originated, and by which route. New methods of analysis such as CAT scans and 3D modeling helped to reconstruct what skeletal bodies looked like when alive, and stable isotope analysis—which considers the ratios of stable isotopes

At a 2015 press conference, Jim Boyd of the Confederated Tribes of the Colville Reservation called for the return of the Ancient One, also known as Kennewick Man. Some researchers opposed repatriating the remains, arguing that the 9,000-year-old skeleton contained unparalleled evidence of early American life. After a 20-year campaign demanding that researchers comply with the Native American Graves Protection and Repatriation Act (NAGPRA), the remains were returned to the Colville tribes in 2016.

of carbon and nitrogen in bones— reconstructed the diets and the origins of the long-dead. Most exciting was the potential of DNA analysis, which

Ironically, because the Federal court agreed that the identity of the bones could be determined only scientifically, the scientists were freed to conduct studies to determine that identity. was in its infancy in the 1990s. Chatters had just sent a finger bone out for DNA analysis when the Corps ordered him to stop any further testing. A group of anthropologists and archaeologists sued the Corps to prevent repatriation, arguing that the identity of the bones had not yet been determined, and that therefore NAGPRA did not apply to them. They pointed to the need for further study, which the five tribes strenuously opposed, instead calling

for the bones to be buried without further analysis. Ironically—and this case is drenched in irony—because the federal court agreed that the identity of the bones could be determined only scientifically, the scientists were freed to conduct studies to determine that identity. These studies mostly focused on craniometry, the size and shape of the skull, which many believed to indicate a non-Native American identity. Chatters published images of the skull in 1996 and 1997 and identified its shape as “Caucasoid,” an archaic racial classification that some construed as racist. The facial reconstruction Chatters made from a resin cast of the skull, published in Science magazine in 1998, most resembled the actor Patrick Stewart (Chatters admitted that he was a fan of Star Trek). White supremacist groups in the United States seized on the “Caucasoid” label to argue that white Europeans had settled the Americas before any ancestor of modern Native Americans. By then, the bones had been deposited in the Burke Museum at the University of Washington, where they remained securely stored and were never displayed. The 2004 judgment in the lawsuit against the Corps declared in favor of the scientists. The settlement opened the door to a more detailed study of the remains over the next de2024

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Brittney Tatchell, Smithsonian Institution

Emmanuel Laurent / Science Source

Some researchers speculated that Kennewick Man was of European or Asian descent, and therefore his remains were not subject to NAGPRA. Facial reconstructions reflected this bias: A 1998 model drew comparisons to the English actor Patrick Stewart (left), whereas a 2014 reconstruction resembled the Indigenous Ainu people of Japan (right). In 2015, DNA evidence proved that the skeleton was indeed Native American and had belonged to an ancestor of the Colville tribes.

cade, resulting in what seemed to be the definitive account of the bones. Ten years later saw the publication of Kennewick Man: The Scientific Investigation of an Ancient American Skeleton (2014), edited by the anthropologists Douglas Owsley and Richard Jantz. The study described Kennewick Man as relatively tall, “broad-bodied, and massive.” But was he an ancestor of modern Native Americans? Amid an avalanche of data on diet, overall health, and burial conditions, the critical question of identity remained focused largely on the skull. Some anthropologists thought it resembled the modern Ainu of Japan, an Indigenous people who predate the Japanese but whose ancient origins remain debated. Additional analysis suggested that the skull showed the most affinity with Polynesians, indicating a common set of ancestors. This theory in turn fit new ideas of multiple migrations from Asia to the Americas, with some traveling across 158

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the sea and perhaps predating those who came overland from Siberia across the Bering Land Bridge. Owsley and Jantz concluded that “Kennewick Man . . . differ[s] from modern American Indians in systematic ways . . . their difference is mainly genetic and as such carries information about their history and biological affinities,” although the proof they presented was mainly morphological. Throughout the volume, Kennewick Man is referred to as a “Paleoamerican” rather than the more common name of “Paleoindian,” in an attempt to demarcate differing ancient groups. A new reconstruction of his face resembled photographs of Ainu men, with a full beard and lightly tanned skin. A little more than a year after the publication of Owsley and Jantz’s volume, the carefully constructed chain of identification fell apart when the results of DNA analysis showed that “Kennewick Man is closer to modern Native Americans than to any other popula-

tion worldwide.” An article in Nature in July 2015, authored by a team led by evolutionary geneticist Eske Willerslev, then at the Natural History Museum of Denmark, reported the results of the analysis. The team had sequenced the genome of Kennewick Man and compared it with other populations, particularly other Native American populations. The closest relationship appeared with the Confederated Tribes of the Colville Reservation, one of the five tribes who had claimed Kennewick Man as the Ancient One nearly 20 years earlier. The Colville tribes were the only ones to agree to provide DNA samples for comparison. The development of research on what is known as ancient DNA, or aDNA, had progressed rapidly in the decade before Willerslev’s article in Nature. Ancient DNA consists of short and degraded fragments that persist in materials such as bones and teeth, as well as hair, mummified skin, and dental calculus. The first sequencing of aDNA occurred in 1984 from a museum animal specimen, but it took years to overcome the technological challenges to obtaining meaningful results from fragmentary and often contaminated

evidence. Moreover, the interpretation of aDNA evidence required collaboration between bench scientists and social scientists, who had to quash their mutual suspicion and develop a common vocabulary as well as a chain of ownership that minimized contamination. For example, the bones of Kennewick Man had at various times been in a box, plastic bags, and an evidence locker before their arrival at the Burke Museum, increasing their chances of contamination with modern DNA at each stop. Perhaps most important, the analysis of aDNA is necessarily destructive. The sample to be analyzed is reduced to a powder and treated with chemicals that purify the DNA from contaminants, isolate it, and extract and recover fragments. Although improved technology has reduced the size of the sample required, the cultural significance of removing even a small sample from an ancient specimen cannot be ignored. The results of the aDNA analysis fulfilled NAGPRA’s requirement of a preponderance of evidence, allowing the Corps to declare definitively that Kennewick Man belonged to the five tribes who had originally claimed him, and particularly to the Colville. The Corps confirmed what the five tribes had said all along: that the Ancient One was their ancestor. In February 2017, the Burke Museum turned over the bones to the tribes. As required by law, that meant all the bits and pieces, including what remained of the finger bone used for DNA testing, thus precluding any further testing. The Ancient One was reburied in an undisclosed location on the Colville Reservation along the Columbia River. Not Displayed but Not Returned Such a resting place was not to be allowed to the skeleton of Charles Byrne. Calls for the burial of his bones—either in Ireland or at sea—began years before the Hunterian Museum closed for renovations in 2017. These calls intensified during the museum’s closure, with Hilary Mantel taking a prominent role. Every inch of Byrne’s skeleton had been measured and examined. A tooth had been extracted for DNA testing in 2011. Surely, Mantel and other advocates argued, science had learned all there was to learn. “He’s waited long enough,” she wrote in a 2020 email to the Guardian newspaper. A 2011 study published in the New England Journal of Medicine used DNA testing to reveal that the pituitary tuwww.americanscientist.org

mor that caused Byrne to be a giant had a hereditary component. It was not merely a spontaneous mutation, and the frequency of Irish giants was not merely apparent or coincidental but quite real. The giant Knipe twins, with whom Byrne had been depicted, had grown up in a neighboring village to Byrne’s, and by this evidence they were most likely distant cousins. The genetic evidence showed that the giant’s trail went back for generations. Ireland really was a birthplace of giants.

The living give the bodies of the dead— and thus their own bodies—meaning, whether as relics, museum displays, scientific subjects, or buried ancestors. However, this evidence, far from persuading the museum that science had learned all there was to learn, led them to conclude that the bones still had more to tell. The scientists who had examined Kennewick Man would certainly agree with this assessment. DNA analysis and particularly the analysis of ancient DNA has been refined further in the past decade. Unlike Kennewick Man, Byrne has not been buried, although his skeleton was no longer on display when the Hunterian Museum reopened in May 2023. He remains in the museum as Osteo.223, available for future research. The tiny skeleton of Caroline Crachami, Osteo.227, also remains in storage at the museum. These stories affirm that the way the living have treated dead bodies throughout history is never about the dead but about themselves. The living give the bodies of the dead—and thus their own bodies—meaning, whether as relics, museum displays, scientific subjects, or buried ancestors. Their status as colonial subjects made the remains of Byrne and the Ancient One particularly vulnerable to exploitation. In Byrne’s time, certain fields in Ireland were still littered with bones and skulls, the result of Oliver Cromwell’s brutal reconquest of Ireland in the 1650s. Byrne and his contemporaries assumed they owned their own bod-

ies, believing therefore that they could control their disposition after death. Although Mantel portrayed Byrne as a deeply spiritual man steeped in Irish mythology, in fact we know little of his spiritual or emotional life, or of his wider community. By contrast, the transformation of Kennewick Man into the Ancient One owed to the unwavering values of Native American communities who claimed him as their own. However, the U.S. government accepted these values only when science affirmed the claims. Moreover, although the Ancient One has been reburied, forever lost to science, Native American bones and artifacts remain in anthropology departments and museum collections around the world. The values of the community who have demanded the burial of Byrne are more diffuse, and the laws that govern the display of human remains in Britain are loosely interpreted (unless the remains are under 100 years old, in which case they are subject to stricter regulation). Byrne’s bones remain in a storage room, awaiting further tests as the science of aDNA advances. Perhaps scientists will learn more about pituitary tumors from Byrne, and his body, racked with pain in life, will be able to prevent a similar fate for others. In place of the skeleton itself, visitors to the museum can view Reynolds’s depiction of his feet, hanging over Hunter’s mantel. Bibliography Chahal, H. S., et al. 2011. AIP mutation in pituitary adenomas in the 18th century and today. New England Journal of Medicine 364:43–50. Higuchi, R., B. Bowman, M. Freiberger, O. A. Ryder, and A. C. Wilson. 1984. DNA sequences from the quagga, an extinct member of the horse family. Nature 312:282–284. Kakaliouras, A. M. 2008. Leaving few bones unturned: Recent work on repatriation by osteologists. American Anthropologist 110:44–52. Murphy, D. P. 2020. Hilary Mantel calls for skeleton of Irish “giant” to be repatriated. Guardian (October 15). Orlando, L. 2021. Ancient DNA analysis. Nature Reviews Methods Primers 1:14. Rasmussen, M., et al. 2015. The ancestry and affiliations of Kennewick Man. Nature 523:455–458. Science editors. 1998. Kennewick Man realized. Science 279:1137.

Anita Guerrini is Horning Professor in the Humanities emerita at Oregon State University and research professor of history at the University of California, Santa Barbara. This article is adapted from one that appeared in Aeon, aeon.co. Email: [email protected] 2024

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Do You Know Where Your

Increasingly crowded orbits require transparent modeling practices and data exchange. David Finkleman

A

satellite in orbit around the planet moves at 8 kilometers per second. Right now, there are about 9,500 satellites circling Earth, and about three-quarters of them are classified as small satellites— with a mass less than 500 kilograms and possibly as little as a few kilograms. Space is vast, but orbits most useful to us are either geostationary (in which the satellite rotates with the Earth) or within about 1,000 kilometers of the surface. The likelihood of satellites in these orbits colliding with one another or with debris is very small, but the cost and con-

sequences of such a collision could be very large. Although classical mechanics might have led us to believe that orbits never change, in fact there are physical phenomena on many timescales that can change orbits. We must observe satellites and account for all these factors to track where satellites are now and estimate where they might be in the future. How well can we determine where every satellite might be so that we can keep the probability of collision acceptably small? The question has taken on even more urgency, as projects are already under-

way to launch many small communication and observation satellites. The company SpaceX has alone launched more than 5,700 satellites since 2019. There might be tens of thousands of satellites in these networks. Sometimes dozens are launched simultaneously. There are differences of opinion about whether this rapidly growing number of launches will increase collisions. When more than 70 satellites are launched at one time, they are deployed into different orbits, but the probability of one of them being hit by something is necessarily greater

QUICK TAKE Earth’s orbit is getting more crowded, and it will only become more so with the upcoming deployment of megaconstellations of small communications satellites.

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Keeping track of the location of satellites, through direct monitoring or modeling, is designed to prevent collisions, but both methods currently lack precision.

Space debris is often not depicted at an accurate scale, making Earth’s orbit seem more crowded than it is; still, new methods are needed to minimize the threat of collisions.

Satellite Is Tonight?

ESA/ID&Sense/ONiRiXEL

A simulation from the European Space Agency (ESA) demonstrates the potential for catastrophic damage to satellites from collisions in orbit. This simulation depicts space debris striking a satellite, but the potential for collisions in orbit between satellites will be exacerbated by the upcoming deployment of megaconstellations with potentially tens of thousands of satellites.

than if only one satellite was launched. However, these satellites are all quite small, and the consequences would be worse if a big one hit something. So, do we count the number of launches or the number of satellites when calculating risk? We have to determine if a large one counts more toward collision damage risk than a small one, or if the capability of a large one compensates for its size. How does one balance the increased risk of a large-sized satellite with higher capability, compared with the several small satellites it would take to accomplish the same task? Some operators consider the product of the collision probability with the consequences to be most important. www.americanscientist.org

But despite the common belief that a pebble in orbit is going fast enough to disable or destroy a satellite, mass is a major factor. For instance, a pebble could penetrate a solar panel, which encompasses the greatest area of most satellites, with no detrimental effect. The frequency of collisions, although still very sparse, will increase. Those who will own these collections of many satellites see greater opportunity than difficulty. Those who are dedicated to space safety and sustainability worry. From the Ground Up Earth-based instruments, such as the radar and telescope stations in the U.S. Air Force’s Space Surveillance Net-

work, are able to detect satellites (and debris from defunct ones) in orbit, at least most of the time (see figure on page 162). Earth rotates below the satellites, whose orbital periods are mere hours. It might not be possible for a single site to observe a satellite on successive orbits, and several observations are required to estimate orbital parameters. The relationship between satellite and observation site locations can make it so that the satellite might be too far east to observe on one pass and too far west on the next (a situation called a stepover). Occasionally, it’s possible for an observation site not to be able to see a satellite for several revolutions, long enough that external forces change the orbit. The forces include the extent of the atmosphere, nonuniform and everchanging gravity, and the influence of the Moon. 2024

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A

14,000

B

C

number of unique events per month

A: COSMOS 1408 ASAT debris & GPM vs Starlink conjunctions

12,000

B: ICESat-2 conjunctions with various payloads C: TROPICS & Starling vs Starlink conjunctions & Starling constellation internal conjunctions

10,000 8,000 6,000 4,000 2,000

Jan-16 Mar-16 May-16 Jul-16 Sep-16 Nov-16 Jan-17 Mar-17 May-17 Jul-17 Sep-17 Nov-17 Jan-18 Mar-18 May-18 Jul-18 Sep-18 Nov-18 Jan-19 Mar-19 May-19 Jul-19 Sep-19 Nov-19 Jan-20 Mar-20 May-20 Jul-20 Sep-20 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-21 Jan-22 Mar-22 May-22 Jul-22 Sep-22 Nov-22 Jan-23 Mar-23 May-23 Jul-23 Sep-23 Nov-23 Jan-24

0

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NASA’s Conjunction Assessment Risk Analysis team tracks orbital events that produce debris. The team reported that from 2016 to 2020, the incidence of such events was relatively stable. After 2020, because of a rapid increase in launches, events were more frequent. A shows the purposeful Russian destruction of its defunct satellite with an antisatellite (ASAT) missile, which affected the nascent SpaceX megaconstellation, Starlink, and the Global Precipitation Measurement (GPM) satellite network. B and C show other debris encounters involving NASA missions and Starlink.

Instruments on the Earth that can observe satellites and characterize their orbits are sparse, but the space industry is always adding more—many of them now privately owned because their observations are valuable to satellite operators. Nonetheless, we could

never see every satellite all of the time. Government-owned instruments are trusted and objective. Industrial systems might not be, and it is complicated to geographically register and format data for common exchange. However, even with more frequent observations,

Planetary Visions

The U.S. Air Force Space Surveillance Network (red dots) consists of a ground-based system of telescopes and radar stations that monitor satellite locations as they pass overhead. The network does not show stations controlled by other countries or by private operators.

orbit uncertainty does not necessarily diminish, because the observations themselves contain imprecision. Every time we measure anything electrical or mechanical, we get a slightly different answer, no matter how true the instrument is. The answer varies mostly because we cannot make the measurement repeatably. We might initiate the electrical measurement at a slightly different time, or measure distances relative to a slightly different place. Theoretically, instruments might change quantum mechanical states. These realities render all observations imprecise. Sometimes the imprecision is not determined.

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Accuracy and precision are usually misunderstood. The difference is important. Accuracy is concrete—an inch is an inch. Precision is probabilistic. For instance, the global positioning system (GPS) satellites can determine precise position and time, but that is accurate only if we associate it with the terrain. Observing instruments must be calibrated well, establishing their statistical errors relative to a standard measurement. All sources of imprecision contribute to the uncertainty of orbit estimates. The uncertainty is quantified in a statistical measurement called covariance. The covariances of orbit data from diverse sources are essential for fusing them (or combining them consistently). We cannot estimate probability of collision unless we know the statistical uncertainties of all of the orbit data of the collision partners, the covariances. It is best to have metadata associated with each observation. Metadata include background information about the instrument, its covariance, and its data. It is important to note that no single site or observation is sufficient to estimate satellite orbits. We must combine several observations, usually from different sources. The orbital parameters come from observations. If a source were to provide orbit parameters from just its own data, its trustworthiness would be doubtful, and it would certainly disagree with other sources. The U.S. Space Force uses observations only from its own trusted sources. Data from privately held sources, particularly metadata, might be withheld. The

Exolaunch

Private rocket launches, such as this illustration depicting a vehicle sent up by German aerospace company Exolaunch, can now deploy multiple small satellites into different orbits simultaneously. The increased number of deployments necessarily increases the probability of collision.

quality of a private source’s measurements might be deemed a competitive advantage. Even if the fullness of data is exchanged, there is no international authority to certify their credibility. Uncertain data from sparse observations is but one source of estimation uncertainty. Our models of orbital motion must always be incomplete: We disregard some phenomena that we know of, and there are undoubtably some factors we don’t know about. We

can only hope that we have included what is most important. The equations of orbital mechanics cannot be solved exactly analytically; we are unable to write the answer in terms of parameters and inputs. Instead, we must integrate the equations with computers. Computer Models Phenomena that have effects on orbits are on many timescales. Solar emissions and space weather are measured in

If a collision between satellites is projected that may require a propulsion maneuver to avoid, a satellite operator creates a maneuver trade-space plot that shows fuel burn intensity on the x axis versus the time of burn on the y axis; color indicates the resulting probability of collision. Earlier maneuvers (higher on y axis) use less fuel to achieve the same mitigation. However, waiting to observe rapidly changing satellite positions can also indicate that the collision isn’t actually likely, eliminating the need for a maneuver altogether. 0

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An ESA simulation shows how a scattering field of debris is created in the event of a satellite collision. The goal of this simulation was to better understand the dynamics of how collision energy dissipates over time, to more accurately track space debris.

minutes, whereas tides on Earth’s surface or rotation in Earth’s molten core are measured in hours, and lunar gravitation is measured in days. Resolving how much each of these phenomena affect an orbit requires numerical integration, which itself grows more uncertain with each time increment. Numerical integration approximates the rates of change of calculus with finite differences. A finite difference is the

difference between two quantities over a small time interval. In calculus, the theoretical time interval approaches zero mathematically. When the equation for each phenomenon is represented with finite differences in time, we neglect activity more rapid than the time step. Smaller-scale phenomena are manifested as uncertainties, which often grow rapidly as we integrate farther and farther in time. We

T. S. Kelso/AGI

In 2009, the destruction of an Iridium telecommunications satellite in a collision with a defunct Russian Cosmos satellite created a cloud of thousands of pieces of debris that continues to orbit the Earth. This simulation shows this debris as orange and blue dots. Although the debris will decay over time, it must be tracked to prevent further damage. 164

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do not account for what might happen between time steps. The same kind of integration is used to map stars, but stars don’t move perceptibly over many Earth rotations, allowing for more data collection. Satellites move rapidly, so data collection is more difficult and sparser. Equations of orbital motion are like the equations that describe energy and fluid motion. Weather and climate analysis are similar. The equations are nonlinear, meaning their end states don’t always vary in proportion to their initial states. This property means that phenomena that are relatively unimportant initially might dominate eventually. A guitar string is a good example: If we neglect the fact that strings can stretch or break, we can make music. But we know that there are resonances that stretch and break strings when their excitation is large. Nonlinearities cause irreversible dissipation of energy, which is one reason that satellite orbits must change with time. Widely different timescales make numerical integration difficult. Such equations are called mathematically “stiff.” Estimating orbit evolution days or more in the future while keeping track of phenomena that change in minutes might require even better computers than we can imagine. Within that interval, analysts estimate the joint probability that two satellites might be in the same place at the same time using evolving uncertainties, given by the covariances. If covariances are not transmitted, analysts use their experience to judge what they would be. That collision warnings are usually wrong should not be surprising. The systems of equations can have strange evolutions. In some, small changes in initial conditions can cause large, even unpredictable changes in results. Mathematician Edward Norton Lorenz of the Massachusetts Institute of Technology, known for describing the butterfly effect in 1969, developed chaos theory, the oftenmisunderstood field that describes the development of “chaotic” and unpredictable outcomes, and that can explain fractals. He proved that very precise (deterministic) systems that include phenomena over many timescales can become statistical, imprecise, and chaotic. There is a very fuzzy time horizon beyond which we should not advance a model lest outcomes become statistically meaningless. Smaller time steps

Pushing Predictions Despite all of the uncertainties in satellite orbit estimation, analysts regularly propagate the models forward in time to predict satellite locations for years, decades, or even centuries. This analysis is undertaken because it’s the best we can do. Most often, this prediction is done to estimate when and where collisions might occur, despite the great likelihood that such collisions will never happen. Nonetheless, the U.S. Space Force uses such analyses to issue collision warnings, which are called Conjunction Data Messages (CDMs). There were about 1.4 million CDMs broadcast between 2014 and 2018. But there were no collisions. These results were independently confirmed by the French Centre National des Etudes Spatiales (CNES). In 2021, more than 2.7 million CDMs were issued, regarding 247 satellites from 47 different nations. The Journal of Space Safety Engineering, in a 2019 special issue on space traffic management, examined warnings

that were issued by the U.S. Air Force’s Space Command, with the same conclusion. In the issue, there is also recognition that essential data elements, such as actual or approximated uncertainties, are missing from analyses. Only 17 of these millions of warnings led to maneuvers. It is nearly impossible to determine whether these maneuvers made any difference because it is 10,000 times more probable that there would not have been a collision anyway. So far, there has been no collision between active satellites, although in 2009, a telecommunications satellite operated by the company Iridium was destroyed when it collided with a defunct Russian satellite, which was classified as space debris because of it was not operational. This distinct lack of collisions is very strong evidence that virtually all CDMs are wrong. That there weren’t any collisions does not imply that anything done to “avoid” collisions made any difference, because collisions themselves are very improbable. It is not possible to conduct statistics on phenomena we have never seen. We have never perceived an actual collision. There have been too few and with different orbits to constitute an adequate statistical sample. We must rely on using orbit data uncertainties to infer probability of collision for individual events. We cannot estimate well how many events there might be in an interval of time in the future. We generally use seven days as the interval of interest. The lack of reliable CDMs is mitigated by the fact that almost no satellite operators use them as reasons to investigate a potential collision. These operators can keep closer custody of their own satellites than the U.S. Space Force can, and they use their own

A sharp increase in the number of satellite launches has led to more debris in space. Object counts are shown by the year they were launched (left) and the year they are expected to decay (right).

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The International Space Station (ISS) regularly sustains mild damage from impact with orbital debris, but the station performs maneuvers if the likelihood of a predicted large collision is greater than 1 in 10,000.

trusted observations to propagate trajectories. The International Space Station (ISS) is a notable exception, and relies on U.S. Space Force data. It is acknowledged that ISS avoidance maneuvers are done in an abundance of caution and likely make no difference. Where Are They? Given the processes discussed so far, how confidently do we know where satellites really are? Well enough for most satellites over intervals of hours or days. Perhaps not well enough for all of them, or for far in the future. We “lose” some satellites that are not where we expected. Almost all are found relatively rapidly by searching nearby where they were projected to be, but some always remain “lost.” The answer is, it depends, and there is a need to balance risk to high-value resources with the level of concern created by tracking and modeling. David A. Vallado of the Center for Space Standards and Innovation in Colorado has demonstrated the difference between estimated and observed future states of satellite orbits. This difference might

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and more precise initial conditions (or more observations) don’t help. We really don’t know where that horizon is. For weather forecasts, it has been shown that a horizon of about two weeks is as good as it gets. Images of hurricane advancement on a weather forecast map with lines like a cornucopia shows growing uncertainty about the location of the hurricane in the future that better data and more capable computers can’t overcome. (See “In Models We Trust—But First, Validate,” January–February 2023.) For some satellites, this horizon may be a few decades, but for others it is perhaps only a few hours, depending on the frequency, locations, and imprecision of observations, as well as the orbit.

SpaceWorks

The amount of debris in Earth’s orbit is extensive, but most of it is quite small. Although all debris has the potential to cause damage, mass does matter, and small debris is unlikely to cause a collision that results in total destruction of a satellite.

grow to be greater than two satellites’ keep-out ranges—the distance from which a satellite is deemed free of danger from collision, let alone the actual dimensions of each satellite—in a matter of hours. The Reality of Risk In addition to satellites in orbit, there is also debris of varying sizes, from tiny

flecks of paint to entire defunct devices. A tiny object speeding around in orbit is often depicted as highly dangerous, but the ability of such small objects to inflict catastrophic damage is exaggerated. Analogies with the energies of speeding freight trains, and photos of solid blocks of aluminum cratered by small hypervelocity objects, are invalid.

NASA ODPO

Visualizations of space debris orbiting Earth are often misleading in scale, because even tiny debris must be awarded at least one pixel to be visible. Oversized representations of debris give the mistaken impression of more debris than is really there. 166

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We cannot re-create orbital speeds in laboratories. The highest laboratory impact speed is about 5 kilometers per second for a few grams of mass. Solar panels are most of the vulnerable area of a satellite, so impacts on diaphanous solar panels are most likely. But very small objects have punctured satellite solar panels with no noticeable performance effect. Impact on the body of a satellite might be more consequential, but the impactor probably would drive through to the outside. Something like the ISS might leak. Complex electronics within unmanned satellites might be compromised, but it is unlikely that such encounters would be catastrophic. Inaccurate depictions of the space debris environment can mislead perception of risk. We often see representations in which the entire globe is enveloped in a dense cloud of satellites and debris. The circular radius of the Earth is about 6,000 kilometers. In these depictions, if the Earth subtends even half of the picture, the resolution of a modern display is thousands of square kilometers per picture element, or pixel. To show anything, objects must be awarded at least one pixel. Thus, in these depictions, each satellite is approximately the size of a small state. Not until we focus in on the scale of a city block could we show satellites to scale. Satellites and debris are much farther apart, smaller, and less menacing than these illustrations imply. (See “The Dilemma of Space Debris,” January–February 2014.) Self-Monitoring There remains a lot of uncertainty in knowing where a satellite might be in the future. Observational data from which prediction begins is imprecise. Physical models are incomplete. Numerical integration has its own uncertainty; the governing equations could have chaotic behavior. Nonetheless, we do well enough for almost all purposes. However, we aren’t as successful in predicting potential collisions. Data from diverse sources are imprecise to differing degrees, and the imprecision is sometimes unstated. Data are seldom in a common format. But the volume of data must be assimilated coherently to understand best where satellites might be. International cooperation for common formats and efficient communication networks is essential—and extremely difficult. If the observational data from all satellites were fully disclosed, with all

Kongsberg NanoAvionics

A small satellite took this photograph of itself using a camera on a deployed arm (visible at top), the satellite version of a selfie stick. Small satellites are beginning to carry more self-assessment tools such as cameras, which may help them autonomously monitor their own safety in the future.

available metadata, the greater precision could be beneficial to satellite tracking. If an improbable collision occurs, operators should not be forced to fear for their reputations. All satellite operators should work to have a better grasp of what the probability numbers can and cannot tell us. To improve satellite locating in the future, an increasing number of satellites are now hosting the equivalent of aircraft transponders, using radio signals that they bounce back from ground stations to communicate their states. This capacity diminishes uncertainty in ground-based tracking, but it might not improve estimates of upcoming satellite locations. For example, France began using the Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) system in 1990, with which it tracks several research satellites. Broader use could depend on satellite size being able to accommodate a transponder. Nonetheless, it is the satellites themselves that know better than anyone www.americanscientist.org

where they are and what is nearby. If future satellites are equipped with the capacity to be more autonomous in sensing their surroundings, and taking necessary action, they may be best situated to efficiently take care of their own safety on their own. Bibliography Boley, A. C., and M. Byers. 2021. Satellite megaconstellations create risks in Low Earth Orbit, the atmosphere and on Earth. Scientific Reports 11:10642. Finkleman, D. 2011. Requirements and guidance for conjunction assessment. Proceedings of the AAS/AIAA Astrodynamics Specialist Conference, July 31–August 4, Girdwood, AK, paper AAS 11-434. Lewis, H. G., and G. Skelton. 2023. Safety considerations for large constellations of satellites. Proceedings of the Second International Orbital Debris Conference, December 4–7, Sugar Land, TX. Lorenz, E. N. 1969. The predictability of a flow which possesses many scales of motion. Tellus 21:289–307. Pelton, J. N., and M. T. Kezirian, eds. 2019. Space Traffic Management and Space Situ-

ational Awareness: Special Issue. Journal of Space Safety Engineering 6:63–162. Kelso, T. S., and A. Gorski. 2009. Space surveillance: Lessons learned from the IridiumCosmos collision. Proceedings of the AIAA/ AAS Astrodynamics Specialist Conference, Pittsburgh, PA. Kelso, T. S. 2009. Analysis of the Iridium 33– Cosmos 2251 collision. Proceedings of the 10th Advanced Maui Optical and Space Surveillance Technologies Conference, Maui, HI, September 2. Vallado, D. A. 2007. A preliminary analysis of state vector prediction accuracy. Proceedings of the AAS/AIAA Astrodynamics Specialist Conference, August 19–23, Mackinac Island, MI, paper AAS 07-358. Vallado, D. A., and D. Finkleman. 2008. A critical assessment of satellite drag and atmospheric density modeling. Proceedings of the AAS/AIAA Astrodynamics Specialist Conference, August 18–21, Honolulu, HI. David Finkleman was Convenor of the Space Operations Working Group of the International Organization for Standardization, and is an academician of the International Academy of Astronautics and the International Institute for Space Law. He is also Chief Engineer at SkySentry, LLC. He earned his doctorate from the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology. He was Chief Technical Officer of the United States Space Command for nearly 20 years. E-mail: [email protected] 2024

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Discovering the Urinary Microbiome For more than a century, doctors thought urine was sterile. Now, microbiology breakthroughs are revolutionizing diagnosis and treatment of urinary tract infections. Alan J. Wolfe and Linda Brubaker

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or decades, medical students have typically been—and still are—taught that the bladder is sterile, but research over the past 15 years has confirmed what some of us have long suspected: The bladder has a microbiome, a resident community of microbes. This simple fact has profound implications for the most common infection treated in clinics around the world: the urinary tract infection (UTI). More than 400 million people globally are diagnosed with UTIs every year, making up 25 percent of all infections treated. UTIs are most common in people assigned female sex at birth, especially as they get older. In hindsight, it is remarkable that there was a long-standing assumption of urine sterility, given that the bladder is connected to the outside via the urethra, which in adult females is approximately 3.5–4 centimeters in length. Given this easy jaunt for microbes, coupled with the knowledge that the urethra opens into one of the most densely colonized sites in the female anatomy, it is hard to imagine how the bladder could be sterile. In the 2010s, research into microbes in the bladder began to show that UTIs and other lower urinary tract disorders are an ecological problem, just like many other health conditions. Much research is still needed to understand how to improve care for patients, especially those with recurrent UTIs—

when the symptoms recur twice in six months or three times in a year. Nevertheless, new research is already providing important clues that will transform care for patients with UTIs. There is no common understanding of what constitutes UTI symptoms. The clearest example of UTI symptoms might be in a young woman who has had no urinary symptoms at all until she recently started sexual activity, after which she begins to experience urinary urgency, frequency, and pain. All clinicians would agree that these are typical UTI symptoms, and that testing or treatment should be considered. Yet chronic urinary symptoms become more common with age, and urinary urgency and frequency affect many adult women. The common term overactive bladder describes these symptoms, which also may be accompanied by urinary incontinence. These symptoms vary—some days are better; others, worse. It is unlikely that an overactive bladder is caused by a “typical UTI,” although it may be associated with changes in the bladder microbiome. Because the presence of these symptoms could mean several different diagnoses, clinicians rely on tests. However, the standard methods used to test for and diagnose a UTI are based on the disproven idea that the bladder is sterile. In the standard urine culture test used by clinical microbiology laboratories around the world,

urine is collected midstream in a cup and sent to a lab, where it is plated on growth media to see what, if anything, grows. Any microbial colonies that grow are examined. Colonies of species considered to be uropathogenic, such as Escherichia coli, are counted. If their numbers rise above a certain threshold, they are reported to the clinician. Although this test can be useful when considered in the proper context, it often produces a false negative result— meaning it fails to detect uropathogens that should be reported. Another standard approach involves a chemical strip dipped in urine to test for the presence of an infection. The test may detect the presence of white blood cells, bacterial products, or pH. These over-the-counter strips may be used at home or in a hospital laboratory. In 2024, the ineffectiveness of UTI test strips is well-known, yet their use remains common. Patients may be given a UTI diagnosis that is incorrect and prescribed an antibiotic that won’t work, or they may find their treatment withheld because the standard urine culture or test strip results don’t support a UTI diagnosis. The use of test strips coupled with a urine culture is a hard habit to beat for clinicians, because currently there are no good alternatives that are widely clinically available. Overall, the diagnosis and treatment of UTIs have been lacking in utility for

QUICK TAKE One out of four infections treated are urinary tract infections (UTIs), but the standard diagnosis and treatment of UTI symptoms leave many people, especially older women, suffering.

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The standard urine culture misses many uropathogens, yet continues to be used as a diagnostic, because alternatives are not widely available or well understood.

Research on the urinary microbiome since the 2010s is transforming care for chronic lower urinary tract symptoms. DNA sequencing and ecological understanding are key.

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Steve Gschmeissner/Science Source

decades, frustrating patients and clinicians alike. More than half of women will get a UTI in their lifetime, and one in four will experience recurrent UTIs. Antibiotic therapy for UTIs is ineffective in about one in five patients. People with recurrent UTIs experience fear and frustration, dissatisfied with the antibiotics they are prescribed and with the general lack of solutions. And no wonder—UTI symptoms are incredibly disruptive to one’s life. People with UTIs commonly experience frequent urgency to urinate, pain when urinating, and disruptions to their sex lives, as well as other symptoms caused by an inflamed organ. Patients often report that they become hesitant to travel, especially when a bathroom may not www.americanscientist.org

Wolfe Lab

This colored scanning electron micrograph (above) shows large numbers of bacteria cultured from urine. Once thought to be sterile, the bladder is now recognized to have a rich and varied microbiome, including many microbes that are difficult to culture. Urinary tract infections (UTIs) are caused by a range of pathogens—most commonly Escherichia coli but also including a range of lesser-known bacteria. The standard urine culture (left, inset) was designed in the 1950s to detect an E. coli infection in the kidneys and became the conventional diagnostic test for UTIs. However, it misses many uropathogens and even misses some E. coli infections. The expanded quantitative urine culture (right, inset) is a method developed by the authors that captures a broader array of uropathogens by sampling more urine and incubating the cultures for longer under a variety of conditions. 2024

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Risk Factors for UTIs normal

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The factors that make a person more likely to develop a UTI are well-known, but that hasn’t necessarily translated to better care for many people with recurrent symptoms. Many of these risk factors make sense with the emerging picture that recurrent lower urinary tract symptoms represent an ecological imbalance in the urobiome.

be available for long stretches of time. Family members voice frustration that modern medicine has no answers for frail, elderly patients who experience dangerous health conditions associated with recurrent UTIs. With the technological strides made in microbiome research in recent decades, recurrent UTIs have become a solvable medical problem. Research is offering insights into which microbes are beneficial or pathogenic, and how to encourage the growth of beneficial bacteria while discouraging the uropathogens. We and other researchers are developing new standards for UTI diagnosis, treatment, and prevention, with patients’ input taken into account. History of Urine Culture The long-standing dogma that “urine is sterile” dates to the mid-1800s, a time when all bacteria were considered pathogens, and microbiology was in its infancy. Maybe you remember from high school science class the story 170

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about how Louis Pasteur disproved spontaneous generation of microbial life: He boiled two flasks of urine. One he exposed to air and it turned cloudy; the other he sealed and it remained clear. He concluded that microbes did not generate spontaneously, a victory for science. However, later scientists misinterpreted Pasteur’s results. For example, 20 years later, William Roberts, a physician at the Manchester Royal Infirmary in the United Kingdom, began an influential research paper with the following statement: “The fresh and healthy urine is perfectly free from bacteria or other minute organisms.” We do not know how he came to this conclusion. Current evidence shows that many urinary microbes do not grow in urine exposed to air. They require specialized atmospheric and nutrient conditions. Roberts’s statement was then cited widely as evidence of urine’s sterility, and it became accepted knowledge passed down in textbooks to medical

students. Even today, the American Urological Association’s Medical Student Curriculum on Adult UTI states incorrectly, “Urine is generally considered sterile.” The internet is filled with similar incorrect statements, some by authoritative voices. To understand why the bladder was thought to be sterile and why a test with a high false negative rate became the standard for diagnosis, we need to understand the origins of these ideas. The current application of the standard urine culture is far removed from the original intent behind its development. In the 1950s, Edward Kass, a brilliant infectious disease specialist at Harvard Medical School, proposed a simple noninvasive method to detect patients with a kidney infection, or pyelonephritis. Kass compared cultured urine samples from both symptomatic and asymptomatic females and concluded that a threshold of 105 colony-forming units per milliliter could distinguish contamination (meaning bacteria introduced to the urine after urination) from pyelonephritis. Although his method was quite successful at diagnosing pyelonephritis, it has been less successful for diagnosing a bladder infection, also called cystitis. Somehow, Kass’s test became the foundation for the standard urine culture, and it was generalized decades ago as a clinical test for diagnosis of cystitis, without rigorous evidence. Most clinicians consider Kass’s method the gold standard for UTI testing. Nothing could be further from the truth. Multiple studies have shown that the threshold of 10 5 colonyforming units per milliliter alone is insufficient to diagnose clinically relevant cystitis, and recently our team and others have shown that it fails to detect or undercounts many pathogenic microbes. Yet it continues to be used throughout the world. An opportunity to overthrow the “urine is sterile” dogma occurred in the late 1970s and early 1980s, when a physician named Rosalind Maskell became a clinical assistant in the renal unit and public health laboratory at  St. Mary’s Hospital in Portsmouth in England. She observed slow-growing microbes in urine from patients with UTI-like symptoms, but negative results from a standard urine culture. These slow-growing microbes required different growth conditions from those of the standard urine culture. She concluded that the standard

Wolfe and Brubaker, 2019; icons Barbara Aulicino

bladder gut vagina

The vaginal and bladder microbiota share some of the same bacteria, but the gut microbiota are mostly distinct. These data come from samples from women without lower urinary tract symptoms. Oral probiotics can help address UTI symptoms, but their mechanism of action is not well understood. In the graphic above, each axis represents principal components of diversity between genomes of bacterial strains. Each dot represents a strain.

urine culture was insufficient for diagnosis of many urinary disorders. Although others replicated her culture results, her work was dismissed as controversial to the point that a symposium was held to debate “urethral syndrome,” a term used to describe patients with UTI symptoms but negative standard urine cultures. For many, the view that urine was sterile above the urethral sphincter and that these slow-growing anaerobic and microaerophilic bacteria were not urinary pathogens was too strong for them to accept Maskell’s— and even their own—findings. Many reports now agree with Maskell and demonstrate the existence and importance of the human microbiota, enabled by technological advances in DNA sequencing and analysis. Most importantly, this recent work clearly revealed that health depends on the symbiotic coexistence of beneficial microbes and humans, and that disease results, in part, from disruption of the normal state. These breakthroughs set the stage for the discovery and acceptance of the urinary microbiota or urobiome. www.americanscientist.org

The Urobiome Study of the urobiome took off about 15 years ago, as advances in sequencing technologies revolutionized the study of the human microbiome. In 2010, David Nelson of Indiana University and his coauthors published a groundbreaking study using a technique called 16S

same method to compare two urobiome sampling locations: urine collected during voiding and swabs of the urethra, collected from young males. Because the bacteria in both samples resembled one another, they concluded that the microbes of voided urine from males were primarily from their urethra. A year later, our team confirmed the presence of the urobiome in females, and compared urine sampling methods to determine the best balance between procedure accuracy and invasiveness. We also used 16S sequencing

Antibiotic therapy for UTIs is ineffective in about one in five patients. rRNA gene sequencing (or 16S sequencing) that detects bits of genetic material from bacteria. The study compared the types of bacteria in voided urine collected from young males suffering from sexually transmitted infections (STIs) with those without STIs. This research team detected bacteria in all urine regardless of STI status, evidence that the male urinary tract was not sterile. One year later, the same researchers used the

to analyze urine from adult females before they underwent urogynecological surgery. We collected urine using three methods: midstream void, suprapubic aspiration (a needle through the lower abdomen, just above the pubic hair, into the bladder), and transurethral (in-and-out) catheterization. Simultaneously, we obtained a vaginal swab, a swab of the skin where the needle was inserted, and a sham 2024

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surgical subspecialty (doctors prefer and are rewarded financially through procedural interventions) with expertise in testing that can ensure that the cause of recurrent UTI is not urinary tract stones or an uncommon serious disorder, such as cancer

typical urology practice is not set up to provide ongoing care for adult women with recurrent UTI

infectious diseases specialist

especially helpful for very, very sick patients who are hospitalized, including those who are immunosuppressed, as they undergo cancer therapy or transplant procedures

their expertise is typically reserved for patients with significant medical illness due to infectious agents, rather than the chronic ambulatory care needed for most adult women with recurrent UTI

obstetriciangynecologist

general care of women, familiar with pelvic examination and prescribing of vaginal estrogen, a key treatment for postmenopausal women with recurrent UTI

generally refer patients to urogynecologist for cystoscopy and ongoing care (see below)

within obstetriciangynecology, a subspecialty: urogynecologist

can do pelvic examinations and cystoscopy

most urogynecology practices are not set up for chronic UTI care

People with recurrent UTI symptoms often struggle to find satisfactory care. Despite how common this problem is, no specialty area in medicine focuses on it. A primary care provider may refer a patient to a urologist, infectious diseases specialist, obstetrician-gynecologist, or urogynecologist, but all of them have pros and cons. Unfortunately, the patient may simply fall through the cracks of the health care system without ever resolving their UTI symptoms.

needle stick (a needle stick without bladder entry). The sequencing detected microbes in the samples, even though the standard urine culture reported all but one sample to have no microbial growth. The microbes in the catheterized and aspirated samples were similar and most often did not resemble those in the voided sample, which too often looked like the vaginal swab. We concluded that voided samples are often contaminated by genital microbes, and aspirated samples best represent the bladder microbiome. For future studies, we recommended transurethral catheterization for sampling the bladder, because the bacteria in the catheterized urine were similar to those in the aspirated urine, but catheterization is much less invasive. Many reports have confirmed this conclusion. Whereas 16S sequencing could reveal DNA evidence of bacteria in urine, it could not determine if they were alive. To address this issue, several groups designed new experimental approaches. Because many bacteria associate tightly with the urothelium—the cells that line the human bladder—a team 172

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led by the physician James Malone-Lee at University College London collected first-void urine from adults with and without chronic lower urinary tract symptoms, and then concentrated the urothelial cells that are regularly shed into the bladder lumen. They cultured the concentrate under conditions not used in the standard urine culture. This method, which they called sediment culture, detected many bacteria that the standard urine culture had missed, including types that had been reported in the earlier sequence-based studies. A year later, our team reported an enhanced culture method that we called expanded quantitative urine culture. Compared to the standard urine culture, this method uses 100 times more urine, multiple growth media and atmospheric conditions, and twice the incubation time. Adult female research volunteers with and without overactive bladders contributed urine obtained by transurethral catheter. When we compared these two culture methods, most of the samples were reported as “no growth” using the standard urine culture, whereas ex-

panded quantitative urine culture detected bacteria in the vast majority of the samples (see the inset on page 169). We next used expanded quantitative urine culture to show that the standard urine culture misses 50 percent of currently accepted uropathogens. We recently verified this result, conducting a study of adult female research volunteers with recurrent UTIs. Both methods detected typical uropathogens, including E. coli, Proteus mirabilis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. However, the standard urine culture did not detect several lesser-known (what we call emerging) uropathogens, including Actinotignum schaalii, Alloscardovia omnicolens, and Streptococcus anginosus. The standard urine culture even underreported the well-known uropathogens Enterococcus faecalis and Streptococcus agalactiae. The latter, also known as Group B strep, has deleterious effects on newborn infants, and thus pregnant individuals are routinely tested for its presence using the standard urine culture. These and other studies have not only highlighted the standard urine culture’s limitations, but also proven that most of the bacteria detected by 16S sequencing and other DNA-based methods can be cultured and thus are alive. Once we knew that the bacteria were alive, we wanted to know if they caused symptoms. Addressing this issue has not been simple, because many species are detected in both symptomatic and asymptomatic participants. For example, E. coli can be present in adult females without UTI-like symptoms at similar levels as those with UTI. This situation is especially common in elderly females. Early studies observed correlations between urobiome composition and fewer urinary tract symptoms. In one of our earliest studies, we detected many more species in adult female volunteers with urinary urgency and incontinence than those without, using the expanded quantitative urine culture and 16S sequencing. Although some types of bacteria were more common in females without urinary symptoms, many were more common in the cohort with them. More recently, we found that females with lower urinary tract symptoms harbored bacteria that differed significantly from the bacteria found in asymptomatic females, in an expanded quantitative urine culture study of 1,004 adult female research volunteers.

As expected, more volunteers with UTI symptoms harbored E. coli more often and at vastly larger amounts than females without symptoms. Many lesser-known bacteria were also common and abundant in females with lower urinary tract symptoms—albeit less frequently and at lower levels than E. coli—suggesting the possibility that they contribute to these symptoms. A 2021 study led by Young Ho Kim of Soonchunhyang University Bucheon Hospital in South Korea showed that the bacterial communities in adult female volunteers suffering from recurrent UTIs contained many more types of bacteria than those with uncomplicated UTIs. These included both generally accepted uropathogens, and also some bacteria that only now are becoming acknowledged as likely uropathogens. Most of these uropathogens are either underreported by the standard urine culture or not reported at all. The 16S sequencing approach detected bacteria in four times as many of the study’s samples as the standard urine culture. Although much of this research has focused on uropathogenic microbes, learning about beneficial bacteria is also an active area of research. For example, in one of our early studies, we noticed that Lactobacillus crispatus, a typical vaginal inhabitant, was very commonly detected in catheterized urine from adult females without symptoms but not from those with symptoms. We also noted that we rarely cultured L. crispatus and E. coli together. In a collaboration with Tim Bugni’s team at the University of Wisconsin–Madison, we discovered that L. crispatus produces an antimicrobial compound called phenyllactic acid, which is extremely lethal to E. coli and many other uropathogens. Once these more sensitive detection methods were validated, we needed to describe these microbial communities. We decided to call them urotypes, defined by the most predominant bacterial type(s). Asymptomatic (presumably healthy) adult females most often have a Lactobacillus urotype. Bacteria in this group are thought to be beneficial and are often found in the female vagina, fermented foods, and probiotics. Urotypes associated with lower urinary tract symptoms vary. In adult females with UTI-like symptoms, an E. coli urotype is most common, albeit at frequencies considerably lower than the often-quoted statistic that 70–90 percent of UTIs are caused by this parwww.americanscientist.org

ticular bacterium. The reason for this inflated percentage is, of course, the standard urine culture, which is designed to detect E. coli and other fastgrowing bacteria that have no special nutritional or atmospheric requirements. It’s an example of the lamppost effect: If one looks for something only in the easiest places to look (for example, under the light of a lamppost, or in a culture designed to detect E. coli), then one will miss evidence that can be found in other places. Other unhealthy urotypes tend to be predominated by opportunistic pathogens. In contrast to professional pathogens—such as the bacteria that

to illogical or poorly effective clinical strategies for patient care. There is considerable overlap with other common urinary problems, such as overactive bladder and urinary incontinence. Prevention and treatment strategies are taught and implemented with the underlying belief that these urinary problems are not serious health issues; often, nonphysician clinicians follow a protocol for diagnosis and treatment. Every doctor should know how to treat a UTI, but many don’t. Primary care physicians are the first stop for most patients. Patients affected by “typical” UTI symptoms are often given a short (three- to five-day) course of

For most detected microbes, we simply do not know if they are good, bad, or indifferent. cause typhoid fever, the black plague, and cholera—opportunistic pathogens are not invaders from the outside, but rather members of our healthy microbiota. Under normal conditions, these bacteria coexist with us and, in many cases, provide health benefits. But, when they are in the wrong place or under the wrong conditions, they can become pathogenic and cause disease. The opportunism of these bacteria suggests that pathogenicity relates to ecology. Unlike professional pathogens that often cause disease regardless of almost anything else, the pathogenicity of opportunistic pathogens more deeply depends on their environment. In the urinary tract, that includes the rest of the urobiome and the host immune response. Determining what conditions cause these bacteria to go rogue in the urinary tract is now at the forefront of this area of research. Poorly Coordinated Care The long ignorance of the urobiome is a symptom of a more general lack of attention to UTIs and a reluctance to acknowledge how serious and prevalent they are. Patients with recurrent UTIs often fall through the cracks of the health care system. Despite the millions of people dealing with urinary discomfort, significant scientific knowledge gaps exist that lead

oral antibiotics, and their symptoms resolve quickly without recurrence. Many clinicians begin treatments without testing. When pretreatment testing is performed, and the antibiotic is started before test results come back, at least there is some insight into next treatment steps if symptoms persist. Another serious downside of treatment without testing is the risk of promoting microbial resistance to antibiotic therapy. This risk is appreciated for many health conditions, but it is often discounted for initial UTI care due to the perception of high rates of clinical success. When symptoms do not resolve or when they recur (sometimes frequently), primary care physicians typically seek consultation from a variety of subspecialists, including urologists, urogynecologists, and infectious disease colleagues. The choice of specialist isn’t easy, though, because no specialty “owns” UTI (see the table on page 172). Because the urinary tract is involved, it makes sense to think of urology. However, urology is a surgical subspecialty, so the typical urology practice is not set up to provide ongoing care for chronic conditions, such as recurrent UTIs. The urology evaluation of a patient with recurrent UTI prioritizes testing that ensures the cause is not urinary tract stones or a 2024

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Courtesy of Michelle Seu

UTI Detection Methods

Detecting pathogens in the lower urinary tract can be done using culture-based or DNA-based methods. The standard urine culture typically plates 1 microliter of urine on two different media, with incubation in air at 35 degrees Celsius for 24 hours. The expanded quantitative urine culture plates 100 times more urine on several different media, with incubation in several different atmospheric conditions at 35 degrees Celsius for 48 hours. Three other methods rely on DNA detection rather than culturing. Amplicon sequencing involves amplification of a specific gene sequence—for bacterial detection, typically a portion of the 16S rRNA gene. This method can detect only bacteria and is a simple analysis. Shotgun sequencing does not involve amplification, but rather sequences all the DNA in a sample. Thus, it can detect bacterial, fungal, viral, and human DNA, but it is expensive and the analysis requires more time. By contrast, multiplex polymerase chain reaction (mPCR) is a targeted approach that can detect only specific microbes (bacteria, fungi, or viruses), making it the quickest and cheapest of the genetic methods.

rare serious disorder, such as cancer. Once the patient undergoes imaging and cystoscopy with reassuring findings, the surgically oriented subspecialist is unlikely to engage in meaningful ongoing care. A patient with recurrent UTIs might also consult an infectious diseases specialist. These specialists take care of very sick patients, including those who are immunosuppressed as they undergo cancer therapy or transplant procedures. They served as the front line during the COVID-19 pandemic, especially in the early months. The expertise of these specialists is typically reserved for patients with significant medical illness due to infectious 174

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agents, rather than the chronic ambulatory care of recurrent UTIs. Women affected with recurrent UTIs might also consult with an obstetriciangynecologist. Within this broad field, the surgical subspecialty of urogynecology and reconstructive pelvic surgery has special relevance. These physicians can do pelvic examinations and cystoscopy, although most urogynecology practices are not set up for chronic UTI care. Thus, despite these various subspecialists’ concern for their patients, individuals with recurrent UTIs often fall through the cracks and receive poorly coordinated care, suffering indefinitely with chronic symptoms. Without a doubt, these patients deserve better—

better prevention, diagnosis, and treatment—based on modern scientific knowledge. Finding little help from their health care providers, patients with recurrent UTIs often explore over-the-counter, unproven interventions. In the absence of sound strategies, they frequently rely on home UTI testing strips and adopt a wide variety of unhelpful or even potentially harmful self-treatment behaviors. Multiple unregulated supplements are popular, including anything with cranberry, as well as herbal remedies of various compositions. Patients may try to help themselves with “good” bacteria, sometimes putting food products such as yogurt into their vaginas. Many find that, no matter what they try, their UTI symptoms recur. Developing New Tests and Treatments Assessment of the urobiome can now become part of improved UTI diagnosis and treatment. Despite the known shortcomings of the standard urine culture, clinicians are not ready to stop using it—mainly because there is no consensus on a replacement test. Although clinicians should not consider the standard urine culture to be the gold standard, because of its high false negative rate, it could still be a useful tool if clinicians understand its limitations and have a clear plan to properly interpret the results. The standard urine culture is widely available in most clinical laboratories. Preliminary results are available in 24 hours, with final results in 48–72 hours, depending on the findings for that specimen. Because this test is good at detecting E. coli, it is an important first step in UTI diagnosis. If the test comes back positive, an antibiotic treatment is warranted—as long as the clinician understands that it does not mean E. coli is the main or only bacterium causing symptoms. Even more important is correct interpretation of a “no growth” result. A negative result does not mean that the urine is sterile, nor that there is no uropathogen infection. It simply means that the clinical microbiologist did not detect a known uropathogen above the commonly accepted threshold. The standard urine culture is also useful in some less common clinical situations, such as cases with patients whose medical history warrants heightened risks associated with antibiotic use, including patients who have had bowel infections with Clostridioides difficile.

Antibiotic use should be minimized in cases without reasonable evidence of its efficacy. For example, some patients have chronic urinary pain of unknown cause. When these unfortunate patients have symptom flares, resorting quickly to antibiotics is ill-advised and generally causes more harm than benefit. When the clinician is uncertain about whether urinary symptoms are UTI-related, standard urine culture testing may help inform decisions about antibiotic use. Alternatives to the standard urine culture—besides dipstick testing, which is decidedly worse—include culture-independent methods that have been commercialized and are available to clinicians and patients directly. As a group, these tests have the capability of detecting many more microbes than the standard urine culture and, in some cases, doing so much more quickly. However, the mere detection of bacterial DNA does not necessarily equate with a clinical infection that endangers human health. Clinicians who order these tests must interpret the results properly so as to avoid mistreatment or overtreatment. Culture-independent methods include 16S sequencing, shotgun metagenomic sequencing, and multiplex polymerase chain reaction (mPCR). Like any method, sequencing of the 16S rRNA gene has both advantages and disadvantages. If designed properly, it can detect the presence of all bacteria, including those that cannot be or are not typically cultured, even bacteria that are present in extremely low numbers. The downside is twofold: First, for most bacteria, the test cannot distinguish between closely related bacteria; second, the test can detect only bacteria. The first is problematic because two closely related bacteria can be very different in their ability to cause disease. The second is problematic because it cannot detect fungi (such as Candida), viruses, and other nonbacterial microbes. By contrast, shotgun metagenomic sequencing can do both. However, because this test sequences all DNA, including the patient’s DNA, the data analysis requires greater time and expertise, and it is more expensive than 16S sequencing. Efforts to resolve many of these problems are underway (and are likely to succeed), but these technical fixes do not solve the larger problem: For most of the detected microbes, we www.americanscientist.org

simply do not know whether they are good, bad, or indifferent. What should a clinician do if the sequencing report comes back with 200 different types of bacteria, of which they have partial understanding of only a handful? The third culture-independent method is mPCR, which offers a targeted approach, whereby a select group of microbes (bacteria, fungi, or viruses) can be detected. The downside is that mPCR can detect only the targeted microbes. The upside is that it can be quick, relatively inexpensive, and expanded to include other microbes. Thankfully, a growing number of groups are developing testing that will speed up diagnosis, improve accuracy, and hopefully facilitate better UTI care. For now, patients with difficult-to-solve and persistent symptoms should seek out clinicians who are knowledgeable about this evolving diagnostics landscape. Breakthroughs can happen quickly! Patients can advocate for themselves by requesting that a clinician order sequencing of their urine. As long as the clinician and patient have a shared understanding of the goals and limitations of such testing, there is no reason to withhold it. This approach can be useful to see two things: what’s there, as well as what’s not there. Young, otherwise healthy women often have communities of lactobacilli, a group of beneficial microbes, in their urine. Repetitive antibiotic treatment can wipe out this community, likely increasing their vulnerability to subsequent UTIs. In addition to looking for “uropathogens,” clinicians and patients should use these tests to see if they have lost the beneficial community members. If a beneficial lactobacilli-predominant community needs to be restored, several steps can help. First and foremost, avoid further antibiotic use if at all possible. Second, use a whole-foods, plant-based diet to help restore the gut microbiome. Evidence-based studies demonstrate the utility of oral probiotics for establishing and restoring health in patients whose gut microbiome has become disrupted. Finally, avoid putting things into the vagina that are not proven to restore the urobiome. Although putting yogurt in the vagina may seem like an intuitive solution since this food is high in lactobacilli, studies show it is ineffective. Patients using oral probiotics may not fully resolve their issues. There is still much research needed to fully understand what affects the urobiome,

including hormone changes, pelvic floor dysfunction, and inflammation that is not caused by uropathogens. To treat changes that occur when estrogen levels plummet following menopause, low-dose transvaginal estrogen is a simple, effective therapy with strong evidence for UTI prevention. Recurrent UTIs are treatable, and affected patients deserve thoughtful consultation with clinicians who are knowledgeable about the evolving science in this area. With the new scientific evidence about urinary health, diagnostic methods, prevention, and treatment strategies should be rigorously evaluated using patient-centric outcomes. Although there is still much to learn, progress is underway. Bibliography Brubaker L., T. C. Chai, H. Horsley, R. Khasriya, R. B. Moreland, and A. J. Wolfe. 2023. Tarnished gold—the “standard” urine culture: Reassessing the characteristics of a criterion standard for detecting urinary microbes. Frontiers in Urology 3:10.3389/fruro.2023.1206046. Deen, N. S., A. Ahmed, N. T. Tasnim, and N. Khan. Clinical relevance of expanded quantitative urine culture in health and disease. Frontiers in Cellular and Infection Microbiology 13:1210161. Finucane, T. E. 2017. “Urinary tract infection”— requiem for a heavyweight. Journal of the American Geriatrics Society 65:1650–1655. Jung, C., and L. Brubaker. 2019. The etiology and management of recurrent urinary tract infections in postmenopausal women. Climacteric 22:242–249. Kline, K. A., and A. L. Lewis. 2016. Grampositive uropathogens, polymicrobial urinary tract infection, and the emerging microbiota of the urinary tract. Microbiology Spectrum 4:10.1128/microbiolspec.UTI-0012-2012. Neugent, M. L., N. V. Hulyalkar, V. H. Nguyen, P. E. Zimmern, and N. J. De Nisco. 2020. Advances in understanding the human urinary  microbiome  and its potential role in urinary tract infection. mBio 11:e00218-20.  Onywera, H., R. Chambuso, D. J. Benjamin, E. E. Hilt, and K. Thomas-White. 2024. Editorial: An outlook on urobiome: Advances in understanding the role of urobiome in urological health and disease and its potential in biotherapeutics. Frontiers in Urology 4:1380340. Wensel, C. R., J. L. Pluznick, S. L. Salzberg, and C. L. Sears. 2022. Next-generation sequencing: Insights to advance clinical investigations of the microbiome. Journal of Clinical Investigation 132:e154944. Alan J. Wolfe is a microbiologist at the Stritch School of Medicine of Loyola University Chicago. Linda Brubaker is a clinical professor in the department of obstetrics, gynecology, and reproductive sciences, division of urogynecology and reconstructive pelvic surgery, at the University of California, San Diego. Email for Wolfe: [email protected] 2024

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Connected Behaviors Animals use complex social networks to disseminate practices that are distinct to their geographic and cultural groups. Lee Alan Dugatkin

A

core tenet of evolutionary biology is that for the process of natural selection to act on a behavioral trait, three things must be in place. First, there must be different behavioral variants in a population. For example, if the behavior is mate choice, then some animals might prefer colorful, risktaking mates and others might prefer drabber-colored, risk-averse mates. Without behavioral variation, there is nothing for natural selection to select on. But variation itself is not enough for natural selection to act: That variation has to map onto reproductive success, even indirectly. If behavioral variation does not translate into fitness differences, it does not lead to evolutionary change. And, finally, behaviors have to be transmitted, with a reasonably high degree of fidelity, from generation to generation. Without a system of inheritance, any fitness differences associated with behavior in one generation are washed away in the next. When Austrian monk Gregor Mendel’s experiments on peas (among other things) were rediscovered in the early 1900s, it became clear that genes are one means of transmitting traits, including behavioral traits, across generations. Indeed, for the next 50 years or so, evolutionary biologists and animal behaviorists assumed genes were not only one way to transmit traits across generations—they were the only way. But in time, ethologists began to learn of another transmission system. In their studies of the foraging behavior of Japanese macaques in the 1950s and 1960s, primatologists Shunzo Kawamu-

ra of Osaka City University and Masao Kawai of the Japan Monkey Center in Aichi found that behavior could be passed down across generations in nonhumans not only genetically but also via cultural transmission. What’s more, cultural transmission occurs not just between generations, from parent to offspring, but also within generations, from peer to peer. Starting in the 1950s, Kawamura and Kawai studied a troop of Japanese macaques (Macaca fuscata) who lived on Kǀjima Islet (then called Koshima Islet) in Japan. The researchers threw sweet potatoes and wheat on the sandy beach so the monkeys would get used to the presence of humans. When one macaque, whom they named Imo, was about a year old, she began to do something no macaque on the island had ever been seen doing: She washed her sweet potatoes in water before she ate them, dislodging all the sand and making the sweet potatoes all the tastier. If Imo were the only one who did this, her innovation would have died with her. Instead, many of Imo’s peers and relatives learned the skill of potato washing from Imo via cultural transmission: by watching her clean her potatoes and trying it themselves. Imo’s standing as a cultural icon among the macaques on Kǀjima only grew stronger. When she was four, she found a better way to handle the wheat the humans threw on the beach. Wheat and sand mixed together are edible, but not especially appetizing. Imo came up with a novel solution to that problem too: She tossed her wheat and sand mixture into the water. The sand sank

and the wheat floated. This innovation is a bigger deal than it sounds, because primates virtually never let go of food once they have it in their hands. But to get the sand off, Imo had to release the wheat, and that’s what she did. And as with the sweet potatoes, Imo’s troop mates learned this new trick from her. More than 70 years later, long after Imo’s death, macaques on Kǀjima Islet still wash their sweet potatoes and clean their wheat, and they, and we, have Imo to thank for it. Kawamura and Kawai didn’t use social network theory to understand how Imo’s foraging innovation spread through her group, for the simple reason that social network theory per se didn’t yet exist. But many decades later when Janet Mann was studying culture and tool use in bottlenose dolphins in Australia, it did. Passing on New Behaviors Tool use does not necessarily involve crafting wheels or gears—a definition that almost guarantees it will be seen only in humans—it simply means shaping an object to serve some function. New Caledonian crows (Corvus moneduloides) extract insects from under tree bark using tools constructed from twigs whose leaves have small, sharp barbs running along their edges. Insects react and grab the inserted twig, and the crows pull out the twig tool and eat whatever is clamped on. Novice crow toolmakers begin by constructing simple tools, and as they mature, they start to build more complex ones. New Caledonian crows can even build tools from multiple parts, and

QUICK TAKE When an animal develops a new skill, others in its group may start copying what they see. This behavior may then spread through social networks.

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It is often difficult for researchers to distinguish between the ways that cultural transmission and genetic transmission shape animal behavior.

Social network analysis provides a window into the dynamics of social systems and can enhance researchers’ understanding of how natural selection shapes animals’ behaviors.

Nature Picture Library/Alamy Stock Photo

Macaques on Kǀjima Islet in Japan wash sand off their sweet potatoes before eating. This behavior was first observed in 1953 when a young female began the practice, which was then picked up by others in her community. More than 70 years later, the macaques of Kǀjima still wash sand from their food and pass the behavior on to their peers and offspring. These observations support the idea that some animal species share behaviors through cultural networks that are specific to their locations and circumstances.

remarkably they safeguard their best and favorite tools to reuse. Tools solve problems. For bottlenose dolphins (Tursiops aduncus) in Shark Bay, Australia, the problem centers on poking and probing the sand with their snouts to scare up fish such as spothead grubfish (Parapercis clathrata) from the bay bottom. It is anything but pleasant pounding your snout betwixt and between the rocks down there, so a small fraction of dolphins in Shark Bay, primarily females, pick up a basket sponge using their snout, wiggle that snout snuggly into the sponge, and use it to cushion the www.americanscientist.org

blow of probing the rocky bay bottom, effectively turning another organism into a tool. Shark Bay females take the choice of sponge seriously, often spending 10 minutes finding just the right size and shape to fit their snout, and then swimming to their favorite hunting ground along channels between 8 and 14 meters deep. If a dolphin “sponger” does shake loose a bottom-dwelling fish hiding in the sand, they toss the sponge off and chase their prey. When they are done with that, if the sponge was a particularly good fit, they go back and retrieve it for further use.

Shark Bay, which is near the conservation park Monkey Mia, sits on the west coast of Australia, about 850 kilometers northeast of Perth. The bay is huge, covering 13,000 square kilometers, with an average depth of about 9 meters, and is home to not only more than 1,000 bottlenose dolphins, but also 16,000 dugongs (Dugong dugon), a marine mammal whose closest living relative is the manatee. Within its waters, it also has the world’s largest seagrass banks, and the stromatolite fossils at Hamelin Pool Marine Nature Reserve in the bay date back almost three billion years. And, of course, Shark Bay is home to many sharks, some of whom feed on dolphins. Since the Shark Bay Dolphin Project began in 1984, team members have gathered data on more than 1,500 bottlenose dolphins. Researchers have amassed a giant dolphin mug shot book 2024

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age year

1–1.5

2–2.5

1953

Imo

Semushi

1954

Uni

1955

Ei

Nomi

1956

Sasa

Jugo

1957

Hama, Enoki

3

5

6

adult

total number of monkeys

Eba

3 1 3

Kon

4

Sango, Aome Harajiro

Nami

Zabon, Nogi

1958

4

2

total

6

5

1

2

1

2

17

ƃ Ƃ

2

3

1

0

0

0

6

4

2

0

2

1

2

11 Adapted from Kawai, 1965

Researchers first observed Imo washing sand from sweet potatoes in September 1953, when she was 1.5 years old. Two more macaques quickly picked up the practice: a young male named Semushi and an older female named Eba (females are labeled in green and males in black). From there, sweet potato washing behavior spread from mother to offspring and between playmates, which is why it grows most quickly among younger macaques. By 1958, 17 out of 30 monkeys, representing 56.7 percent of the troop, had acquired the behavior.

identifying individual dolphins based not only on sex, but by using fin shape, as well as the shape of scars, often from shark bites, on the fin and body. Even before sponging behavior was discovered at Shark Bay, Janet Mann was there studying the dolphins. Mann is now a professor of biology and psychology at Georgetown University, but in 1988 she was a PhD

some undergraduate work on mother– infant interactions in baboons at Amboseli Park in Kenya, Smuts asked her to step in and help with the dolphin work, which Mann was more than happy to do. Mann was part of the Shark Bay research team that first documented sponging behavior in 1995, and for almost 30 years, she and her colleagues

Nonspongers may have had more connections in the network, but spongers were forming cliques within that network, preferentially interacting with each other rather than with nonspongers. student at the University of Michigan, working with animal behaviorist and primatologist Barbara Smuts. Smuts had become interested in the mother– calf interactions in the Shark Bay dolphins. One of Smuts’s assistants on the dolphin project canceled at the last minute, and because Mann had done 178

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have diligently been piecing together how this behavior has spread along social networks to a subset of dolphins in the bay. As in the literature on human culture, in animal behavior literature, one of the defining features of culture is that it differentiates groups from one another: “I was very much interested . . .

in whether the dolphins had a concept of ‘this is the way we do things and it’s different from the ways others do it,’” Mann says. “Does that bind them together? Social network analysis lets you get at this with a mathematical method.” Fortunately, Lisa Singh, a computational computer scientist at Mann’s home institution, Georgetown, was already working with Mann to develop a custom database for the dolphins at Shark Bay. Singh also had experience working with social networks, and soon she, Mann, and their collaborators were looking at data on culture and sponging behavior from a network perspective. When Mann and her colleagues began their social network analysis, they knew quite a bit about sponging behavior and spongers in Shark Bay. They were certain sponging worked as a foraging technique, not only because they could, if conditions were just right, see the dolphins sponging as they watched from their boat, but because they did some sponging themselves. They’d dive in an area that sponging dolphins liked and record the dolphins. Then, they’d do a second dive at the same spot, and while some divers recorded, others probed the bottom wearing sponges on their hands. When they compared the videos, they were amazed by just how many bottom-dwelling fish were stirred up when human spongers shook up the otherwise safe world of those fish. Mann knew spongers tended to be female. Although the occasional male puts a sponge on and probes the bay bottom, for the most part males are more interested in forming coalitions and alliances that help them secure mating opportunities than they are in specialized tool use. Mann was also aware that except for a dependent calf who might be swimming beside her mother, when female spongers foraged, they did so alone; but dolphins who were not spongers tended to search for food in groups. She also knew that spongers always had a mother who was a sponger, and she hypothesized that young dolphins were copying—a type of cultural transmission—their mother’s sponging behavior. Cultural transmission from parent to offspring can be hard to nail down because it looks a lot like genetic transmission of behavior from parent to offspring. In both, something is passed down from a parent. In cultural transmission, that something is a skill, like how to forage using a sponge; in the ge-

Courtesy of Ewa Krzyszczyk

Some bottlenose dolphins in Shark Bay, Australia, use sponges to protect their snouts when searching for fish among rocks. The majority of these “spongers” are females, all of whom learned the behavior from their mothers. Dolphins who do not use sponges tend to have wide social networks, whereas those who use sponges have smaller but more tightly knit cliques that consist primarily of other spongers. The difference in network size may in part be because nonspongers forage in groups, whereas spongers tend to forage alone.

netic transmission, it is genes associated with the behavior that are transmitted across generations. Behavioral ecologist Michael Krützen led a team of researchers, including Mann, who employed molecular genetic tools to rule out genetic transmission. They found that sponging is indeed a culturally transmitted trait from mother to offspring. What Mann didn’t know was whether female spongers were somehow networking with one another. Recall that sponging is a solitary affair, except for a female who sometimes has a dependent calf with her, which means that spongers are not networking while they sponge. But sponging behavior takes up only a small part of a dolphin’s day. Perhaps adult female spongers network with one another when they’re not sponging? “Spongers [sometimes] carry their sponges and will join with other spongers with sponges on,” Mann says. “They aren’t foraging then, just hanging out.” What’s more, females who use a sponge once tend to specialize in sponging, which means that if you are a sponger, even if another sponger isn’t wearing a sponge when you see her, as long as you’ve seen her with a sponge www.americanscientist.org

on at some point, you can be fairly certain she is still a sponger. To construct bottlenose association networks, Mann and her team looked for who was swimming near whom when dolphins were not foraging. Dolphins were considered to be associating if they were within about 10 meters from one another or were linked to each other through another individual using the same 10-meter rule. Mann used historical association patterns of 36 spongers and 105 nonspongers gleaned from almost 15,000 surveys that detailed where dolphins were between 1989 and 2010, what they were doing, and which dolphins they were swimming with. What the social network analysis of these 141 dolphins revealed was that nonspongers were better connected than their sponger counterparts. Nonspongers had more associates and stronger bonds with those associates than did spongers. Nonspongers also had more friends and friends of friends. Part of the deeper connectedness of nonspongers in the network is due to their tendency to forage in groups: Although foraging behavior was not part of the network analysis

per se, nonspongers probably spend more time around others in anticipation of group foraging events. The one major social network metric for which spongers had higher values than nonspongers was the clustering coefficient, which, among other things, measures cliquishness. Nonspongers may have been more connected in the overall network, but spongers were forming cliques within that network, preferentially interacting with each other rather than nonspongers. But why? What were spongers getting from membership in a clique? If sponging is a solitary affair, why bother hanging around other foragers? Mann and her colleagues think at least part of the answer is that although a sponger always learns the skill of sponging from its mother, and only its mother, it may be that spongers can get another bit of important spongerelated information—namely, where the good sponges are located—from swimming around with others in their social network clique. Sharing Hunting Techniques Remarkably, dolphins are not alone in using sponges and in utilizing networking as a means for using them effectively. Chimpanzees also use sponges, but they network in a very different way than bottlenose dolphins. But rather than focusing on sponges, let’s peer in on the culture network of a cetacean relative of those bottlenose dolphins. “I was one of those kids,” Jenny Allen recalls, “that said I was going to grow up to work with whales, and everybody kind of went ‘Yeah, OK, but, like, you’re going to get a real job eventually.’” Eventually she did get a real job— working, as she predicted, with whales. As an undergraduate, Allen studied marine biology and landed an internship at the Whale Center of New England in Gloucester, Massachusetts. Soon she was spending her time on boats, studying humpback whales (Megaptera novaeangliae) in the Gulf of Maine’s Stellwagen Bank National Marine Sanctuary, about 50 kilometers southeast of the Whale Center. When she graduated, Allen got a full-time position at the Whale Center and continued her work along Stellwagen Bank, watching the magnificent creatures she so loved. Whale research can be tricky, as it often involves a deep tie with ecotourism and whale-watching expeditions. Allen had connections with 2024

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New England Aquarium

Humpback whales use bubble feeding to capture small fish, as seen in this 2022 photograph from the New England Aquarium’s aerial survey team. The whales swim below a school of fish such as herring or sand lance and blow a ring of bubbles to contain their prey; they then lunge through the bubble net as it reaches the surface and catch the fish in their open mouths.

whale-watching companies in the area, and she’d go out with them as an onboard naturalist. She’d narrate the adventure for the 100 or 200 people on the boat, and, in return, she and her assistant were permitted to gather basic information on the whales, including their feeding behavior. They would also take photos, focusing on a whale’s tail—the pattern on the tail is the equivalent of a whale fingerprint— and comparing it with the book full of tail shots they had with them. Usually, the arrangement that Allen had with the captain of a boat worked well, but at times it could be a delicate balancing act. On a day when a ship wasn’t encountering all that many whales, Allen might be ready to move on after 15 or 20 minutes with a whale 180

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they did encounter. But she would often have to spend time trying to persuade the captain, whose job it was to maximize the time passengers on board could spend with the whales they paid good money to see, that they should indeed move on and hope they would encounter another whale. Unless it was just the right captain, in just the right mood, the ship stayed perched in front of the whale who was a sure thing. Standing on deck, Allen was often transfixed by a strange behavior that seemed to be spreading across the population of the 1,300 whales she was studying. Whales in the Gulf of Maine (and elsewhere) had long been known to use a hunting technique called bubble feeding, in which a whale dives 20 meters below the surface and gives

off five or six blasts of breath around a school of prey fish. These bursts of air create a bubble ring underneath and around the prey, and when the bubble ring reaches the surface, the whale crashes through it, grabbing a meal as it does. But all of that wasn’t enough for one humpback whale, who sometime in 1980 added a new twist to the bubble feeding sequence. Right before diving to commence a bubble feed to capture a school of fish, that whale slapped its tail on the water surface, in what has been dubbed lobtailed feeding. Soon, a few other whales were doing the same—though the number of slaps at the water surface varied from whale to whale—and by the time Allen was watching in the early 2000s, nearly 40 percent of the whales were using lobtailed feeding. It seemed to Allen that the lobtailing was spreading through whale networks via cultural transmission: Naive whales who spent time with lobtailers seemed to learn this

new tradition by observation. Still, she knew that she couldn’t be anything close to sure of her hypothesis based solely on her observations. Allen’s interest in the role that social networks might play in the spread of lobtail feeding via culture began in 2010 when she entered the master’s program at the University of St. Andrews in Scotland. There, she worked with networkmodeling guru William Hoppitt and with Luke Rendell, an expert on culture in animals. “Look, do you have any projects that would make a good master’s thesis?” Allen asked Rendell and Hoppitt. “[Because] if not, I have access to this dataset—maybe we [could use] that?” Allen had kept on good terms with the Whale Center, and the dataset she was referencing was brimming with information on lobtail feeding in humpbacks in the Gulf of Maine since 1980. Fortunately, Hoppitt was developing some new social network models and had not yet had the chance to apply them to a wild population or to a dataset as massive as the one Allen had access to, and he was excited to do so. Rendell, who knew a great opportunity to study cultural transmission when he saw one, was keen on the idea as well. Allen’s thesis involved getting the nearly 30 years of data on lobtail feeding at Stellwagen Bank into a form that could be used in a social network analysis. That wasn’t easy. Over the course of three decades, that data had been collected by dozens of different people, with varying degrees of expertise on foraging behavior in humpbacks. “The [observer] didn’t necessarily say, ‘This animal was lobtail feeding,’” she notes, “[but] because I could speak the language of that data collection .  .  . I [could] say, ‘Oh, this sequence of behavior is lobtail feeding.’” Allen searched through 73,790 timetagged whale-sighting records, involving 653 individuals, each of whom had been seen at least 20 times. She coded a whale with a zero if, up to that point in time, it had never been seen lobtail foraging, or with a one if it had been seen lobtail feeding at any point in the past. In addition, for records involving multiple individuals, Allen noted which whales were found together. Even after all that coding was complete, there were still technical hurdles. The dataset was so large that the computer model Hoppitt had built couldn’t handle it all and crashed. But Hoppitt was up to the challenge and made the necessary www.americanscientist.org

Arturo de Frias/Alamy Stock Photo

In 1980, a humpback whale in the Gulf of Maine added a new behavior to its bubble feeding technique: Before diving down to create a bubble net, the whale slapped the surface of the water with its tail one to four times, a practice known as lobtailing. The behavior spread through the local humpback whale community and is still prevalent among whales in the region.

adjustments, and soon the data and the model were syncing up. If whales who were naive to lobtail foraging picked up this technique by watching lobtailers—that is, if lobtailing was spreading through the whale social network via cultural transmission—

in fact what the nearly 74,000 records were showing. What Hoppitt’s model did was compare the probability that a naive whale was learning how to lobtail by observing lobtailers versus the probability that it somehow learned lobtail feeding

By the early 2000s, nearly 40 percent of the whales were using lobtailed feeding. Naive whales who spent time with lobtailers seemed to learn this new tradition by observation. then, as a general rule, lobtailers should be seen associating with lobtailers. To see why, imagine a group of five whales who tend to spend time together. Suppose three of the whales are lobtailers and two aren’t. If the two naive whales learn lobtail foraging from the others, then the next time that group of five whales is observed, and every time after that, they will all be lobtailers. The social network model that Hoppitt built was designed to ask if this scenario was

on its own, by simple trial-and-error learning. To make that comparison, the model calculates a “social transmission effect,” which captures how much interacting with knowledgeable individuals accelerates the pace at which a whale picks up the lobtailing behavior, relative to trial-and-error learning. The social transmission effect was huge and the results striking: so striking that Rendell didn’t believe what he was seeing. “Luke basically was like, ‘Oh, 2024

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you’ve done something wrong,’” Allen says. “‘You have to go back [and reanalyze].’” Allen, Rendell, and Hoppitt did check after check of the code and the data, looking for some sort of error or artifact, but the results held up. Still, Allen and her colleagues wondered whether there was some other, possibly simpler alternative than cultural transmission that could explain why lobtailers in the foraging network were associating with one another. Allen knew that lobtail feeding most often occurs when whales are foraging on sand lance (Ammodytes americanus),

ine that whale 1 was spotted lobtail feeding on sand lance for the first time on December 31, 1999. Allen and her colleagues would know who whale 1 was swimming around with before that date. If they focused on that time period, they could test if whale 1 had been interacting with lobtailers before being a lobtailer itself. That meant they didn’t need to worry that, starting January 1, 2000, lobtailing whale 1 might be associating with other lobtailers because they all just cluster around sand lance. When they analyzed the data this way, they found that simply hanging around

Simply hanging around where the sand lance were did not explain why lobtail foraging had spread. Instead, the practice was spreading along the humpback whale network via cultural transmission. a fish found in the Gulf of Maine. Maybe the reason that lobtailers were found together was not that lobtailing behavior spread throughout their foraging network by cultural transmission, but because the lobtailers were all drawn to the sand lance populations. To test for this possibility, Allen and her colleagues discarded all associations after a whale had been seen lobtail foraging for the first time. So, for example, imag182

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where the sand lance were did not explain why lobtail foraging had spread as it had. As Allen had long thought was true but had no way of knowing for certain until they took social networks into account, information about lobtail feeding was spreading along the humpback whale foraging network via cultural transmission. Whether it’s macaques on Kǀjima Islet, bottlenose dolphins in Shark Bay, or

humpback whales in the Gulf of Maine, cultural transmission plays a role in the dynamics of social networks. The more we learn about social networks in nonhumans, the more we realize that those networks are remarkably complex. This recognition has led to new lines of collaborative research. Historically, fields such as animal behavior, disease ecology, and conservation biology have been distinct, and often disjointed, research enterprises. Social network analysis is an ideal bridge between them. Bibliography Allen, J., M. Weinrich, W. Hoppitt, and L. Rendell. 2013. Network-based diffusion analysis reveals cultural transmission of lobtail feeding in humpback whales. Science 340:485–488. Kawai, M. 1965. Newly-acquired pre-cultural behavior of the natural troop of Japanese monkeys on Koshima Islet. Primates 6:1–30. Kawamura, S. 1959. The process of subcultural propagation among Japanese macaques. Primates 2:43–60. Krützen, M., J. Mann, M. R. Heithaus, R. C. Connor, L. Bejder, and W. B. Sherwin. 2005. Cultural transmission of tool use in bottlenose dolphins. Proceedings of the National Academy of Sciences of the U.S.A. 102:8939–8943. Mann, J., M. A. Stanton, E. M. Patterson, E. J. Bienenstock, and L. O. Singh. 2012. Social networks reveal cultural behaviour in tool-using dolphins. Nature Communications 3:980. Lee Alan Dugatkin is a behavioral ecologist and historian of science in the biology department at the University of Louisville. This article is excerpted and adapted from The Well-Connected Animal: Social Networks and the Wondrous Complexity of Animal Societies, published by the University of Chicago Press, © 2024 by Lee Alan Dugatkin. Email: [email protected]

From Allen, 2013

In 1981, researchers in the Stellwagen Bank National Marine Sanctuary at the mouth of the Massachusetts Bay recorded the first sighting of lobtail feeding outside of the Gulf of Maine, where the practice had originated the previous year. The behavior quickly spread (a) and by 2007, 37 percent of the humpback whale population in the region had been informed of the practice (b).

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S c i e n t i s t s’

Nightstand

The Scientists’ Nightstand, American Scientist’s books section, offers reviews, review essays, brief excerpts, and more. For additional books coverage, please see our Science Culture blog channel online, which explores how science intersects with other areas of knowledge, entertainment, and society.

Earth 2.0 Could Be Just Around the Corner

ALSO IN THIS ISSUE

W

THE WALTZ OF REASON: The Entanglement of Mathematics and Philosophy. By Karl Sigmund. page 186

ONLINE On our Science Culture blog: www.americanscientist.org/blogs /science-culture American Eclipse Astrophysicist and eclipse expert Angela Speck reviews American Eclipse: A Nation’s Epic Race to Catch the Shadow of the Moon and Win the Glory of the World.

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Michael L. Wong ALIEN EARTHS: The New Science of Planet Hunting in the Cosmos. Lisa Kaltenegger. 288 pp. St. Martin’s Press, 2024. $30.00.

e stand at the doorstep of a scientific revolution: The discovery of extraterrestrial worlds that resemble our own could be just around the corner. For more than a decade, we have known that planets that are roughly the mass and radius of Earth orbit other stars. Without more detailed observations, however, these worlds are merely Earth-sized cue balls. Until now, astronomers have not possessed the capability to characterize exoplanets the size of Earth. But with the launch of the James Webb Space Telescope (JWST) in 2021, everything changed. The hunt is on. It’s fitting, then, that Alien Earths, Lisa Kaltenegger’s new book on the science of planet hunting in the cosmos, opens with a scene of her watching the launch of JWST. Like her, I was glued to the NASA TV livestream on my laptop that Christmas morning. Ten billion dollars of scientific equipment and an untold number of PhD theses were riding on a rocket that “carried the dreams,” Kaltenegger writes, “of thousands of scientists like me, hoping to catch a glimpse of the cosmos that had been beyond our reach—and our view—until now.” Alien Earths is, fundamentally, a book about hope. There’s no guarantee that astronomers will discover signs of life beyond Earth anytime soon, even with the fantastic capabili-

ties of JWST. But thanks to researchers like Kaltenegger, humanity is closer than ever before to answering the age-old question: Are we alone in the universe? Kaltenegger’s career—from her formative undergraduate years in Austria through her current position as the director of the Carl Sagan Institute at Cornell University—has been dedicated to putting humanity in the best possible position to identify signs of alien life. Kaltenegger is an astrobiologist: She studies life’s origins, distribution, and fate on Earth and in the larger universe. There is a double challenge in astrobiology: First, we must develop the capacity to detect the subtle imprints of alien biology; second, we must expand our understanding of life’s possibilities so we can recognize that a puzzling measurement indicates life rather than some bizarre geological process. Not one to recoil from a dare, Kaltenegger works on both sides: modeling different types of planets so we know where and how to look, and studying different types of life so we know what to look for. Throughout her book, Kaltenegger takes us on trips into her lab, where she grows microbes of every color in the rainbow to learn how to detect their chemical fingerprints with a telescope, and also into her computer terminal, where she whips up worlds populated by different combinations of life-forms via strings of code. Alien Earths explores not only what Kaltenegger does as a scientist, but also why. The anecdotes that Kaltenegger shares give readers a glimpse into what has informed her research interests and approach to her work. We get a sense of what her dreams are—the passion for her work that led her to cross oceans in pursuit of her career, seek out colleagues from a range of other fields, and establish the Carl Sagan Institute. She also recounts her personal journey in

Carsten Steger/Wikimedia Commons/CC BY-SA 4.0 DEED

Bacteria that prefer different temperatures tend to have different colors. Seeing this in action at Grand Prismatic Spring at Yellowstone National Park got Kaltenegger thinking: If there were a planet covered in microbes, the living conditions would affect their color. Looking for planets that have different colors, then, might be helpful in the search for alien life.

academia. Kaltenegger does not shy away from describing the challenges she’s faced throughout her career as an alien hunter—“They kept asking why I was working on something I might never find”—and as a woman in astronomy, a traditionally maledominated discipline. In one memorable passage, Kaltenegger describes how, as a postdoc in 2008, she discovered her scientific niche while on a trip to Yellowstone National Park. Mesmerized by the www.americanscientist.org

biological hues of the Yellowstone hot springs, Kaltenegger realized her calling: Watching these colorful organisms made me notice how broad the range of colors of life are. Just imagine a planet with hot sulfur springs covering its surface, where life creates a rainbowcolored world. I realized that astronomers needed a color catalog of life—a database of diverse

Earth biota and information on how they reflected incoming starlight—to compare to what our telescope would find on exoplanets. If we didn’t want to miss out on finding life in the universe, scientists needed a comparison chart that included more than just green plants. While observing a geological wonder, Kaltenegger had identified a missing piece of the astrobiological puzzle: a chromatic archive of life’s diverse pigments against which to compare astronomical observations. In other words, looking for life requires knowing about the different ways that life can look. 2024

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This realization sparked her to fill that gap through an innovative blend of biology and astronomy: by growing microbial life in the lab and simulating how such life on an alien world might appear through a telescope. Beyond Kaltenegger ’s personal contributions to the field, Alien Earths is also an expansive introduction to the multidisciplinary field of astrobiology. Though you’ll find deeper explanations of certain scientific topics in other, more focused texts, Kaltenegger successfully connects ideas from disparate fields—from prebiotic

other stars—big and small, near and far, scorching hot and just the right temperature (perhaps) for life. Here, we get a sense of how exoplanetary science is swirling toward the detection of possibly habitable worlds. Kaltenegger leads with the discoveries of hot Jupiters, the first kind of exoplanets to be found orbiting Sunlike stars. Although these gargantuan puffballs are far too toasty to sustain life as we know it, they nonetheless demanded significant revision to our conception of planet formation. She then describes how NASA’s Kepler

In other words, looking for life requires knowing about the different ways that life can look. chemistry to geology to astronomy— to reveal a big-picture understanding of the possibilities for life in the universe. Her lyrical prose weaves the wonder of discovery, the thrill of cutting-edge research, and the splendor of the cosmos into an accessible and inspiring read. Particularly impressive are her clever analogies that make the impossibly large (in size) or long (in time) more reader friendly. For example, Kaltenegger translates how fast our Sun is losing mass (five million tons per second) into a more visual unit: 50,000 adult blue whales per second. In another instance, explaining how the ocean tides created by the gravity of both the Moon and the Sun are slowing Earth’s rotation by roughly two milliseconds each century, she quips: “That means that in about two hundred million years, I will finally get that extra hour of the day I’ve always hoped for.” Who among us can’t relate to that yearning for an additional hour of time? The book packages a vast array of research into an elegantly written, logically laid-out story. The first half of Alien Earths surveys the principles of planetary habitability, theories about life’s origins, and techniques that scientists use to look for life beyond Earth. In the second half, Kaltenegger plays exoplanet tour guide, showing off the amazing worlds that astronomers have found orbiting 186

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space telescope, launched in 2009, brought us down in scale to superEarths, between the size of Earth and Neptune; the detection of such worlds revolutionized our understanding of planetary diversity, because our solar system lacks anything comparable. Though we owe thousands of exoplanet discoveries to Kepler, this spacecraft failed to find true Earth analogs that could be readily interrogated for chemical signs of life. Motivated to discover the nearby exoplanets that would be most amenable to searching for alien biospheres, Kaltenegger played a leading role in making NASA’s Transiting Exoplanet Survey Satellite (TESS) mission possible. When the time finally came for the launch of TESS in 2017, she brought her family to Cape Canaveral to witness the event. She was not only able to share the wonder of that rocket launch with her four-year-old daughter, but also the wonder of thousands of additional exoplanet discoveries with like-minded individuals. Alien Earths conveys how difficult the search for life in the universe is—and the incredible advances that have finally put scientists in a position to try to answer that age-old question. Although Kaltenegger never quite gives an answer to what that life might look like (the universe is bound to surprise us), she provides an extraordinary tour of how science has

developed the tools that will bring us closer to finding and recognizing alien life. In other words, it’s more about the journey than the destination. With the launch of spaceborne observatories like Kepler, TESS, and JWST, we are living through an exoplanetary revolution: one led, in no small part, by Kaltenegger herself. Throughout the book, she maintains a sense of optimism, writing, “Among the thousands of exoplanets we have discovered, perhaps we have already found the first that could be an alien Earth. With two hundred billion stars in our galaxy alone, the odds of finding life seem to be ever in our favor.” Alien Earths reminds us that although there have been many triumphs in exoplanetary science to date, the biggest discovery of all still lies in wait. Michael L. Wong is a NASA Sagan Postdoctoral Fellow at the Carnegie Institution for Science’s Earth & Planets Laboratory. An astrobiologist and planetary scientist, he studies the emergence of life, planetary habitability, and how to look for signs of life beyond Earth. In his spare time, he hosts Strange New Worlds: A Science & Star Trek Podcast.

Do You Wanna Dance? Daniel S. Silver T H E WA LT Z O F R E A S O N : T h e Entanglement of Mathematics and Philosophy. Karl Sigmund. 448 pp. Basic Books, 2023. $32.50.

A

re mathematics and philosophy entangled? The question would have seemed senseless to Plato. In ancient Greece, mathematics served philosophy. Since the days of ancient Athens, philosophy and mathematics have grown into separate, ever-expanding fields. Today, the question of how mathematicians and philosophers interact with one another is a reasonable one. The Waltz of Reason gives us clues to some possible answers by introducing us to some of the dance partners in the history of mathematics. Karl Sigmund, a professor emeritus of mathematics at the University of Vienna, writes clearly and with subtle wit, making The Waltz of Reason highly readable, with plenty of illustrations.

In his Commentaries, Julius Caesar divided all of Gaul into three parts. In his book, Sigmund outlines four parts to separate the vast realm of mathematics. The first part encompasses geometry, numbers, infinity, logic, and computation—a staggering amount of material. Part two addresses limits, probability, and randomness. The author ’s research interests are reflected in the third part, covering voting, game theory, and fairness. The final part includes topics of language, philosophy, and understanding. Sigmund is aware of the large volume of material that he covers in the book: In his introduction, he confesses to feeling like the aging fisherman in Ernest Hemingway’s The Old Man and the Sea, who caught more than he could manage. Despite the overfishing, The Waltz of Reason is a relaxed and refreshingly direct account. Consider this lead-in to a discussion of chance:

Throughout the book, Sigmund explores how mathematicians and philosophers have influenced one another. For example, when considering Aristotle and the 19th-century English mathematician George Boole, Sigmund writes, “The most remarkable insight of Aristotle was to describe logical arguments by a formal calculus: the content of the proposition was irrelevant. Admittedly, he used no mathematical formulas, yet his rules begged to be formalized.” Boole, the son of a cobbler and mostly self-educated, gave us such a formalization. He began by recognizing that the logical connectives and and or can be modeled by multiplication and addition. Another hundred years after that, algebraic language developed from Boole’s ideas would help to make digital computers possible. Since then, computers have transformed the world, mostly for www.americanscientist.org

Kurt GÖdel/Wikimedia Commons/CC BY-SA 4.0 DEED

Chance is notoriously hard to define. Is it the force that causes something to happen without reason for doing so? Something that happens when several causes intermingle? Something that can be, but also not be? This is just a small sample (a random sample) of attempts to explain the word chance. Mathematicians, however, do not try to define chance. They want to reckon with it.

Kurt Gödel is thought to be one of the most important logicians in history. He not only contributed to mathematics, but also influenced thinkers in science and philosophy. In 1987, the Kurt Gödel Society was established to promote research in logic, philosophy, and the history of mathematics.

the better. (Safer to say that. After all, ChatGPT might be reading this.) The Waltz of Reason proposes other examples of mathematicians whose views were influenced by philosophy. Among them are two brilliant 20thcentury mathematicians, Kurt Gödel and Alan Turing. What logician can compare to Aristotle? According to Albert Einstein, it was Kurt Gödel. As a child, Gödel was called “Mr. Why” by his family because of his constant demand for reasons. During his studies at the University of Vienna in the 1920s, he was invited to join a private group

of distinguished mathematicians and philosophers, known later to the public as the Vienna Circle. Sigmund writes, “For philosophy of mathematics, this was the best of times. Three great schools, headed by formidable thinkers, were contending with each other—and most remarkably, many mathematicians actually cared!” The three schools to which Sigmund is referring represented versions of a philosophical movement called logical positivism. Their respective positions can be capsulized as follows: Mathematics is formal logic; mathematics is merely symbol 2024

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manipulation; and mathematics is only a mental construction. Gödel remained mostly quiet during the group’s many debates. He was no logical positivist—far from it! Rather, Gödel shared Plato’s vision of mathematics as independent of us: something to be discovered, not invented. Such thoughts were considered primitive—even anathema—to logical positivists. During one gathering of the Vienna Circle, Gödel announced the first of his two “incompleteness theorems.” Given any consistent set of arithmetical axioms, Gödel showed that there are true statements that cannot be proven from the set. One might prove them by adding additional axioms (provided the system remains consistent) but then other unprovable true statements will appear. Only one other attendee, Gödel’s former teacher Moritz Schlick, paid much attention. The belief that the Vienna Circle’s phi-

rival was as momentous for humanity as that of agriculture or writing.” Turing was not a philosopher, although he is sometimes called that. One reason philosophers claim him is that he contemplated the question of whether a computer might someday be able to think, though he pronounced the question “too meaningless to deserve discussion.” Intelligence, Turing believed, is an emotional concept, not a mathematical one. In response to the question, he presented what he called “the imitation game.” The game, now called the Turing test, asks a human at a remote device to communicate with a human and a computer, and then try to decide which is which. Turing’s ideas about computers’ capacity for thought will likely be revisited in the future, as “digital assistants” answer our telephone calls and artificial intelligence is used to replace humans in the workforce.

Gödel shared Plato’s vision of mathematics as independent of us: something to be discovered, not invented. losophy influenced Gödel’s discovery is widespread. It is also wrong. In effect, Gödel was telling us that truth is not the same as provability. Eventually, this notion would pique the interest of many other philosophers, with countless books and articles published on variations of this theme. Cambridge-educated mathematician Alan Turing, born in London in 1912, expanded on Gödel’s incompleteness theorems. Turing showed that a mechanical process that could test the truth of certain mathematical yes-or-no questions is impossible. In order to do this, Turing created an imaginary “computing machine,” one that manipulated strings of symbols on a strip of tape, following a table of rules. The significance of Turing’s thought experiment cannot be overstated. Sigmund writes that Turing’s machines “yielded the blueprint for the stored-program computer. Its ar188

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The real motivation for Gödel and Turing did not come from philosophers. It came instead from challenges posed by David Hilbert, possibly the most influential mathematician of the late 19th and early 20th centuries. Specifically, it was Hilbert’s program, which proposed a formalization of all mathematics, that spurred both Gödel and Turing. Philosophers were given much to think about by Gödel and Turing. But did philosophy contribute anything helpful to them, or to other mathematicians for that matter? The Waltz of Reason lacks a satisfactory answer. What the book does reveal is the zeitgeist, the spirit of the times, to which philosophy contributes. Mathematicians, like artists and musicians, absorb that spirit, at times enabling it to emerge through their work. Although Turing created a purely theoretical machine that so produc-

tively manipulated symbols, it was the Hungarian American mathematician John von Neumann who introduced a physical design in the 1940s that would be a model for future digital computers, paving the way for the modern computer. Von Neumann appears again in a later chapter, where we read about game theory. Game theory is applied mathematics, that is, mathematics applied to other fields. Game theory models situations in which “players” make interdependent decisions for gain or loss. The players might be having a harmless game of cards or they might be contemplating nuclear war. In 1943, von Neumann and the economist Oskar Morgenstern published Theory of Games and Economic Behavior, a comprehensive introduction to game theory. The book attracted widespread attention and glowing reviews, but game theory was slow to catch on in the social sciences, partly because of its mathematical demands. Today it is a standard tool in behavioral economics, and of great interest in ethics. The Waltz of Reason contains an excellent introduction to game theory. We learn how game theorists drew motivation from other fields—in this case, ethics, psychology, and sociology. Of course, that is what applied mathematicians are supposed to do. Pure mathematicians, on the other hand, must restrict their claims to statements that they can verify with certainty. Philosophical speculations inserted into mathematical journal submissions are unlikely to get past referees and editors. But that doesn’t mean that some mathematicians don’t discuss together occasional philosophical questions that appear to be related to their work. They do. Certainly, mathematics and philosophy are in a relationship, but precisely what philosophy contributes to that relationship is a difficult question. Although Sigmund does not give a complete answer, the book does provide an entertaining look at how, during the past few centuries, philosophy and mathematics have at least watched each other from across the ballroom floor. If just for that, The Waltz of Reason is well worth a dance. Daniel S. Silver is an emeritus professor of mathematics at the University of South Alabama. His research is in topology. He also writes on the history of science and the psychology of invention.

Volume 33 Number 03

May–June 2024

Sigma Xi Today A NEWSLETTER OF SIGMA XI, THE SCIENTIFIC RESEARCH HONOR SOCIETY

Call for Leadership Nominations Sigma Xi is seeking nominations for qualified candidates to fill positions for the Board of Directors, Associate Directors, and Committee on Nominations for representation of regions and constituencies. The following positions carry three-year terms: Board of Directors: Area Groups, Industries, State & Federal Labs Constituency Comprehensive Colleges & Universities Constituency North Central Region Southwest Region Associate Directors: Canadian/International Constituency Baccalaureate Colleges Constituency Mid-Atlantic Region Northeast Region Committee on Nominations: Membership-at-Large Constituency Research and Doctoral Universities Constituency Northwest Region Southeast Region Nominations should be submitted to [email protected] by June 30, 2024. Active full members of Sigma Xi are eligible to run for office. An inactive member may become active at any time through payment of current dues. Sigma Xi seeks diverse and inclusive slates for all its elected positions. Self-nominations are welcomed. Visit sigmaxi.org/elections24 to view a list of duties, responsibilities, and full qualification criteria for each position.

Sigma Xi Today is managed by Jason Papagan and designed by Chao Hui Tu.

www.americanscientist.org

From the President Passing the Torch Over the past few years, one can scarcely open a prestigious national magazine or newsletter without coming across a sordid story about plagiarism at the highest echelons of science. There have been incidents at some of our most renowned institutions: Stanford, Massachusetts Institute of Technology, Caltech, Harvard, and others. It’s both hard to wrap your mind around and very discouraging—and you’d be forgiven for wondering if there truly is an irresistible temptation for competitive scientists to take shortcuts. Adding to this is the fact that the publication of scientific literature has become big business. The number of new publications in traditional and interdisciplinary fields has been increasing steadily. Even before we had the help of computers and powerful algorithms, a few skilled individuals seemed able to predict the next steps in research with reasonable confidence. And they were often right, though not always. But today’s highly competitive landscape has culminated in the creation of a new kind of scientist: the accomplished technician who seemingly publishes a new paper every 37 hours. Such successes—or maybe we should call them abscesses—indicate not so much that certain individuals have mastered the publish-or-perish game, but rather that the standard that society has set for scientists is no longer tenable. Clearly, we must reassess the core values of scientific research. In my opinion, the work of the true research scientist must include enhancing the health of the overall research enterprise, fostering integrity in science, and promoting the public’s understanding of science for the purpose of improving the human condition. Put more simply, all scientists should practice and promote ethics and excellence at all times in their research. The true scientist is also dedicated to mentorship and to the advancement of knowledge through research, service, and teaching. And then, of course, there is the work itself: The true scientist must painstakingly check and recheck their results, methodologies, and assumptions. Only in that way, in community with equal-minded peers, can we build the scientific advances and engineering bases of our increasingly technological society. This, I submit, is the profile of a Sigma Xi member. With this letter, I prepare to conclude my one-year tenure as president of Sigma Xi. I am very proud to report that we’ve seen our first increase in membership in the past 10 years, along with our largest ever in-person annual meeting attendance at the 2023 IFoRE conference. I thank the Sigma Xi staff and our amazing membership, who were all instrumental in achieving these accomplishments during my presidency. In July 2024, I will transfer leadership to our current president-elect, Kathy Lu. She will chart the future course of Sigma Xi and its continued prosperity.

Marija Strojnik 2024 May–June 189

Award-Winning Speakers Distinguished thought leaders are a cornerstone of the IFoRE agenda. Keynote and general sessions will provide attendees with the opportunity to take part in lively discussions, interviews, career workshops, and presentations of cutting-edge research.

Student Research Competition One of the flagship components of the IFoRE conference is the presentation of research from high school, college, and graduate students from across the globe. Participating STEM students will share their research with professional judges via oral or poster presentation.

International Forum on Research Excellence November 14–17, 2024 | The Capital Hilton Hotel | Washington, D.C. Sigma Xi’s annual conference, the International Forum on Research Excellence (IFoRE) will return to the East Coast in 2024. The four-day event will take place November 14–17, 2024, at The Capital Hilton Hotel in Washington, D.C. Now in its third year, IFoRE represents an immersive demonstration and celebration of excellence in research across all STEM disciplines. The conference is open to all researchers and supporters of science worldwide, including Sigma Xi members, students, educators, policymakers, and science communicators.

Visit experienceIFoRE.org to register.

Networking Events Get your groove on and unwind at IFoRE’s unique networking events.

Awards Banquets IFoRE attendees will be treated to special speakers, programming, and award ceremonies, while they meet, greet, and eat at the conference banquet events. 190

Sigma Xi Today

GRANTS IN AID OF RESEARCH

of GIAR : Anne Elizabeth Thaxton Grant: $1,000 in Spring 2022 Education level at time of the grant: Undergraduate student Project Description: We used three scorpion species, Diplocentrus lindo, Vaejovis intermedius, and Centruroides vittatus, to observe if there is niche partitioning among the species through observation of differing gene transcription. To study this, we collected venom glands from each species and extracted the mRNA from the samples. We then prepared cDNA libraries to test for differential expression. We found differences in gene expression, likely leading to the translation of different proteins in the venom of each species. This may limit competition against one another for the same resources within their environment. Our study is the first to generate transcriptomes for two of these species, and it increases our understanding of interspecific venom variation.

How did the grant process or the project itself influence you as a scientist/researcher? The grant application process gave me confidence as a researcher. As an undergraduate student, it can be very intimidating to initiate and present a research project. Applying for the GIAR award allowed me to distill and clarify my project goals, and it helped me refine my skills in sharing the research I had embarked upon. What advice would you give to future applicants? I would advise future applicants to apply, even if you do not feel as though you are ready to take on the challenge. Regardless of the outcome, you will grow in your own understanding of your project as you condense your knowledge, data, and goals into a cohesive proposal. Where are you now? After defending my honors thesis in April 2024, I will graduate in May with a bachelor’s degree in biology and a minor in related sciences. I will then attend the Frederick P. Whiddon College of Medicine starting in July 2024.

of GIAR : Jyoti R. Behera Grant: $1,000 in Fall 2023 Education level at time of the grant: PhD student Project Description: My primary objective in the proposed research was to gain insights into the metabolism of healthy oils within the avocado mesocarp, spotlighting the novel transcription factor WRINKLED2 (WRI2), which plays a pivotal role in the regulation of fatty acid synthesis. I employed qRT-PCR and yeast one-hybrid assay techniques to pinpoint the target genes of WRI2 in avocado mesocarp tissue. The results revealed a similar promoter recognition sequence of WRI2, positioning avocado WRI2 as a viable alternative to native WRIs, which presents an opportunity to enhance the production of health-enhancing vegetable oils in diverse plant species.

How did the grant process or the project itself influence you as a scientist/researcher? Writing the grant proposal helped me learn how to express my ideas in a clear and simple way. Thinking about different topics for the grant sparked many more ideas for my research. As a result, my advisor and I wrote another grant proposal for potential federal funding. What advice would you give to future applicants? Keep it concise and accessible to a broad audience. Aim for clarity and motivation in the first few sentences to engage the reviewer. Avoid excessive technical details, but provide enough depth that goes beyond superficial explanations.

Students may apply for Sigma Xi research grants by March 15 and October 1 annually at sigmaxi.org/giar.

www.americanscientist.org

2024 May–June 191

CHAPTERS & MEMBERS

2024 Distinguished Lecturers Since 1937, Sigma Xi has presented its Distinguished Lecturers. This program is an opportunity for chapters to host visits from outstanding individuals who are at the leading edge of science. Lecturers communicate their insights and excitement to a broad range of scholars and to the community at large. Each year, thousands of Sigma Xi members, students, and the public have an opportunity to hear exceptional talks and to ask questions of experts. The Lectureship Program is supported by Sigma Xi members with additional support from partnering organizations such as the American Meteorological Society, the National Academy of Engineering, and the National Cancer Institute. To learn more about specific speakers and lecture topics, visit sigmaxi.org/lectureships. To schedule a speaker or sponsor a lecture, email [email protected]. Charles I. Abramson Oklahoma State University

Supriyo Bandyopadhyay Virginia Commonwealth University

David B. Allison

Steven Austad

David A. Bader

Indiana University Bloomington, School of Public Health

University of Alabama at Birmingham

New Jersey Institute of Technology

Brad Barlow

Marcia Bartusiak

High Point University

Massachusetts Institute of Technology

Nikhilesh Chawla

Mukund Chorghade

Purdue University

THINQ Pharma

Joseph J. Biernacki Tennessee Technological University

Lynn Cominsky

Peer Fischer

Sonoma State University

University of Stuttgart

James Hamilton

Reyco Henning

Bradley Hoggatt

John R. Jungck

University of Wisconsin– Platteville

University of North Carolina at Chapel Hill and Triangle Universities Nuclear Laboratory

MSI GuaranteedWeather

Delaware Biotechnology Institute

Haagen Klaus George Mason University

Steven Richardson

Akhlesh Lakhtakia The Pennsylvania State University

Dante Lauretta

June Pilcher

University of Arizona

Clemson University

Anne Savage

Karen C. Seto

Michael Shur

Proyecto Titi, Inc.

Yale University

Rensselaer Polytechnic Institute

Howard University

Ramteen Sioshansi Carnegie Mellon University

John R. Speakman

Fred H. Smith Illinois State University

Karen B. Strier University of Wisconsin– Madison

University of Aberdeen

Jeffrey Toney

George Veni

Jut Wynne

Enrico Zio

Kean University

National Cave and Karst Research

Northern Arizona University

MINES ParisTech, PSL Research University

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INTERNATIONAL FORUM ON RESEARCH EXCELLENCE November 14–17, 2024 | Washington, DC

REGISTER AT experienceIFoRE.org

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