Volume 109. Number 1. January–February 2021 
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Life lessons from PLANTS AS WITNESSES

New theories zero in on ALZHEIMER'S CAUSES



Scientist January-February 2021


Could Earth's long-neglected neighbor help us find other habitable worlds?


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Scientist Departments

Volume 109 • Number 1 • January–February 2021

Feature Articles 38 Plants as Teachers and Witnesses One plant biologist reflects on seasonal re-pacing in a culture of constant action, as a gift learned from her study subjects. Beronda L. Montgomery

2 From the Editors 3 Letters to the Editors 6 Spotlight Ancient fire scars of the Petrified Forest • Glacial gumshoe • Fire management in an age of contagion • Briefings

46 Dangers of Divided Attention Multitasking may seem to be a timesaver, but the working memory can only handle one task at a time, so attempts to divide concentration inevitably backfire. Stefan Van der Stigchel

16 Sightings Subtle as a flying hammer 18 Perspective Could infections make us vulnerable to Alzheimer’s disease? Islam Hussein 22 Engineering A bicentennial in a pandemic Henry Petroski 26 Technologue The dark past of algorithms that associate appearance and criminality Catherine Stinson

Scientists’ Nightstand 54 Book Reviews Using data to end oppression • Combating specious ideas

30 30 Unveiling Earth’s Wayward Twin Venus, the closest planet, seems like a hellish version of our own; studying how it got that way will tell us a lot about the prospects for life among the stars. Paul K. Byrne



What are you working on? How is your work project going?

When will you be finished?

From Sigma Xi 60 Distinguished Lecturers, 2021–2022 62 Sigma Xi Today A historic occasion • Grants in Aid of Research recipient profile • Annual Meeting and Student Research Conference discussed science–art collaborations

Social Media • email • twitter

The Cov er Maat Mons, an enormous shield volcano on Venus, is a prime example of the planet’s familiar yet utterly alien landscape, as Paul K. Byrne describes in “Unveiling Earth’s Wayward Twin” (pages 30–37). The volcano’s overall structure is reminiscent of the ones that make up the Hawaiian islands, but the planet’s high surface temperature—above 450 degrees Celsius—and lack of water resulted in extensive, distinctive lava flows. The image itself is also unusual. Because of the perpetual cloud cover on Venus, planetary scientists have to use radar to map its surface. This radar snapshot, acquired by NASA’s Magellan orbiter in 1989, is colorized to resemble surface views from the Soviet Venera landers and is vertically exaggerated to highlight the landforms. In reality, Maat Mons stands 5 kilometers above the surrounding plains; circumstantial evidence suggests it might still be erupting. Going back for better data on Venus, says Byrne, might help us understand how it got this way and why Earth didn’t, and it could help us better characterize exoplanets. (Image by NASA/JPL)

From the Editors AMERICAN

The Pace of Life

Scientist www.americanscientist.org


s the Northern Hemisphere heads into winter and cases of COVID-19 have been on the rise, we hope that you are doing everything you can to keep yourselves safe during these difficult times. As always, feel free to reach out to us on social media or by email to let us know how the pandemic is affecting your research, your university, or other aspects of your life. In a recent reader survey, some of you indicated that you’d like more special content on coronavirus, so we wanted to point you to some resources. We’ve made a point to include content about SARS-CoV-2 in every issue since the pandemic began, with additional information in online blogs. We recently put together a special collection of articles titled Pathogens and Pandemics, which is available online to Sigma Xi members and American Scientist subscribers. That collection includes a list of links to all our coronavirus coverage. A new addition to this online coverage is a video of a virtual talk by virologist Efraín Rivera-Serrano, a science communicator who collaborates with American Scientist and other venues. Rivera-Serrano discusses microscopy experiments that show how viruses find target cells and how cells fight back, revealing targets for antiviral treatments. (You can see highlights of this talk and many others, including all the recent Sigma Xi Virtual COVID-19 Distinguished Lectureship series, on our Twitter feed.) In this issue, you’ll also find the first Q&A based on our collaboration with the podcast COVIDCalls; this interview discusses how the response to this pandemic provides a new framework through which to approach wildfire management (pages 11–13). Have you been working from home during this pandemic? If so, you might be finding yourself pulled in competing directions between projects, domestic duties, perhaps family caretaking, and other distractions. Stefan Van der Stigchel takes on the myth of multitasking, and provides some tips for more efficient concentration and time usage, in “Dangers of Divided Attention” (pages 46–53). All the changes to your work and social life might be inspiring you to step back and reexamine your habits and patterns. In “Plants as Teachers and Witnesses” (pages 38–45), plant biologist Beronda L. Montgomery discusses how she has taken cues from the seasonal re-pacings of plants to guide her own life patterns. If the many upheavals of the world have been causing you to engage more with the daily news, you have likely heard about recent results indicating that Venus’s atmosphere contains molecules that, on Earth, are currently known to have mostly an organic origin. In “Unveiling Earth’s Wayward Twin” (pages 30– 37), Paul K. Byrne takes a critical look at those results, and many other aspects of our long-neglected neighbor planet. Venus may have been a lot like Earth at one point, but it diverged somewhere along its developmental path. Understanding Venus could not only tell us more about its mysteries, but also help us tease out properties of exoplanets, including whether they could be habitable. Although we’re currently living with the immediate stresses of a pandemic, it’s important not to lose sight of the bigger environmental issues that face Earth, and Venus could provide some clues. —Fenella Saunders (@FenellaSaunders)

VOLUME 109, NUMBER 1 Editor-in-Chief Fenella Saunders Managing Editor Stacey Lutkoski Senior Consulting Editor Corey S. Powell Digital Features Editor Katie L. Burke Senior Contributing Editor Sarah Webb Contributing Editors Sandra J. Ackerman, Emily Buehler, Christa Evans, Jeremy Hawkins, Laura Poole, Diana Robinson Editorial Associate Mia Evans Intern Reporter Madeleine Feola Art Director Barbara J. Aulicino SCIENTISTS’ NIGHTSTAND Book Review Editor Flora Taylor AMERICAN SCIENTIST ONLINE Digital Managing Editor Robert Frederick Acting Digital Media Specialist Kindra Thomas Acting Social Media Specialist Efraín E. Rivera-Serrano Publisher Jamie L. Vernon CIRCULATION AND MARKETING NPS Media Group • Beth Ulman, account director ADVERTISING SALES [email protected] • 800-282-0444 EDITORIAL AND SUBSCRIPTION CORRESPONDENCE American Scientist P.O. Box 13975 Research Triangle Park, NC 27709 919-549-0097 • 919-549-0090 fax [email protected][email protected] PUBLISHED BY SIGMA XI, THE SCIENTIFIC RESEARCH HONOR SOCIETY President Sonya T. Smith Treasurer David Baker President-Elect Robert T. Pennock Immediate Past President Geraldine L. Richmond Executive Director Jamie L. Vernon American Scientist gratefully acknowledges support for “Engineering” 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 USA


American Scientist, Volume 109

Letters Thermal Terms To the Editors: “Hummingbird and Bat Pollinators of the Chiricahuas” by Theodore H. Fleming, M. Brock Fenton, and Sherri L. Fenton (November–December 2020) is an informative and detailed article about the interactions between flora and fauna in a lovely area of the desert southwest. I was, however, disappointed to see the authors use the terms warm-blooded and cold-blooded in describing birds, bats, and insects, particularly when this statement was used as a highlighted piece of text. Those terms are confusing at best and at worst incorrect. They imply that all birds and mammals regulate and maintain high body temperature at all times, while insects do not regulate at all. The correct terms would be endothermic and ectothermic, but even those terms do not always apply to all animals in a group. For example, there are many species of endothermic insects, such as moths and bees that pollinate arctic flowers. Many bats and hummingbirds are heterotherms that employ the strategy of daily torpor, allowing body temperature and metabolic rate to drop at night to conserve energy.

I am often told that the general public would not understand the scientific terms, and thus it is necessary to use simplified terminology. American Scientist, however, includes many scientists among its readers. I think my fellow readers, even if they are not thermal biologists, can understand a few scientific terms for the purpose of avoiding confusion and accidental misinformation. Polly K. Phillips Miramar, FL

Structural Integrity To the Editors: Henry Petroski’s Engineering column in the November–December 2020 issue, “Towers: Upright, Leaning, and Collapsed,” got my attention. I was interested not only because of the descriptions of structural integrity degradation over long time periods but also because I live near a 20-meter leaning brick chimney. It was originally part of the heating system for a greenhouse that was crushed in a heavy snowfall a few years ago. The greenhouse lot is now used for boat and RV storage, but the chimney remains. The chimney stands alone about 20 meters east of a street that I travel nearly every day. It has a slight lean to the

south that I measured to be 1.90 degrees. The appearance of the lean, however, is markedly affected by the direction I am traveling: When I’m driving north it appears to be perfectly vertical, but when I’m going south the lean gives the impression that it might fall over at any time! A somewhat unusual road layout with various curves and changes in slope is evidently the reason for this Escheresque visual trickery. The mental processes going on in these sorts of situations is something I had not thought about until I read the Engineering column and decided to quantify the chimney effect. Thanks for taking this physicist out of his swim lane! Paul Temple Post Falls, ID

Problematic Solutions To the Editors: I love American Scientist and read most issues cover to cover. The consistent emphasis on connecting disciplines and highlighting complexity are key strengths. What has compelled me to write, however, is that in articles that so clearly recognize complexity, authors

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: add $8 for shipping; other foreign subscriptions: add $16 for shipping. U.S. institutional rate: $75; Canadian $83; other foreign $91. Copyright © 2021 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. Second-class postage paid at Durham, NC, and additional mailing offices. Postmaster: Send change of address form 3579 to Sigma Xi, P.O. Box 13975, Research Triangle Park, NC 27709. Canadian publications mail agreement no. 40040263. Return undeliverable Canadian addresses to P. O. Box 503, RPO West Beaver Creek, Richmond Hill, Ontario L4B 4R6.

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Politics of Science

mechanisms to target for antiviral treatments. https://bit.ly/34OD7In Executive Order Hinders Scientific Inquiry

Andrey Atuchin

A ban on diversity and inclusion training for government employees and contractors may have farreaching effects. https://bit.ly/34QC6zN More Testing, Faster Testing The Crazy Anatomy of Horned Dinosaurs

What was the purpose of the big, bony frills on horned dinosaurs? Were they just for protection, or for mating, or were they also used in thermoregulation? In this podcast, Eric K. Lund, the paleontology conservation lab manager at the North Carolina Museum of Natural Sciences, discusses the latest research updates about ceratopsian, or horned, dinosaurs, showcasing their remarkable diversity and evolutionary history. https://bit.ly/3pE4tcI

More types of tests for the coronavirus are becoming available, but how do we know which to use when? https://bit.ly/2Jwa6Ju Answering Preschoolers’ Favorite Question: “Why?”

A curious bunny in the new PBS Kids cartoon Elinor Wonders Why uses scientific observations to learn about the world around her. https://bit.ly/3pJn3A6 Check out AmSci Blogs http://www.amsci.org/blog/

Image courtesy of Efraín Rivera-Serrano

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Join us on LinkedIn linkedin.com/company /american-scientist

Illuminating the Micro-World to Understand Viral Infections

Microscopy experiments demonstrate how a virus finds a target cell and how cells respond to stop the virus, revealing often discuss “solutions” to complex problems. A “solution” implies certainty and a sense of finality. When these “solutions” prove temporary or raise new problems, those who don’t appreciate complexity have cause to doubt the scientists who offered the perceived “solutions.” Further, the idea of “solving” is counter to being 4

American Scientist, Volume 109

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adaptable. Pressing social issues ranging from procuring energy and water to addressing poverty will never be “solved,” and using that language offsets the power found in recognizing their complexity. Kristan Cockerill Boone, NC

To the Editors: Fenella Saunders discussed the results of American Scientist‘s recent reader survey in the November–December 2020 “From the Editors” letter. She said, “About a third of survey respondents opted to leave a comment, and of those, about 15 percent (or about 5 percent of the total respondents) were requests that the magazine not discuss anything ‘political.’” For those scientists who wish to run away from “things political,” please keep in mind that those “things political” will find you, no matter how hard you try to avoid them. Those “things political” include politicians and their policies that are ascientific or antiscientific (of which there are many in current times). These politicians are the ones who can try to—and may successfully—take away the federal funding that makes your research possible, federal allowances for universities and other organizations to charge overhead that enables the universities to support the infrastructure through which scientific labs operate, federal funding that makes it possible for scientists to have graduate students and postdoctoral researchers, and respect for, and trust in, your work that most people used to have. These “things political” are not some future nightmare; they already are happening. So, if you are okay with a future that includes no funding, no infrastructure for labs, no advanced students, and no respect for or trust in your work, by all means run away from politics, realizing that you are compromising not only your own future but also that of future generations of scientists. Robert J. Sternberg Ithaca, NY

Cover Representation To the Editors: I am writing to raise concerns about the editors’ decision not to use the collective portrait of women scientists from my article, “The Women Who Discovered RNA Splicing” for the cover of the September–October 2020 issue. This collective portrait is a powerful visual that captures key aspects of my article. It conveys the women’s substantial presence (half a dozen) in a major scientific discovery. Most readers, who

Stephanie Freese

not using images of any actual people on covers, to keep the focus on concepts and to avoid portraying science as anything other than a collective endeavor built by many people. The choice of cover does not indicate any judgment on the worth of an article. The many forces of bias at play in the misallocation of this scientific credit were difficult to conceptually represent on the cover, but that makes them no less important among the topics we covered in this issue. Acknowledging underrepresented groups in science and increasing their representation are very important to American Scientist, and we continue to look for creative, evocative ways to do so. Dr. Abir-Am’s article has been featured in our electronic newsletter and on our social media feeds, receiving a highly positive response from readers. The researchers portrayed in this collective portrait from “The Women Who Discovered RNA Splicing” (September–October 2020) are (clockwise from top left) Sara Lavi, Louise Chow, Sayeeda Zain, Claire Moore, Susan Berget, and Mia Horowitz.

may have never encountered so many women scientist coauthors in a major discovery, would have been curious to learn more about their contributions, especially since the Nobel Prize for this discovery was given to two men. The portrait also counteracts ethnic bias in general and its intersectionality with gender bias in particular. Of the women scientists involved in the discovery of RNA splicing, four came from Asia (China, India, and Israel) and two from the United States. This cultural and regional diversity resonates well with the readers’ increasing interest in ethnic diversity while also providing young girls with muchneeded, multinational role models. The article’s key message on the corrosive impact of gender bias and injustice on the integrity of science would have been more memorable if transmitted by a cover projecting the diverse faces of the article’s protagonists—women scientists personifying a long-lasting injustice. I recognize that there are various constraints—technical, artistic, commercial, and others—that prevail in the process of determining the cover choice. In the aftermath of a prolonged public debate on the persistent underrepresentation of women in science, however, none of these plausible constraints justify displacing the evocative portrait of several women scientists whose story reveals key issues about bias, justice, and integrity in scientific discovery. www.americanscientist.org

A tradition of avoiding any portraits on the cover was mentioned as a reason for this decision. But such a tradition reflects a double standard: Men don’t need to be on the cover to signal their role in major discoveries, because such a role is culturally assumed and touted even when, as my article suggests, their sole role was anything but self-evident. By contrast, persisting gender bias has long prevented women from being recognized for their key roles in various discoveries, including the one discussed in my article. How can these women scientists be rescued from oblivion as a new type of discoverer if they are banned or invisibilized from the cover? If American Scientist wants to signal that “Women’s Discoveries Matter!,” then their portraits should appear on the cover. Pnina G. Abir-Am Belmont, MA Editors’ note: It is unusual for American Scientist to publish letters from authors about their own articles, but we wished to publicly acknowledge Dr. Abir-Am’s views. The editors of American Scientist feel that the subject of Dr. Abir-Am’s article is of great importance, which was why we worked extensively with her to produce it for the magazine and commissioned the above portrait to go with it. American Scientist has a long history of tackling intersectional issues of gender and inclusion in science. American Scientist does not repeat internal artwork on covers. In addition, the magazine has a long-standing policy of

To the Editors: I rarely read an entire issue of American Scientist, but I was attracted by the photograph of a dingo on the September– October 2020 cover and started reading about “The Elusive Dingo.” Then I went forward to “Empowering Success” (Science Policy), “Robogamis Are the Real Heirs of Terminators and Transformers” (Technologue), “What Happened to the Genoa Bridge?” (Engineering), “Why Did Chinese Farmers Switch to Wheat?” (Perspective), “A More Universal Language” (Sightings), “Natural History Collections Hold a Hidden Trove of Disease Data” (Spotlight), “Developing New Vaccines” (First Person), and “In Bulgaria, a Cave of Many Questions” (Spotlight). Fascinated by what I learned in those articles, I worked the other way from the dingo article to find the socially important “The Women Who Discovered RNA Splicing,” the humorous “Stop Me If You’ve Heard This Theorem Before,” and the extensive book reviews in Scientists’ Nightstand. Kudos to those who planned and executed this issue with its broad range of hard-science, soft-science, and historyof-science articles. Douglas Daetz Sunnyvale, CA 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]. 2021



Spotlight | Paleobotany

Ancient Fire Scars of the Petrified Forest Fossilized wood shows that ground fires were reshaping forests and influencing plant evolution more than 200 million years ago. When Bruce Byers brought home a piece of petrified wood he inherited after his father died in 2012, he didn’t plan to make it the subject of a new area of research. His father had collected the hunk of rock in Bears Ears, Utah, in the 1980s and had long used it as a doorstop. But with the 210-million-year-old fossil newly situated in his home, something niggled at Byers. The ancient log looked to him like it had a fire scar (below, on right), a wood growth formation that happens at the base of a tree in response to a low-intensity ground fire. A patch of live tissue under the bark is killed, and the tree grows scar tissue curled around the wound in response. Byers recalls, “I thought, ‘This is interesting. I’ve never heard of a fossil fire scar.’”

Although Byers had never studied ancient wood—he is an environmental consultant and has a PhD in biology— he had worked with researchers studying fire scars on modern wood in the 1980s after he had finished his graduate work. To settle his curiosity about whether anyone had found a fossil fire scar on a specimen like his dad’s, Byers started searching for research or coverage about the topic— but he didn’t turn up anything. So he called the Petrified Forest National Park and eventually got the chief paleontologist on the phone, who referred Byers to Sidney Ash, a paleobotanist who had studied the park’s ancient wood for more than 30 years and who was then a retired profes-

Some of the fossilized wood from the Petrified Forest National Park in Arizona (left) appears to have fire scars—a wood growth that forms when some live tissue is burned and dies, and scar tissue curls around the wound in response. A 210-million-year-old piece of fossil wood from Bears Ears, Utah (right), long used as a doorstop after it was collected in the 1980s, was the first documented fossil fire scar in 2014.

sor at the University of New Mexico, Albuquerque (Ash passed away last year). When Byers reached Ash, the latter responded, “What’s a fire scar?” Byers recalls, “I realized that there was this disconnect between modern fire ecologists and the paleobotanists who had been looking at fossil trees. The paleobotanists had no search image.” Even though the existence of ancient

Byers was surprised to find that no one had documented an example of a firescarred fossil tree. fires was known from studies of charcoal from this geological period and place, Byers was surprised to find that no one had documented an example of a fire-scarred fossil tree. Byers decided to get the fossilized log cut in cross section to see if the cells of the wood could still be deciphered. “In retrospect, I should’ve taken it straight away to the Smithsonian National Museum of Natural History,” Byers says. But as a self-admitted amateur at the time, he found a com-

Courtesy of Bruce Byers


American Scientist, Volume 109

mercial stone cutter and a the park’s permission) for woundwood granite countertop polisher preparation and analysis. overgrowth to do the job. The cut-andThe trees that grew in the polished surface revealed tropical climate of the late scar-associated band that the cells were decipherTriassic included the domiable; he could more distinctnant forest species, Agathoxly see the band of stressed ylon arizonicum, an ancient cells that can result from a extinct conifer. The specifire scar. Byers eventually men whose wood anatomy connected with the SmithByers analyzed was A. arisonian as he looked for exzonicum, as was the 2014 perts who could answer his paper ’s specimen. Byers woundwood questions about the ancient and his family team, along overgrowth wood. There, paleobotanist with the coauthors on the Dan Chaney helped Byers previous paper and dendro5 centimeters dry face of scar take images of the cells unchronologist Markus Stoffel der a microscope to send to of the University of Geneva tree-ring researcher Lucía in Switzerland, published DeSoto of the University of the results of that analysis Coimbra in Portugal, who in Scientific Reports in Noanalyzed them. vember 2020, providing Wi t h A s h , C h a n e y, more definitive evidence and DeSoto, Byers pubthat ancient fire scars may lished a description of the not be uncommon and that first- documented ancient fire likely influenced tree fire scar in 2014 in Palaeoevolution at this time. geography, Palaeoclimatology, With help from experts Palaeoecology. Other studies at the Smithsonian, Byers show that this period was cut, polished, and photoa time when the climate in graphed under a microthis area was becoming hotscope the cells around the ter and drier, and so more fire scar on the fossilized fire prone, but these studwood from the Petrified ies could not determine the Forest. He sent those imfire’s intensity, frequency, or ages to DeSoto, who meaeffects on plants. The 2014 sured the cells using treestudy was the first to show ring research protocols. 200 micrometers how a tree responded to In modern fire scars, the fire hundreds of millions of heat of a fire deforms the Fossil wood from the Petrified Forest National Park shows a years ago. elongated xylem cells that stressed band of cells characteristic of a fire scar. Analysis of the Byers’s experience con- cellular wood anatomy showed telltale signs of drought leading up conduct water, compressvinced him that it was pos- to the fire scar, compressed and collapsed xylem cells at the time of ing and collapsing them. sible that more fire-scarred the fire scar (in between the dotted lines), and a growth release af- Drought also leaves a sigfossilized wood was out terward. (From B. A. Byers et al., 2020, Scientific Reports 10:20104.) nature in the thickness of there in petrified forests of the cell walls and size of the Southwest, and no one had ever a river system on the western coast the cells, an adaptation to increase wathought to look for it. So during the of Pangea. Today the area is a desert. ter conductance when the resource is week of Halloween in 2013, in weather “It’s almost like a moonscape,” Byers scarce. A signal of drought often octhat was sunny, cold, and windy, Byers says. “It’s kind of eerie. It forces you to curs before a fire scar, whereas aftervisited the Petrified Forest National imagine jumping back in time.” ward there is generally a growth rePark in Arizona with his daughter, Only some of those petrified logs lease, when the remaining living trees Anya Byers of the Nature Conser- fossilized in a way that left the wood have an abundance of resources. vancy, and his son, Jonathan Byers of anatomy intact. Byers was interested In this ancient wood sample, they the University of Montana, to look for in one part of the park in particular. found the telltale signs of drought in more fossil trunks that appeared to “The best preserved wood, where the time leading up to the fire scar, have fire scars. some of the bases of the trunks are compressed and collapsed xylem The Petrified Forest has “thousands still preserved, is in the Black Forest cells at the time of the fire scar, and of trunks to look at,” Byers says, mak- area,” Byers says. In their weeklong a growth release afterward (see photo ing it an ideal place to look for these search of the Black Forest and several above). “The growth release duplicated fossils. The trees of the now-petrified other forests in the park, they found what we had seen in the first speciforests in Arizona and Utah grew in 13 examples, including one that, at men,” Byers explains, “but this time the Late Triassic age, between 225 mil- 31 kilograms, was small enough that we also saw the drought signal leadlion and 203 million years ago, along Jonathan Byers could lug it out (with ing up to the fire. And that seemed www.americanscientist.org




pects of cellular structure to understand whether the tree experienced drought or fire, but they could not make conclusions about the annual or seasonal frequency of these phenomena. “Our result doesn’t really tell you about the year-to-year fire regime,” Byers notes. Still, the ease with which he and his family found examples that looked firescarred suggests fire may have been common at the time. “The fact that we found three fossil fire scars in the Black Forest within half a kilometer of one another suggests that maybe that was a low-intensity fire regime forest,” Byers says. Regular, low-intensity ground

The ease with which Byers and his family found examples of fire-scarred fossil wood suggests fire may have been common at the time.

Courtesy of Bruce Byers

Bruce Byers’s son, Jonathan Byers, records the GPS coordinates of the original location of the fire-scarred fossil wood in Petrified Forest National Park, before carrying out one of the middle sections for later preparation and analysis of the wood anatomy.

unique, that in a 210-million-year-old tree you could measure a drought.” This new study by Byers and his coauthors further bolsters the evidence that low-intensity surface fires were a regular part of the late Triassic climate in the ancient Black Forest and could have favored the evolution of fire adaptations in trees. “Just based on external morphology alone, it’s pretty hard to argue that these are anything but fire scars,” Byers says, “because they are at the base of the tree and have the characteristic shape. And then we show that the wood anatomy responded in a very similar way as modern trees do.” The fossil fire scars provide insight into the size and extent of ancient forest fires, when the climate was far different from today. Tianhua He of Curtin University in Australia, an expert 8

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on ancient fire adaptations in plants who was not involved with Byers’s paper, says, “This study is an important step toward validating the role of fire as an evolutionary force from ancient times, because for the fire to be an agent of natural selection, it has to be recurrent across many, many cycles. This is the first study that demonstrates a fire happened in a dry season after a long, wetter period.” He says future studies could build on this one by looking for more evidence of recurrent fire in ancient fossilized forests. Like many trees that grow in tropical climates without strong seasons, A. arizonicum trees did not develop annual tree rings, which can be used to research frequency of fire, drought, and other climatological variables. Without these rings, the researchers could study as-

fires would have allowed some forest trees to survive burns—circumstances that could favor the evolution of particular plant adaptations. Modern trees that are adapted to fire share a suite of characteristics, including thick bark, a proclivity to resprout from stumps, self-pruning of lower branches to leave a crown protected from low fires, and, for conifers, cones that open after fire (conifers evolved earlier than flowering trees). There is little fossil evidence for these traits, and not much research attention has focused on the subject. “Someone should make a deliberate search for fossil wood, fossil cones, fossil bark, and so on that show fire adaptations,” Byers recommends. He also wonders if fire scars have been overlooked in other petrified forests in the world. “I think you would find something if you went to a place like Argentina’s fossil forests and repeated the quick reconnaissance that we did in the Petrified Forest,” he says. Now that Byers and his coauthors have tenaciously established this crucial link between fire ecology and paleobotany, the potential has been unlocked for further exciting insights into ancient fires and the evolutionary history of trees.—Katie L. Burke

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Infographic | Eleanor Spicer Rice and Kailey Whitman

Glacial Gumshoe Carli Arendt is making tracks in understanding how glaciers store and release water. Glaciers, the largest freshwater reserves on the planet, recharge aquifers, maintain ecosystems, and provide nearly half of the planet’s drinking water. During warmer months they normally melt a little, but warm seasons are growing increasingly longer as our climate changes. Arendt, an assistant professor of marine, earth, and atmospheric sciences at North Carolina State University, used naturally occurring uranium isotopes to understand how long water can be stored in and released from glaciers.

Arendt worked on the Athabasca Glacier in the Canadian Rockies. The glacier, which is about 6 kilometers long and covers about 6 square kilometers, is between 90 and 300 meters thick and loses about 5 meters per year through melting.

—Eleanor Spicer Rice

Uranium-238 decays to uranium-234 and radon-22 at a consistent rate. Arendt measures the proportions of these decay products in meltwater to understand how long water was stored.

“As climate change continues, glacial water stored for 10,000 years may now be stored for only hundreds of years. We need to understand what will happen to depleted aquifers in the future,” Arendt says.

“Glaciers fertilize the food chain,” Arendt says. Plants and animals depend on the nutrients and water from glacial melts. Salmon time their spawning events to glacial melts for more water and nutrients.

As glaciers rub against bedrock, they remove nutrients and release them downstream. The muddier the water, the more nutrients it contains. Kailey Whitman/NC State Magazine


American Scientist, Volume 109

First Person | Stephen J. Pyne

Fire Management in an Age of Contagion

Your work examines American political development through the lens of fire. What are some changes that are well told through the story of fire?

The story begins in 1910 with the Great Fire (centered in Idaho and Montana). The Forest Service was a very young agency composed almost wholly of young men who were influenced in deep and traumatic ways by that fire, and that trauma stayed with the agency and got sort of coded into its DNA. All the chief foresters up through 1939 were personally on the fire line. Two decades later, the New Deal made the Forest Service project possible, because the Civilian Conservation Corps granted bottomless amounts of labor that had to be put to work. Some of it sort of mindlessly, but a lot of it—we created an infrastructure for fire management almost overnight. After World War II there was all this war surplus equipment. Where does it go? It goes to the Forest Service and to the state cooperators to wage war on fire. We were in a kind of Cold War on fire, and there was military funding behind a lot of our fire behavior research: How do we defend ourselves from large fires, and how do we start large fires? But at some point, all the fires start looking the same: It’s pictures of big flames. How does this flame have any different meaning from that flame? They all merge together, and there’s no deeper public engagement. www.americanscientist.org

For the next 15 years, the Forest Service did what it was supposed to do: It created a national infrastructure to remove as much fire as possible from the landscape. By the 1960s, however, it was clear that this approach was a

“The fire equivalent of an ice age is an apt analogue for what’s coming. It shows the magnitude of the problem and puts the power source where it should be: fire in the hands of humans.” mistake. We were taking out good fires as well as bad fires, and we were creating conditions that were getting worse. We wanted to stop all the bad fires, but leave the good fires. This is not a new argument. We spent half of our history

Courtesy of Arizona State University

In fall of 2020, while most of the United States was focused on the spread of the coronavirus disease 2019 (COVID-19) pandemic and on preparing for the presidential election, the West faced the additional crisis of a record-breaking wildfire season. Fires stretched along the Pacific Coast, and smoke spread across the entire region, turning the sky an eerie orange. Although the pandemic, the election, and the wildfires might seem to be separate events, Stephen J. Pyne sees connections between them. Pyne, an emeritus professor of environmental history at Arizona State University, researches the history and management of wildland and rural fire. He says that examining how communities and frontline workers respond to contagions such as COVID-19 may offer a new lens through which to tackle the problem of megafires in the West. Pyne discussed the history of fire management in the United States and the possibility of analogous approaches to managing wildfires and pandemics with Scott Knowles, a historian of risk and disaster at Drexel University, on Knowles’s daily podcast, COVIDCalls. On the podcast, Knowles speaks with experts about the latest research and the far-reaching effects of the pandemic. Guests include epidemiologists and public health experts as well as social scientists, historians, and artists. This interview is the first in a collaboration between American Scientist and COVIDCalls. It has been edited for length and clarity. trying to take fire out, and the other half trying to put the necessary fires back in. Why don’t we have more to show for it? By the 1980s, fire research was practically extinguished. The whole project was about to be eliminated through privatization, and different views of government and land management came into play, which stalled the fire revolution that was in place. That mindset changed with Norman Maclean’s book, Young Men and Fire (1992). That was a real watershed moment for literature about fire. The 1994 season was our first billion-dollar suppression year, which got a lot of attention because people who previously had no interest in fire had read Maclean’s book, and they saw the South Canyon (Colorado) fire through the prism of that book. It changed the whole discourse. Now we’re in a position where we’re trying lots of things. There are places where we really need to keep fires out of communities. How do we do that? There are a lot of places that really, really need fire back in because they’re ecologically deteriorating, they’re stockpiling fuels, and they’re becoming uninhabitable. How do we deal with that? And now a larger environmental crisis, the climate emergency, is acting as a performance enhancer and globalizer for all these other trends—and we need to deal with that too. 2021



Wikimedia Commons

It’s so dire and so strange that we have no narrative to connect this coming future with our past. We have no analogues. I approach it as a historian, and I see a narrative of humanity and fire. It’s our unique narrative. Earth is a fire planet, and we’re the only creatures that can manipulate it. You have said that we’re entering the Pyrocene, a period of Earth’s history in which fire is the dominant shaping force. How can that framework help explain what we’re seeing around us?

For me, the transition from burning what I think of as living landscapes— living and dead biomass on the surface—to burning fossil biomass, or what I call lithic landscapes, changed our relationship to the world. Climate is the most obvious expression of that change, and it provides a narrative, identifying us as the prime movers and responsible agents. A fire equivalent of an ice age is an apt analogue for what’s coming. A lot of things seem to crystallize, and it shows the magnitude of the problem. It puts the power source where it should be: fire in the hands of humans. We often treat disasters as separate events, but bringing different types of disasters into one frame may help 12

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Smoke from the North Complex fire dimmed the sky and gave San Francisco an orange glow on September 9, 2020. Fire historian Stephen J. Pyne says that poor air quality from smoke will become a seasonal problem as wildfires burn the landscape every late summer and fall. Firefighters are already showing signs of respiratory illnesses, and the COVID-19 pandemic has exacerbated the problem.

us understand them as a compound problem. I feel like that’s happening right now with the COVID-19 pandemic (see “COVID-19 Reveals a Path Forward on Climate Change” on our Macroscope blog). How can you use this Pyrocenic thinking to crystallize the compound disasters in ways that people can wrap their minds around?

Climate change is acting as a performance enhancer on stuff that’s already out there. Places that already have fire, such as California and Australia, are seeing more savage versions of it, and fire is starting to come to places that haven’t had it, such as the Amazon and Indonesian peatlands that shouldn’t be having it at this scale. But I also think it points to our interaction with nature—broken biotas, if you will. Don’t emergent diseases typically arise where people are intervening in places unwisely, and then propagate outward? That’s what we’ve done with many landscapes with fire. We’ve broken it, so we’ve made it worse.

There’s an interesting analogue between megafire and emergent disease. Fire is an odd entity. It’s a reaction, and in many ways it’s not unlike a virus. We tend to think of fire as a physical, chemical reaction that has nothing to do with life. But life created oxygen; life created the fuels. Fire depends on that and propagates through biomass. Fire is not alive, but it relies on and propagates through the living world. Fire spreads as a contagion, and you can model it as a contagion. Maybe we’ve done what we can with the physical model, which only invites physical responses. If we thought of fire as a landscape equivalent to a virus, how would we respond to it? Would we just be dumping retardant on it and scraping away all the living biomass from places? Or would we be thinking, “Hey, how do we work with these landscapes? How do we think ecologically to make things more stable?” It would suggest a different suite of approaches and a different mindset. Maybe we should think of fire as a

public health problem, not just as a physical disaster (see “Coexisting with Wildfire,” July–August 2016). The spread of COVID-19 models the inequalities and vulnerabilities that already exist in American society. Thinking analogically to fire, should we be thinking about fire protection in the same way, and looking for inequalities and weak points rather than developing a national strategy?

Fire acts as a catalyst; it integrates everything. My image of fire is as a driverless car. People always ask me, “What’s driving the megafires?” Well, everything. It’s just barreling down the road, integrating everything around it. At different times and places, different aspects loom larger, and each of those aspects is a possible point of intervention. In other words, there is not one big thing we have to fix before we can deal with it. But that also means that there are a lot of other problems that we need to fix anyway that would also go toward fixing fire. Why do we have power lines starting fires? That’s a technical fix (see “Pulling the Plug on Climate Change Wildfires,” November–December 2020). Why do we have communities burning? We solved the problem of burning cities a long time ago, but we didn’t keep up the vaccinations and the hygiene and the public health model. We just said, “This doesn’t happen anymore.” It’s like polio coming back, or a massive measles outbreak, or a new epidemic spilling out, such as COVID-19. That analogy gives us a different way of thinking about fire, which suggests that there are other ways of responding. In some ways, all analogies fail, but consider house protection, for example. Most houses are taken out by embers, not by a tidal wave of flames washing over communities. Well, hardening houses against embers is like wearing a mask against aerosols. It creates what we call defensible space, which looks a lot like social distancing. It’s a social problem. If you take measures but your neighbors don’t, you’re still at risk. We don’t have a vaccine for fire, but maybe it’s like flu shots: It’s not perfect, and they’re always changing, but it gets better. That approach uses a different set of models than just saying, “We need more fire engines and air tankers.” I’m suggesting some other ways to think www.americanscientist.org

about fire because the way we’re doing it—as a war—is failing. The dominant disaster paradigm of any one time is how we view all the other hazards. As you were saying earlier, when we were fighting the Cold War, the forest looked like another front in the war. Do you see an opening here to view wildfires through the lens of the pandemic?

Firefighting using the current model and the science we have to support it isn’t solving the problem of managing fire on landscapes. We need another way of thinking about it. If we think about fire differently, what other kinds of solutions come up? It’s a way of going at the issue sideways instead of just bashing our head against the wall. We’ve reached a point where the current approach doesn’t work.

“Fire is an odd entity. It’s a reaction, and in many ways it’s not unlike a virus. Fire is not alive, but it relies on and propagates through the living world.” California has an implacable nature, which is prone to explosive fires, and the people there are determined to live where and how they choose. They’ve relied on fire agencies to stand as a buffer between nature and society, but we’ve reached the point where that doesn’t work anymore. Even the fire agencies say, “We can’t protect you under extreme conditions.” We need to think through the problem differently. I’ve been suggesting a contagion model, a public health or emergent disease model. It works out fairly well, and it might propose other ways to go at this. On COVIDCalls, I spoke with Luke Montrose, a professor of community and

environmental health at Boise State (episode 129, September 18, 2020). He talked about the public health realities for the fire crews. Many firefighters already have upper respiratory problems, and then you layer the risk of COVID-19 on top of that. Is their condition a preview of what average people living in fire-prone places could experience from smoke inhalation?

Smoke is becoming a real trigger point because it extends the range of the fire far beyond the flaming front. The Clean Air Act (1970) was effective in removing a lot of air pollution, but now it’s coming back. Again, we are watching the return of something that had gone away. We have to recognize that there’s going to be a lot more fire in the future, and a lot more smoke. We’re going to have smoke as a seasonal nuisance in the same way you have seasonal allergies. People might wear masks during part of the season. The crew situation is interesting. There were a lot of efforts before the fire season started to try to protect crews from COVID-19. We are trying to prevent large, massive fires with huge numbers of fire crews living in camps. I was struck by the oddity that for the Great Fire of 1910, the Forest Service rallied about 9,500 firefighters to send out in the Northern Rockies, plus they used most of the standing military in the Pacific Northwest. That’s comparable to numbers we’re sending out today. Doesn’t that seem odd? Despite all of our science, all of our technology, all of our communication, and all of our advances, we’re sending out the same numbers of people. Are the fires that much worse? Or is there something about the way we think of fire, and have a culture of fire, that depends on large numbers of people? The COVID-19 pandemic provides an opportunity to experiment. Why don’t we start substituting equipment? Why don’t we start experimenting with other ways to do the job that don’t require large numbers of people in camps? Why don’t we take COVID-19 as an opportunity to experiment with modern technologies and to think about all the ways we could substitute for people? Maybe that would give us some different insights into managing these fires. We’re presented with an opportunity. Let’s use it. Am


A podcast interview with the researcher is available online.





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/index.jsp

AI Detects COVID-19 from Cough Artificial intelligence (AI) can accurately diagnose coronavirus disease 2019 (COVID-19) infections by listening to recordings of people coughing. Engineers at the Massachusetts Institute of Technology set up a website where people uploaded cell phone recordings of themselves coughing. More than 5,300 people submitted recordings, which the researchers used to train and test their model. Their algorithm accurately diagnosed 98.5 percent of positive infections and had only 5.8 percent false positives. But where the model shines is in detecting asymptomatic cases, 100 percent of which were correctly identified, though with a higher rate of 16.8 percent false positives. These findings suggest that AI could be employed for cheap, noninvasive, realtime diagnoses of COVID-19. Laguarta, J., F. Huerto, and B. Subirana. COVID-19 artificial intelligence diagnosis using only cough recordings. IEEE Open Journal of Engineering in Medicine and Biology. doi:10.1109/OJEMB.2020.3026928 (September 29, 2020).


Europa’s Icy Luminescence Radiation from Jupiter may cause its moon Europa to glow in the dark. Planetary scientist Murthy S. Gudipati of NASA’s Jet Propulsion Laboratory and his colleagues created an ice analogue of Europa to test how high-energy electron radiation from Jupiter’s magnetic field would interact with the moon’s surface. They found that the crust of salt and ice that encases Europa would emit a glow visible to the naked eye. The brightness and color of the moon’s aura—slightly green, blue, or white—would depend on the mix of local materials, so studying the glow could reveal information about 14

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the surface composition. Europa is of particular interest to astronomers because beneath that layer of ice and salt lies a vast ocean that could have conditions suitable for life. Previous studies have found that water plumes from the ocean erupt through the ice, so examination of the moon’s surface glow may reveal clues about what’s happening underneath. Luckily a closer look is already in the works: NASA’s Europa Clipper mission, which is set to launch in the mid-2020s, will execute multiple flybys. The spacecraft will take images of Europa through multiple filters to identify the chemical composition of the surface.

Adolf Peretti, who discovered the fossil. The skull is only 12 millimeters long and includes a thin bone connected to its neck with preserved tongue tissue on the end. The researchers suspect that the creature used a sit-and-wait hunting style, whipping its tongue out of its mouth to catch

Gudipati., M. S., B. L. Henderson, and F. B. Bateman. Laboratory predictions for the night-side surface ice glow of Europa. Nature Astronomy doi:10.1038/s41550-020-01248-1 (November 9, 2020).

passing prey. Fossils of Albanerpetonidae are rare, and previous studies of specimens had suggested that the creatures were underground burrowers similar to salamanders. This finding upsets that theory and places their lineage closer to that of modern chameleons.

Crystals Make Magma Explode Violent volcanic eruptions may be amplified by nanocrystals in magma. Geophysicist Danilo Di Genova of the University of Bayreuth in Germany led an international team of Earth scientists in studying how these tiny, crystalline grains of iron, silicon, and aluminum—referred to as nanolites— affect the molten rock. They found that the nanolites increase magma’s viscosity, which makes it more difficult for gas bubbles to escape through the liquid layer. As the trapped gasses accumulate, they build pressure beneath the magma until they escape in an explosive eruption. Understanding how nanolites affect magma can help researchers predict switches in volcanoes’ explosive styles, which may enable communities to prepare for eruptions. Di Genova, D., et al. In situ observation of nanolite growth in volcanic melt: A driving force for explosive eruptions. Science Advances doi:10.1126/sciadv.abb0413 (September 23, 2020).

Earliest Known Ballistic Tongue Some prehistoric amphibians had fast, flycatching tongues. The skull and some soft tissue of a newly discovered genus and species in the extinct family of amphibians called Albanerpetonidae was found in Myanmar and preserved in amber for 99 million years. The paleontologists who studied the tiny creature named it Yaksha perettii—the genus derives from a type of spirit in some Eastern belief systems that guards treasures hidden in the Earth, and the species honors Swiss mineralogist

Daza, J. D., et al. Enigmatic amphibians in mid-Cretaceous amber were chameleon-like ballistic feeders. Science doi:10.1126/science .abb6005 (November 6, 2020).

Lion Genetic Pool Is Shrinking Habitat fragmentation in Africa is separating lion populations, leading to a decrease in genetic diversity. Geneticists Caitlin J. Curry and James N. Derr of Texas A&M University led a team that compared the DNA of modern lions to that of lion specimens in natural history museums that were collected in the 19th and 20th centuries. They found a significant decrease in genetic diversity in DNA passed through the male lineage, though not in mitochondrial DNA diversity, which is passed down maternally. The sharp decline only in the paternally inherited DNA makes sense given lions’ behavior: Female lions tend to stay close to the pride where they were born, whereas male lions are more likely to roam and join new prides. Habitat fragmentation has cut off access to parts of lions’ traditional terrain, so lion populations are confined to smaller islands of land in which they can roam (see “Connecting Habitats to Prevent Species Extinctions,” May–June 2019). Curry, C. J., B. W. Davis, L. D. Bertola, P. A. White, W. J. Murphy, and J. N. Derr. Spatiotemporal genetic diversity of lions reveals the influence of habitat fragmentation across Africa. Molecular Biology and Evolution doi:10.1093/molbev/msaa174 (July 15, 2020).

Edward L. Stanley/ Florida Museum of Natural History


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Subtle as a Flying Hammer


he cartoonish, elongated skull of the hammerhead shark looks so much like a wing—the structure’s technical name, cephalofoil, means “head wing”— that many researchers and shark enthusiasts have wondered if it also acts like one, generating underwater lift or improving maneuverability. A study of the hydrodynamics of the cephalofoil, published in the journal Scientific Reports, has now provided an answer, and produced the eyecatching images below as a bonus. Matthew Gaylord, a graduate student at the University of Mississippi, and his colleagues began the study by taking a bunch of severed shark heads obtained from a fishing tournament to a laser scanning laboratory at a nearby engineering facility. But this method rapidly required modification, because sharks, which have urea in their blood, smell extraordinarily bad when they’re dead, and the engineers at the facility weren’t happy about it. Eventually Gaylord and his y colleagues settled on making their x own plaster and silicone molds of z these shark heads to scan instead. The team was able to make molds



pressure –0.4













and take digital scans of eight species of hammerhead sharks; they then ran fluid-dynamics computer models on the scans to study how water flows around the hammerhead’s strangely shaped face. The team found that the cephalofoil does seem to allow for increased maneuverability, which wasn’t surprising: “Based on what I’ve seen with hammerhead sharks moving underwater, they’re just so nimble; they can change direction much faster than other sharks,” said Glenn Parsons, a biologist at the University of Mississippi and a study coauthor. In earlier studies, the cephalofoil was shown to be useful in pinning prey to the ocean floor, and to help with sensory systems, so the head has several adaptive applications. But does the cephalofoil provide lift? It doesn’t, as it turns out. The beautiful pressure diagrams at left and below show a negative result: If the cephalofoil were providing lift, the bottom of the head would be red (high pressure) and the top would be entirely green and blue (low pressure), but the red is only in front, not underneath. “We consider that a myth busted!” Gaylord said. –David Shiffman




pressure –0.4











Pressure measurements on molds of the heads of 11 species of shark (eight hammerhead species in A–H, three reference sharks in I–K; top view at left, bottom view at right; a focus on Sphyrna lewini, top) show the absence of lift generation. Warmer colors indicate higher pressure; a combination of higher pressure below and lower pressure above the cephalofoil would indicate lift. 16

American American Scientist, Scientist,Volume Volume109 109


Images courtesy of Matthew Gaylord and Glenn Parsons, from Scientific Reports 10:14495.

Does the hammerhead shark’s funky head shape give it a lift underwater?

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Could Infections Make Us Vulnerable to Alzheimer’s Disease? Mounting evidence suggests that this neurodegenerative disease could be caused by inflammatory immune responses to pathogens that afflict brain tissue. Islam Hussein


n early 2019, one of my colleagues asked me a question over lunch that I’d never considered: Could antiviral drugs be useful for treating Alzheimer’s disease? I had been studying compounds that target viruses including influenza, Ebola, and Zika for many years, and more recently I had been focusing on a drug to inhibit herpesviruses. My colleague’s question sent me on a new path, introducing me to a fascinating and controversial hypothesis linking chronic viral infections to the development of chronic, debilitating brain degeneration, and to the enormous strains that it places on patients and their families. My interest in Alzheimer’s disease isn’t solely scientific. Like tens of millions of families around the world, my family struggles with this disease. My mother-in-law cares for her sister, who was first diagnosed three years ago, and all of us are frustrated by the lack of effective Alzheimer’s therapies. Affected individuals become highly dependent on their caregivers, and they may survive in this devastating condition for more than a decade, placing enormous burdens on families and on health care systems. Currently, there are about 47 million patients with Alzheimer’s disease worldwide, and this number is projected to increase to 65 million in 2030 and more than 130 million by 2050.

After that fateful 2019 conversation, I read avidly, poring over papers on the controversial infection hypothesis of Alzheimer’s disease. For decades most scientists working on Alzheimer’s disease have called it a disease of faulty brain proteins. But it’s becoming increasingly clear that the proteins found in the brains of patients with this neurodegenerative disease might not be its sole cause. The infection hypothesis turns this idea on its head. Infection and immune response might be the true culprit, and the proteins might be a protective response rather than a dangerous cause. The Protein Problem Associated with aging and the most common cause of senile dementia, Alzheimer’s disease involves irreversible degeneration of neurons in specific brain regions, particularly those involved with memory. In 1906, Alois Alzheimer, a psychiatrist in Munich, Germany, first documented the disease through a case study of postmortem brain tissue samples from a patient named Auguste Deter, who died at age 55 after suffering from progressive dementia, severe personality changes, and memory loss. Alzheimer discovered that Deter’s smoothly interconnected network of brain neurons was interrupted by intensely stained extracellular insoluble protein aggregates

or deposits, now known as amyloid plaques. He also noticed intracellular neurofibrillary tangles that were later shown to be composed of pTau, a protein decorated with many phosphate groups. Today, these two pathological changes are considered diagnostic of Alzheimer’s disease. (See Finding Alzheimer’s Disease, March–April 2010.) But even after more than a century, scientists still struggle to understand the causes of Alzheimer’s disease. Since the 1980s, most scientists have agreed that one of the proteins in the plaques, amyloid beta (Aβ), was the root cause of the disease—an idea known as the amyloid cascade hypothesis. They reasoned that Aβ, a protein fragment made of around 40 amino acids, generated from the larger amyloid precursor protein whose function is poorly understood, accumulates in the brain as we age. Scientists proposed that the Aβ protein is a waste product of some unknown process involving this larger protein. In young, healthy people, the cerebrospinal fluid, the clear nourishing liquid surrounding our brains, can flush away Aβ. But if it is not removed efficiently, Aβ can aggregate, sticking together like Lego pieces, to form bigger insoluble structures, known as oligomers, which are harder to clear from the brain. As we age, the clearing mechanism can no longer keep up with production of waste

QUICK TAKE Most Alzheimer’s disease researchers have supported the amyloid cascade hypothesis, but mounting evidence suggests we don’t have the full story about what causes Alzheimer’s.


American Scientist, Volume 109

A few researchers suspect other disease mechanisms, such as the theory that amyloidbeta might be a response to infection or other toxins, an immune protection that went too far.

The infection hypothesis will be difficult to prove, but more researchers are exploring the idea in hope of finding ways to stop and reverse cognitive decline from Alzheimer’s disease.

Aβ, and the oligomers gradually accumulate. According to this hypothesis, oligomer buildup eventually leads to plaques, damages neurons, and disrupts transmission of nerve signals in sensitive areas responsible for memory in the brain. That damage eventually results in the cognitive decline and memory loss associated with Alzheimer’s disease. Believing that Aβ was the disease’s root cause became dogma in this field, and drug developers went after it with drugs that reduce its levels in the brain. But this approach has repeatedly failed: After hundreds of clinical trials over the past 30 years, compounds that deplete Aβ have shown limited therapeutic benefit and do not significantly improve cognitive function in patients with Alzheimer’s. Clearly, the

in the brains of patients with Alzheimer’s. Aβ appears to be more than a junk byproduct. Rather, it seems to play an important protective role in the brain, one that was being disrupted by the Aβ-fighting drugs. The Infection Paradox Even as the amyloid cascade hypothesis was first being established, other evidence suggested that the Alzheimer’s story was more complex. In the early 1980s, Melvyn Ball, who was then a pathologist at University Hospital in London, Ontario, proposed a different idea about the cause of Alzheimer’s disease. He argued that reactivation of a latent herpes simplex virus type 1 (HSV-1), which infects up to 90 percent of humans, could be involved in the disease.


Plaques of amyloid beta (Aβ), a protein fragment, glom together within the brains of people with Alzheimer’s disease. Researchers are still trying to figure out why these plaques form and how they disrupt memory and brain function. One emerging theory is that Aβ plaques might form to protect the brain from infections.

amyloid cascade hypothesis has flaws, and researchers need to rethink what might be causing this disease and how they might treat it. In addition, some patients in those clinical trials suffered from side effects. Most notably, they were more susceptible to encephalitis, brain inflammation typically caused by an infection. This unexpected finding offered a hint about what might really be happening www.americanscientist.org

His ideas were inspired by studies of brain tissue: He had examined samples from the brains of patients who had survived herpes simplex encephalitis, a rare complication of that infection, and noticed that the affected areas of their brains resembled tissue from patients who had Alzheimer’s disease. Ball’s iconoclastic hypothesis didn’t capture much attention at first. Viruses and other pathogens rarely penetrate

the brain because of the immune protection afforded by the blood–brain barrier. The blood vessels that feed the brain are lined with tightly interconnected endothelial cells, which restrict the size and identity of molecules and cells that can gain access to this tissue. Bacteria, parasites, and even viruses are mostly blocked by those cells, so most researchers considered it unlikely that infection could have significant effects on the brain. Despite this extra defense, a small group of microorganisms, including herpesviruses, can penetrate the brain either by infecting peripheral nerves or through a weakened blood–brain barrier. Twenty years later, in 2002, Ball’s ideas got a boost from Australian neurologists Stephen Robinson and Glenda Bishop. They proposed that their colleagues had misinterpreted the significance of the Aβ aggregates in the brains of patients with Alzheimer’s. Robinson and Bishop argued that protein plaques and tangles could be a protective immune response, binding to and sequestering a variety of toxic substances—including metal ions, proteins, and microbes—for removal from the brain; the researchers called it the bioflocculant hypothesis. In this view, Aβ aggregates could be helpful. The pair expected other researchers to attack them mercilessly, but they were surprised that most commentaries on their work agreed that the amyloid cascade hypothesis was flawed. Robinson and Bishop’s work made researchers rethink the potential role of Aβ, but it didn’t make a clear case for what was causing harm in the first place. Even with Ball’s earlier observations, the idea that certain chronic viral infections might be involved in Alzheimer’s didn’t just run in opposition to the notion that Aβ caused this disease. It also faced headwinds in the virology community because it violated key parts of Koch’s postulates, a set of principles designed by physician Robert Hermann Koch and bacteriologist Friedrich Loeffler in the 19th century to establish that a microbe causes a disease. Those postulates require that the infectious microorganism be isolated from a diseased organism, cause disease when introduced into a healthy organism, and then be identified as the same organism in that new subject. But HSV-1 infects about 90 percent of the population and often could not be detected in the brain tissue of people who died of 2021



Alzheimer’s disease. Evidence linking cause and effect was lacking, and finding such evidence would be difficult. However, several research groups studied the role that microbial infections could play in Alzheimer’s disease, building the case for the infection hypothesis. Ruth Itzhaki of the University of Manchester and her colleagues observed that Aβ accumulates in cell cultures and in the brains of mice infected with HSV-1. As researchers followed up on this initial work, several groups reported evidence that HSV-1 could be involved in Alzheimer’s disease. In 2009, Itzhaki’s group showed that HSV-1 DNA is specifically localized within Aβ plaques from slices of human brains. But the link is still circumstantial evidence. They didn’t find whole viruses and couldn’t confirm a causal connection. HSV-1 is a stealthy virus; it can hide in nerves to avoid immune surveillance. But under certain conditions— compromised immunity or stress exposure— it can reactivate and replicate. Most

often it produces harmless cold sores, but it can also migrate up the peripheral nerves to the brain. In the brain, HSV-1 can go latent again and reactivate periodically, causing mild subclinical encephalitis. Though a causal

Even though a causal link remains difficult to establish, growing evidence shows that something within Alzheimer’s brains, most likely amyloid, has powerful antiviral effects. link between HSV-1 and Alzheimer’s disease is difficult to prove, it’s plausible that gradual cumulative damage from the virus eventually could be manifested at a late stage in life as Alzheimer’s disease, as Ball observed in the early 1980s.

microglia microbe

infections provoke release of molecules called cytokines neuron plaque sets off more inflammation amyloid precursor Barbara Aulicino

plaque traps microbe

amyloid beta (Aβ)

immune response boosts enzyme that produces Aβ

The Alzheimer’s disease infection hypothesis proposes that amyloid beta (Aβ) plaques that collect in the brain are an immune response gone awry. If a virus reaches the brain or an infection is reactivated, it could prompt the tissue to release immune molecules called cytokines. Those immune molecules could trigger the release of an enzyme that cleaves the amyloid precursor protein into the shorter fragments, Aβ, which form plaques to help mark the infectious agent for removal. But if the plaques remain, they can trigger more inflammation and protein buildup in the brain tissue, leading to memory loss and other dementia symptoms. 20

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For researchers trying to understand how infection might spur Alzheimer’s disease, the work was an uphill battle. Most of the neurology community had invested in the amyloid cascade hypothesis and still believed that ongoing clinical trials would produce an effective therapy. Despite evidence that pathogens could cross the blood–brain barrier and that Aβ could be an immune response, the idea didn’t fit the conventional notion of an infectious disease. In a 2018 article in STAT, Massachusetts General Hospital researcher Robert Moir, one of the early pioneers in this field, described the mixed reviews on research articles and grant applications, hampering his ability to pursue this research. I met Moir a few months before he died in 2019 and he told me how hard it was for him to get his initial paper published. Although he submitted what is now considered a key paper about the antimicrobial activity of Aβ to the highest impact scientific journals, it was rejected several times before being published by PLOS ONE in 2010. Strengthening the Link But even though a causal link remains difficult to establish, growing evidence shows that something within Alzheimer’s brains, most likely amyloid, has powerful antiviral effects. Over the past two decades, the list of microbes linked to Alzheimer’s disease has expanded. In addition to viruses such as HSV-1, the two other human herpesviruses, HHV-6 and HHV-7, bacteria such as Borrelia burgdorferi and Chlamydia pneumoniae, and fungal pathogens such as Candida albicans have all been linked with Alzheimer’s disease, through a range of studies using cell culture, animal models, and human brain tissue. By 2011, Itzhaki’s group had revealed in cell culture that infections could trigger Aβ deposits and showed how those deposits might be protecting the brain. When they infected cultured human neurons with HSV-1, levels of Aβ and pTau within the cells increased. Treating those infected cells with antiviral drug acyclovir, which curbs HSV-1 replication, lowered the amounts of Aβ and pTau. In a second experiment, synthetic Aβ inhibited HSV-1 replication— but only when pre-incubated or mixed with virus, not when added later. These results suggested that Aβ could prevent the virus from infecting the neurons in the first place. Another study by Robert Moir showed that homogeneous

Biophoto Associates/Science Source

Herpes simplex virus type 1—a common virus that causes cold sores—is one of a growing list of microbes linked with Alzheimer’s disease. As early as the 1980s, Canadian pathologist Melvyn Ball observed that the brain tissue from patients with herpes encephalitis, a rare infection complication, resembled brain tissue from patients with Alzheimer’s disease.

fluid mixtures from the whole brains of patients who died of Alzheimer’s disease had antimicrobial effects against the fungus Candida albicans. Moir had started working on the infection hypothesis after he observed striking structural similarities between Aβ and LL-37, another small protein with known antimicrobial properties in the human brain. In 2010, he showed that synthetic Aβ had antimicrobial activity under laboratory conditions against eight bacterial and fungal pathogens with a potency that was equivalent to or even higher than LL-37. Moir’s group followed up that work with studies in animal models. They genetically engineered a transgenic strain of mice to over-express human Aβ and injected their brains with the bacteria Salmonella typhimurium. Strikingly, those transgenic mice were protected and survived for significantly longer than their wild-type counterparts. The strongest evidence so far linking infection and plaques came in 2019 from a study in mice done by a group of Italian researchers. They showed that repeated cycles of HSV-1 reactivation in mice triggered the progressive accumulation of Aβ and pTau in the brain regions primarily affected by Alzheimer’s disease, eventually leading to cognitive www.americanscientist.org

decline in infected animals. This scenario supports the notion that HSV-1 infection is a risk factor for Alzheimer’s disease and that Aβ could be the innate immune system’s response. After reaching a critical threshold concentration, however, Aβ could switch from being protective to neurotoxic. Epidemiological studies are also highlighting links between chronic infection and Alzheimer’s disease. In a longitudinal study of 512 elderly French people, a group of researchers found in 2008 that individuals who tested positive for HSV-1 IgM antibodies, associated with primary infection or reactivation, had a 2.5-fold higher risk of developing Alzheimer’s disease than those without antibodies. More recently, in 2018, a larger study of 33,000 people from Taiwan’s National Health Insurance Research Database showed that the risk of dementia was 2.5-fold higher among the more than 8,000 people aged 50 and older who had been diagnosed with herpes simplex virus infections. In addition, a subset of the infected group who had been treated with antiviral drugs later showed a 10-fold reduction in dementia compared to infected but untreated patients. This result doesn’t absolutely prove a causal link, but it’s among the strongest circumstantial evidence available to support the infection hypothesis for Alzheimer’s disease. Becoming Mainstream Despite the accumulating pieces of evidence, some scientists remain skeptical about the Alzheimer’s infection hypothesis. They note that researchers have detected herpesvirus DNA in brain tissue from patients with Alzheimer’s, but that the DNA does not prove that the live virus was active in the brain. Because herpesviruses mostly remain in a latent form, isolating live virus from such tissue is challenging. But other organisms implicated in Alzheimer’s disease, such as Borrelia burgdorferi and Chlamydia pneumoniae, have been cultured from patient brain tissues. Skeptics also question the link between HSV-1, a virus that’s widespread, and a disease that occurs in a much smaller fraction of the population. Clearly, infection alone can’t explain Alzheimer’s disease; genetics must be a factor as well. Genetic studies have shown that many patients with Alzheimer’s disease, perhaps 60 percent, carry the type 4 allele of the apolipoprotein E gene. This gene is involved

in lipid transport and repair of tissue damage, and one leading hypothesis proposes that this protein could be involved in the creation or clearance of Aβ aggregates. Though its role in Alzheimer’s disease pathogenesis is not clearly understood, people who carry this allele might have altered or even faulty mechanisms for repairing damage from HSV-1 reactivation in the brain. Nevertheless, the infection hypothesis is gaining ground, as amyloid-focused therapies keep hitting a dead end and as researchers find more links between viral exposure and Alzheimer’s disease. Major research foundations and government funding agencies, such as the NIH’s National Institute on Aging, now issue requests for proposals for research that investigates the infection hypothesis. There is also progress toward new Alzheimer’s therapies based on treating infection. For example, a Phase II clinical trial is underway in New York testing valacyclovir, an antiviral drug for herpes, in more than 100 individuals with mild Alzheimer’s disease who are also infected with herpes simplex virus. Results are expected in 2022. But scientists are a long way from understanding exactly how to solve the Alzheimer’s puzzle. For example, it’s unclear how findings that link dementia with chronic infection might connect to other newer hypotheses about Alzheimer’s disease, such as the role of diminished blood flow (see “Angiogenesis, Aging, and Alzheimer’s Disease,” March–April 2016). If the brain’s response to infection proves to cause Alzheimer’s disease, we’ll need to better understand exactly how Aβ works and how the whole disease process is triggered. Ultimately, researchers would like to understand Alzheimer’s disease and its progression well enough so that they can screen healthy populations for a combination of risk factors, such as antibodies, genes, or other early biomarkers. If they could pair that knowledge with therapies that halt, or even reverse, brain tissue damage at that critical stage, clinicians could offer significant hope for individuals and families like mine who face the challenges of this cruel disease. (References are available online.) Islam Hussein is a virologist and a senior scientist at Microbiotix, a biopharmaceutical company specializing in antimicrobial drug discovery. His research aims to discover and develop novel antiviral drugs for treating several viral diseases. Email: [email protected] 2021




A Bicentennial in a Pandemic Union Bridge in the United Kingdom had to celebrate its milestone virtually in 2020, but its historical significance remains steadfast. Henry Petroski


he coronavirus pandemic has changed, at least temporarily and maybe permanently, the nature of engineering and scientific discourse. Face-to-face meetings and conferences—for centuries, if not millennia, the customary ways for new ideas and developments to be communicated among thinkers and scholars— have become things of the past. And the change took place as rapidly as COVID19 spread throughout the world. My experience with the COVID-19 pandemic was set in motion about six months before it reached its fever pitch last spring. In September 2019, I was invited to deliver the keynote address at the national conference of the American Society of Highway Engineers, to be held in Raleigh, North Carolina, in June 2020. But at the end of March, the conference was rescheduled as a smaller, virtual event without a keynote. At that time, travel became difficult as well; an archivist from the Huntington Library in San Marino, California, happened to be visiting me, and he experienced difficulty securing a return flight to California. Since then, I have participated in meetings via Skype, Zoom, and other virtual platforms, but, at least at the beginning, they were not at all as satisfying as being in a conference room or auditorium interacting with colleagues in real time. In virtual meetings, I have been frustrated by low-quality sound and picture, poorly synchronized video and audio, and confusion about when to respond to a question because of transmission delays. And going virtual has interrupted events other than meetings. Henry Petroski is the Distinguished Professor Emeritus of Civil Engineering at Duke University. Address: Box 90287, Durham, NC 27708. 22

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Building a Shortcut Organizers of long-planned gala events have had to make their own difficult decisions about postponing, or going virtual to whatever extent possible. A particularly disappointing situation arose in the United Kingdom, where a celebration of the bicentenary of a historically significant bridge across the River Tweed had been planned for at least six years. Union Bridge connects Horncliffe, England, the country’s most northerly village, with Fishwick, Scotland, the site of a long-vanished medieval village whose name survives as that of the local parish. In the mid-1990s, as part of our tour of bridges in England, Scotland, and Wales, my wife and I drove across the bridge, and I can attest that it appeared to be in the middle of nowhere. The area is indeed sparsely populated, with Horncliffe having the largest concentration of population: 400 was the 2011 census count. By contrast, 12,000 people live in Berwick-upon-Tweed, located 8 kilometers to the northeast, at the mouth of the Tweed. By today’s standards, this short distance, combined with Fishwick’s distance of 11 kilometers to the west, makes even people familiar with the area wonder why Union Bridge was built where it was in the first place. One speculation is that the bridge made it convenient to move coal and lime from the pit mines in Northumberland, in which Fishwick is located, north to Berwickshire, where they were used to fertilize farmland. In the early 19th century, depending on the condition of the roads, traveling even 23 kilometers in a horsedrawn, heavily laden wagon was no trivial matter. Rain turned dirt roads to mud, and deep ruts developed when the roads dried out. Such hindrances

to transportation, and hence to defense and commerce, had driven the development of improved road surfaces since ancient times. Great strides in road design were made in France and Britain during the 18th and 19th centuries. Two Scottish engineers of note, who no doubt influenced the later work of the builder of the Union Bridge, are Thomas Telford and John McAdam, and they made especially significant contributions not only to roads but to infrastructure generally. Thomas Telford, who was born into poverty in rural Scotland in 1757, became apprenticed at age 14 to a stonemason. As he advanced in the craft, he also absorbed through self-study and observation the elements of design and construction generally, which at that time was a common route to becoming an engineer. In time, he was given the responsibility to design canals and the masonry viaducts that carried them over wide valleys. He also worked in the new bridge-building materials of cast and wrought iron. Among his masterpieces are the Pontcysyllte Aqueduct in Wales and the Menai Strait suspension bridge, which like the Union Bridge featured wrought-iron chains. In London, he was responsible for the St. Katherine Docks. His broad achievements in what during his career became known as civil engineering made him a natural choice as first president of the Institution of Civil Engineers, which was founded in 1818. John McAdam, a contemporary of Telford, was born into more comfortable circumstances. At age 14, he was called to New York to work in his uncle’s merchant business. McAdam stayed in America for about a dozen years, after which he returned to Scotland as a man

Jim Gibson -The Friends of the Union Chain Bridge

Union Bridge, which spans the River Tweed between Horncliffe, England, and Fishwick, Scotland, employs eyebar links to form suspension chains (right). The bridge appears remote now, but at the time it was built, it likely connected farms to fertilizer mines. The bridge opened in 1820, and a bicentennial celebration was planned for last year. The coronavirus pandemic forced the planners to be creative in coming up with ways of conducting the celebration virtually.

of means. He operated a colliery that supplied fuel to the tar trade. This experience no doubt prepared him well for his position as a trustee of a turnpike company, in which capacity he became increasingly involved with overseeing road construction. This experience and his subsequent involvement with another turnpike company led to his development of a new method of using crushed stone to form a road pavement, which came to be known eponymously as macadamisation, the basis of what today is known as macadam. (Adding a coat of tar to a macadamized surface resulted in a “tar macadam” one, which came to be shortened to the now familiar “tarmac.”) By the early 19th century, the superiority of British roads had become well known. In 1820, when Danish physicist Hans Christian Ørsted toured Europe, lecturing on his experiments with electricity and magnetism, he found the turnpike roads over which he traveled by coach to London to be “as smooth as a dance floor.” It is unlikely that the country roads leading to and from the Northumberland coal and lime mines were that smooth, and so building a toll bridge that would save a heavily laden wagon a round trip of 23 kilometers to cross the Tweed must have sounded like a good investment. www.americanscientist.org

Cost Versus Structure A primary decision faced by anyone wishing to invest in a river crossing then, as now, is what kind of bridge to choose. Stone bridges constituted a long-established form, but because of the extensive labor involved, they could be expensive. Iron arch bridges that mimicked stone ones had been erected in England since 1779, when the famous one at Coalbrookdale was completed. As the name of that Shropshire village implies, it was located in an area that was a source of fuel. It was also an area where iron ore was mined. This combination made it natural to smelt the ore in the nearby blast furnaces that had been established by the British ironmaster Abraham Darby in the early 1700s. The resulting iron fueled the Industrial Revolution. The first cast-iron bridge spanned 30 meters across the River Severn and was unimaginatively named Iron Bridge, a name soon associated also with the settlement at one end of it. To save on transport from the foundry, components of the semicircular arch bridge were cast on the banks of the river, and the half arches were hoisted into place and joined in no time, compared to the time required to set stones for an equivalent span.

An arch is an ideal structure to make out of cast iron because the material is strong in compression. Before long, semicircular cast-iron arch bridges developed into ones flatter in profile and longer in span. However, the material is not as strong in tension and is brittle. Wrought iron, on the other hand, with its lower carbon content, is about equally strong in compression and tension and is ductile, so it was a natural material to use for resisting the pull applied to chains. The first wrought-iron chain suspension bridge was built not in England but in America, in 1810 at Newburyport, Massachusetts. The 75-meterspan Chain Bridge was designed by Philadelphia engineer James Finlay and built by John Templeman. Its total cost was $25,000, or about £5,000 at the fairly constant 19th-century exchange rate. According to Thomas Pope’s 1811 Treatise on Bridge Architecture, the bridge had “passage-ways of fifteen feet [4.5 meters] in width each, and the floor is so solid as to admit of horses, carriages, etc. to travel at any speed, with very little perceptible motion of the floors. The railing is stout and strong, which adds much firmness to the floor.” According to an 1820 report in The Scotsman, then a fledgling newspaper out of Edinburgh, a stone bridge be2021



Professor Roland Paxton

An engraving by Robert Scott, from an 1822 painting by Thomas Sword Good, shows wagon traffic on Union Bridge, the first suspension bridge in Europe to carry vehicles.

tween Horncliffe and Fishwick would have cost “upwards of £20,000.” In contrast, an iron-chain bridge—a suspension bridge—was estimated to cost £5,000. That was the price for which Captain Samuel Brown, of the Royal Navy, was expected to construct a bridge employing iron chains derived from technology he had developed for use on ships and at piers. He based the design of a major suspension bridge in part on patents he acquired in 1817 for the use of chain links. (Telford reviewed and generally approved of Brown’s designs.) Brown’s bridge chains were made up of 4-meter-long, 5-centimeter-diameter eyebar links joined by iron pins. In all, 12 chains were draped between towers 133 meters apart. Iron rods were hung from the chains to support a 6-meterwide roadway stiffened by a railing. All this iron, plus the weight of the roadway itself and the traffic on it, created an enormous pull on the chains, which had to be resisted by robust anchorages if the bridge was to succeed. In the Union Bridge, on one end the chains were attached to iron plates buried in the ground, and on the other they were socketed into a cliff. The bridge took about a year to build, and its final cost amounted to £7,700. Then, as now, construction projects came in over budget. The bridge was opened on July 26, 1820. At the time, it was the longest suspension bridge in the world and the first in Europe to carry wagon traffic. According to The Scotsman, several scientists in attendance “admired very much this curious specimen of the arts.” Appropriately, the first person to cross 24

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the bridge was Brown, who by doing so signaled his faith in the bridge he had created. He rode in his curricle, a twowheeled open carriage. Brown was followed by 12 carts heavily loaded with stones, demonstrating the ability of the span to bear the weight of the coal- and lime-laden wagons it was designed to carry. After this assurance, bands playing the national anthem led dignitaries across. Finally, a crowd of about 700 people, who had been watching with some skepticism about the ability of the bridge to withstand the weight placed upon it, surged onto the bridge in celebration.

When it opened, Union Bridge was the longest suspension bridge in the world and the first in Europe to carry wagon traffic. Bicentennials Only Come Once The Friends of the Union Chain Bridge organization wished to recreate such a joyous celebration two centuries later. But when their long-standing plans to celebrate the 200th birthday of the bridge were dashed by circumstances surrounding the coronavirus pandemic, they sought to salvage what they could of the festivities. Among the

public events scheduled for the evening of the bicentenary was a ceilidh—a social event of early 19th-century Scottish music and singing with traditional dancing and storytelling. The canceled event is expected to be rescheduled in conjunction with a 2021 music festival. Other planned celebrations were modified for virtual participation. The symposium that had been planned for the day of the bicentenary did not go virtual electronically, but it did in the time-tested manner of a printed volume. Because symposium speakers had submitted synopses of their presentations in advance, there was enough time to collect them into a book published in conjunction with a vastly toned-down celebration. The volume bears a title worthy of a centuries-old monograph: Spanning the Centuries: An Anthology of Essays Reflecting the Influence and Heritage of the Union Bridge, Berwick-upon-Tweed, to Celebrate Its Bicentenary. The collection is edited by Roland Paxton of the Institute for Infrastructure and Environment at Edinburgh’s Heriot-Watt University. He is a civil engineer and historian who possesses the most outstanding collection of historical engineering documents and books that I have seen outside an institutional library. One live event that did escape cancelation took place at the bridge on its birthday: the unveiling of a plaque declaring the Union Chain Suspension Bridge an International Historic Civil Engineering Landmark. The honor is a joint effort of the Institution of Civil Engineers, the American Society of Civil Engineers, and the Japanese Society of Civil Engineers. The inscription includes details of the engineering achievement, of course, but it also rec-

Washington Imaging/Alamy Stock Photo; Border Image/Alamy Stock Photo; Sally Anderson/Alamy Stock Photo; The Friends of Union Chain Bridge

Union Bridge bears many plaques and symbols commemorating its connecting two countries. An early marker (top right) shows the rose of England intertwined with the thistle of Scotland. A plaque from 1930 (top left) recognizes a restoration to strengthen the bridge cables. A banner (bottom left) announced the bicentenary, and a permanent plaque (bottom right) proclaims international recognition of the bridge’s historical significance.

ognizes that the bridge unites England and Scotland over the River Tweed using Welsh ironwork, thus making it a collaboration among three of the countries making up the United Kingdom. At its opening, the bridge also bore a recognition of the England–Scotland connection by means of cast-iron plaques with the Latin motto “Vis Unita Fortior” (“United Strength Is Stronger”) inscribed beneath a symbolic rendering. Each plaque, as shown on a contemporary etching of the bridge, seems to depict a pair of hands shaking before some indistinct flora, and was evidently meant to be attached to the bridge chains at midspan, much the way a bridge or tunnel today might display the exact dividing line between the political jurisdictions it connects. As does many a conceptual design, before it was cast in iron, the Union Bridge marker seems to have been modified to bear above the words only an intertwined rose and thistle, the traditional symbols of the respective countries. Around www.americanscientist.org

1871, perhaps to foil souvenir hunters, such as those who may have made off with an earlier version, each plaque was relocated from the railing of the bridge to a place high on each tower. Today, Union Bridge still epitomizes the objectives of civil engineering as articulated in the 1828 application for a royal charter by the Institution of Civil Engineers. The document was drafted by English engineer Thomas Tredgold, and the relevant passage defines “the profession of a Civil Engineer” as “the art of directing the great sources of power in Nature for the use and convenience of man, as the means of production and of traffic in states, both for external and internal trade, as applied in the construction of roads, bridges, aqueducts, canals, river navigation, and docks, for internal intercourse and exchange; and in the construction of ports, harbours, moles, breakwaters, and lighthouses, and in the art of navigation by artificial power, for the purposes of commerce.” The field played then, as it

does now, a key role in the development of infrastructure that is so essential to a nation’s economic well-being. Union Bridge owes its existence to the need to move coal and lime from where they were mined to farmland that they could improve. It was built to fulfill the economic need for an improved means of travel. A cost–benefit analysis determined that it was a sound business decision to pay a toll to cross a bridge that reduced the time and wagon-maintenance expense exacted through the use of free but poor roads. The original purpose of the bridge hasn’t lasted. But having stood for 200 years, the bridge has certainly withstood an immense number of social and infrastructural changes. The resilience of its bicentennial celebrations in the face of a pandemic is a fitting testament to its steadfastness over time. Bibliography Dalton, A. 2020. The day crowds feared opening of Tweed bridge. The Scotsman July 19, p. 12. Paxton, R., ed. 2020. Spanning the Centuries: An Anthology of Essays Reflecting the Influence and Heritage of the Union Bridge, Berwick-upon-Tweed, to Celebrate Its Bicentenary. Berwick-upon-Tweed: Friends of the Union Chain Bridge. Pope, T. 1811. A Treatise on Bridge Architecture. Published by the author. pp. 171–173. 2021




The Dark Past of Algorithms That Associate Appearance and Criminality Machine learning that links personality and physical traits warrants critical review. Catherine Stinson


hrenology” has an oldfashioned ring to it. It sounds like it belongs in a history book, filed somewhere between bloodletting and velocipedes. We’d like to think that judging people’s worth based on the size and shape of their skulls is a practice that’s well behind us. However, phrenology is once again rearing its lumpy head, this time under the guise of technology. In recent years, machinelearning algorithms have seen an explosion of uses, legitimate and shady. Several recent applications promise governments and private companies the power to glean all sorts of information from people’s appearances. Researchers from Stanford University built a “gaydar” algorithm that they say can tell straight and gay faces apart more accurately than people can. The researchers indicated that their motivation was to expose a potential privacy threat, but they also declared their results as consistent with the “prenatal hormone theory” that hypothesizes that fetal exposure to androgens helps determine sexual orientation; the researchers cite the much-contested claim that these hormone exposures would also result in gender-atypical faces. Several startups claim to be able to use artificial intel-

ligence (AI) to help employers detect the personality traits of job candidates based on their facial expressions. In China, the government has pioneered the use of surveillance cameras that identify and track ethnic minorities. Meanwhile, reports have emerged of schools installing camera systems that automatically sanction children for not paying attention, based on facial movements and microexpressions such as eyebrow twitches. University students taking online exams monitored by proctoring algorithms not only have to

answer the questions, but also maintain the appearance of a student who is not cheating. These algorithms reportedly make false accusations against students with disabilities who move their faces and hands in atypical ways, and Black students have indicated that they have been required to shine bright lights in their faces so as to have their features detected at all. Perhaps the most notorious recent misuse of facial recognition is the case of AI researchers Xiaolin Wu and Xi Zhang of Shanghai Jiao Tong

QUICK TAKE An increasing number of artificial intelligence (AI) technologies claim to be able to find associations between appearance and character traits better than humans can.


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However, the generalizations that these algorithms make can often be explained by factors that do not relate to genetics, such as social presentation.

Rather than producing objective insights, researchers are cautioning that AI programs are often reinforcing human biases and could harm already marginalized populations.

University, who claimed to have trained an algorithm to identify criminals based on the shape of their faces, with an accuracy of 89.5 percent. The 2016 work has appeared only as a preprint, not in a peer-reviewed journal. The researchers didn’t go quite so far as to endorse the ideas about physiognomy and character that circulated in the 19th century, notably from the work of the Italian criminologist Cesare Lombroso: that criminals are under-evolved, subhuman beasts, recognizable from their sloping foreheads and hawklike noses. However, the study’s seemingly high-tech attempt to pick out facial features associated with criminality borrows directly from the “photographic

over time. In the 19th century, phrenology’s detractors objected to the fact that the practice attempted to pinpoint the location of different mental functions in different parts of the brain—a move that was seen as heretical, because it called into question Christian ideas about the unity of the soul. Interestingly, though, trying to discover a person’s character and intellect based on the size and shape of their head wasn’t perceived as a serious moral issue. Today, by contrast, the idea of localizing mental functions is fairly uncontroversial. Scientists might no longer think that destructiveness is seated above the right ear, for instance, but the notion that cognitive functions can be localized in particular brain circuits is a standard assumption in mainstream neuroscience. Phrenology had its share of empirical criticism in the 19th century, too. Debates raged about which functions resided where, and whether skull measurements were a reliable way of determining what’s going on in the brain (they’re not). The most influential empirical criticism of old phrenology, though, came from French physician Jean Pierre Flourens’s studies based on damaging the brains of rabbits and pigeons—from which he concluded that mental functions are distributed, rather than localized. (This result was later re-interpreted.) The fact that phrenology was rejected for reasons that most contemporary Courtesy of Rachael E. Jack; from Jack et al., 2016. observers would no longer acAt the center of many machine-learning algorithms trained to classify human faces is facial recog- cept makes it only more difficult to fignition software, itself designed to make generalizations about the emotions tied to human expres- ure out what we’re targeting when we sions based on facial movements. Shown above in red, from left to right, are the areas deemed use phrenology as a slur today. central to happy, sad, surprised, and angry faces. Research shows that humans, even toddlers, tend Both “old” and “new” phrenology to make snap judgements from a photo, and wrongly overgeneralize from a single expression to a have been critiqued for their sloppy person’s overall character. Artificial intelligence algorithms may be perpetuating this bias. methods. In the recent AI study of criminality, the data were taken from two composite method” developed by Yet when algorithms are dismissed very different sources: ID photos providVictorian jack-of-all-trades Francis with labels such as ”phrenology” or ed by police forces for convicts, versus Galton—which involved overlaying “pseudoscience,” what exactly is the professional photos scraped from the inthe faces of multiple people to find the problem being pointed out? Is phrenol- ternet for nonconvicts. Pictures that peofeatures indicative of qualities such as ogy scientifically flawed? Or is it morally ple willingly post on the internet tend health, disease, beauty, or criminality. wrong to use it, even if it could work? to show them in rather different moods, Technology commentators have clothing, and life circumstances than in panned these facial-recognition tech- Flawed Data Sets ID photos. Those facts alone could acnologies as “literal phrenology”; There is a long and tangled history to count for the algorithm’s ability to detect they’ve also linked some applica- the way the word phrenology has been a difference between the groups. Simitions to eugenics, phrenology’s parent used as a withering insult. Moral and larly, critics of the gaydar algorithm repseudoscience that aims to “improve” scientific criticisms of the endeavor search point out that there is an obvious the human race by encouraging people have always been intertwined, al- explanation for why it is not hard to tell deemed the fittest to reproduce, and though their entanglement has changed apart the pictures of gay and straight www.americanscientist.org

discouraging childbearing in those deemed unfit. Galton himself coined the term eugenics, describing it in 1883 as “all influences that tend in however remote a degree to give to the more suitable races or strains of blood a better chance of prevailing speedily over the less suitable than they otherwise would have had.” China’s surveillance of ethnic minorities has the explicit goal of denying opportunities to those deemed unfit. Technologies that attempt to detect the faces of criminals or exam cheaters may have more noble goals, but tend to lead to the same predictable result: a lot of false positives for already marginalized people, leading to the denial of rights and opportunities.




it stigmatizes people who are already overpoliced. The authors of the criminality paper say that their tool should not be used in law enforcement, but cite only statistical arguments about why it ought not to be deployed. They note that the false-positive rate is very high (more than 95 percent of people it classifies as criminals have never been convicted of a crime), but take no notice of what that means in human terms. Those false positives would be individuals whose faces resemble people who have been convicted in the past. Given the racial and other biases that exist in the criminal justice system, such algorithms would end up overestimating criminality among marginalized communities. Courtesy of the Wellcome Collection

Attempts to locate key aspects of appearance that indicate a person has a criminal nature have a long history. This set of photos is taken from The Delinquent Woman from 1893 by Italian criminologist Cesare Lombroso, and shows his physiognomies of Russian female criminals. Lombroso believed that criminality was inherited and that criminals had “subhuman” features.

people that the study took from dating sites: They tend to be dressed, made up, and posed differently. Even the angle from which the picture was taken can account for changes in face shapes. In a new preface to the criminality preprint, the researchers also admitted that taking court convictions as syn-

Some commentators argue that facial recognition should be regulated as tightly as plutonium, because it has so few nonharmful uses. onymous with criminality was a “serious oversight.” Yet equating convictions with criminality seems to register with the authors mainly as an empirical flaw, in that using pictures of convicted criminals, but not of the ones who were cleared, introduces a statistical bias that skews the results. They said they were “deeply baffled” at the public outrage in reaction to a study that was intended “for pure academic discussions,” which also suggests an unawareness that their work’s flaws go beyond sloppy statistics. Notably, the researchers don’t comment on the fact that being convicted of a crime itself depends on the im28

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Try, Try Again? The most contentious question seems to be whether reinventing phrenology is fair game for the purposes of “pure academic discussion.” One could object on empirical grounds: Eugenicists of the past such as Galton and Lombroso ultimately failed to find facial features that predisposed a person to criminality. That lack of evidence is almost certainly because there are no such connections to be found. Likewise, psychologists who studied the heritability of intelligence, such as Cyril Burt and Philippe Rushton, had to play fast and loose with their data to make it look like they had found genuine connections between skull size, race, and IQ. If there were anything to discover, presumably the many people who have tried over the centuries wouldn’t have come up dry. Complex personal traits such as a tendency to commit crimes are exceedingly unlikely to be genetically linked

pressions that police, judges, and juries form of the suspect—making a person’s “criminal” appearance a confounding variable. They also fail to mention how the intense policing of particular communities, and inequality of access to legal representation, skew the data set. It is utterly unsurprising to find differences in appearance between people who are arrested and convicted and those who are not. As Ice Cube famously argues, the Los Angeles Police Department thinks every Black man is a drug dealer. In their response to criticism, Wu and Zhang don’t back down on the assumption that “being a criminal requires a host of abnormal (outlier) personal traits.” Indeed, their framing suggests that criminality is an innate characteristic, rather than a response to social conditions such as poverty or abuse, or a label applied to exert social control. This assumption mirrors the gaydar study’s quick leap to the conclusion that it must be picking up on something biological. Part of what makes the data set questionable on empirical grounds is that who gets labeled “criminal” is hardly value-neutral. A 2016 preprint from Chinese researchers claimed a machineOne of the strongest learning algorithm could distinguish between a set of ID moral objections to us- photos of criminals (examples in top row) and noncriminals ing facial recognition to (bottom row). The study has been highly criticized by other detect criminality is that artificial intelligence researchers. (From Wu and Zhang, 2016.)

Courtesy of Margaret Mitchell

Researchers from Google AI, Blaise Agüera y Arcas (left) and Margaret Mitchell (right), along with Alexander Todorov of Princeton University (middle), took photos of their own faces with consistent lighting and background, but with grooming, expression, and camera angle more common in photos of either heterosexual (left set) or homosexual (right set) dating site photos, to establish that generalizations from machine-learning algorithms about face shapes and other physical aspects of these photos can be attributed to social presentation cues, not genetics.

to appearance in such a way as to be readable from photographs. First, criminality would have to be determined to a significant extent by genes rather than environment. There may be some very weak genetic influences, but any that exist would be washed out by the much larger influence of environment. Second, the genetic markers relevant to criminality would need to be linked in a regular way to genes that determine appearance. This link could happen if genes relevant to criminality were clustered in one section of the genome that happens to be near genes relevant to face shape. For a complex social trait such as criminality, this clustering is extremely unlikely. A much more likely hypothesis is that any association that exists between appearance and criminality works in the opposite direction: A person’s appearance influences how other people treat them, and these social influences are what drives some people to commit crimes (or to be found guilty of them). The argumentative strategy Wu and Zhang use—of claiming that we ought to be able to look at the evidence with a detached academic eye even when people’s lives hang in the balance—was pioneered by prominent eugenicist and statistician, Karl Pearson. In a recent article on this subject, mathematician Aubrey Clayton argues that statistical significance testing was designed to give a mathematical sheen to eugenic claims that only flawed methods could prop up: “By slathering it in a thick coating of statistics, Pearson gave eugenics an appearance of mathematical fact that would be hard to refute.” Using these (utterly common, but increasingly maligned) statistical methods, Wu and Zhang can offer results that are, techniwww.americanscientist.org

cally speaking, statistically significant, but nevertheless highly misleading. AI algorithms seem to have even more power than math to bamboozle.

the force of the complaint. For scientists to take their moral responsibilities seriously, they need to be aware of the harms that might result from their research. Spelling out more clearly what’s wrong with the work labeled “phrenology” will hopefully have more of an impact than simply throwing the name around as an insult. Bibliography

Do No Harm The problem with reinventing eugenic methods such as phrenology cloaked in new technological guises is not merely that it has been tried without success many times before. Researchers who persist in looking for cold fu-

Artificial intelligence algorithms seem to have even more power than math to bamboozle. sion after the scientific consensus has moved on also face criticism for chasing unicorns—but disapproval of cold fusion falls far short of opprobrium. At worst, cold fusion researchers are seen as wasting their time. The difference is that the potential harms of cold fusion research are much more limited. In contrast, some commentators argue that facial recognition should be regulated as tightly as plutonium, because it has so few nonharmful uses. When the deadend project you want to resurrect was invented for the purpose of propping up colonial and class structures—and when the only thing it’s capable of measuring is the racism inherent in those structures—it’s hard to justify trying it one more time, just for curiosity’s sake. However, calling facial-recognition research “phrenology” without explaining what is at stake isn’t the most effective strategy for communicating

Agüera y Arcas, B., M. Mitchell, and A. Todorov. 2017. Physiognomy’s new clothes. Medium, May 6. Agüera y Arcas, B., A. Todorov, and M. Mitchell. 2018. Do algorithms reveal sexual orientation or just expose our stereotypes? Medium, January 11. Clayton, A. 2020. How eugenics shaped statistics. Nautilus, October 28. Graves, J. L. 2002. What a tangled web he weaves: Race, reproductive strategies and Rushton’s life history theory. Anthropological Theory 2:131–154. Jack, R. E., et al. 2016. Four not six: Revealing culturally common facial expressions of emotion. Journal of Experimental Psychology: General 145:708–730. Kshetri, N. 2020. Remote education is rife with threats to student privacy. The Conversation, November 6. Stark, L. 2019. Facial recognition is the plutonium of AI. XRDS 25(3):50–55. Van Noorden, R. 2020. The ethical questions that haunt facial-recognition research. Nature 587:354–358. Wang, Y., and M. Kosinski. 2018. Deep neural networks are more accurate than humans at detecting sexual orientation from facial images. Journal of Personality and Social Psychology 114:246–257. Wu, X., and X. Zhang. 2016. Responses to critiques on machine learning of criminality perceptions. arXiv:1611.04135 Wu, X., and X. Zhang. 2016. Automated inference on criminality using face images. arXiv:1611.04135v1 Catherine Stinson is an assistant professor of computing and philosophy, and Queen’s National Scholar in Philosophical Implications of Artificial Intelligence, at Queen’s University in Kingston, Canada. This article is adapted and expanded from one on Aeon, aeon.co. Website: https://www.catherinestinson.ca 2021



Unveiling Earth’s Wayward Twin Venus, the closest planet, seems like a hellish version of our own; studying how it got that way will tell us a lot about the prospects for life among the stars. Paul K. Byrne


hen I started studying planetary geology, I hated Venus. There’s no way to see its surface directly, because the planet is wrapped in an unbroken layer of sulfuric acid clouds. Radar can penetrate the murk, but the resulting images are so limited and ambiguous that it’s almost impossible to tease apart what exactly is going on. And forget about searching for signs of habitability in that jumble. Even though Venus is nearly the same size as Earth and orbits just slightly closer to the Sun, it is nothing like our planet. Its atmosphere consists of unbreathable carbon dioxide, so dense that it practically flows like an ocean. Temperatures on the ground resemble those inside a self-cleaning oven. But over time I have come to love the Hell Planet. I now see the complexities that once frustrated me in a different light—as clues to a fascinating, increasingly urgent set of questions. Some of those questions hit close to home. Venus formed at the same time as Earth, and is presumably made of largely the same materials. How could a world so fundamentally similar to our own have turned out so disastrously different? For a long time, most planetary scientists

assumed that Venus went off track in its early days, perhaps right after it formed. Recent studies hint at a different possibility: Venus might have been moderate, even Earth-like, for most of its life before a runaway greenhouse effect transformed it into the infernal pressure cooker it is today. Figuring out which story is correct has major implications for reconstructing Earth’s history and for predicting whether a similar process might someday devastate our planet. Studying Venus will also tell us a lot about the prospects for finding life around other stars. Exoplanet searches have identified thousands of worlds around other stars, including more than a dozen Earthsized bodies that could potentially have comfortable temperatures and liquid water. What we cannot tell, yet, is whether any of those places could actually support life. We have neither the theoretical insight nor the observational data to tell whether we live in a galaxy full of balmy Earths, or if we are surrounded by brutal Venuses. We need to get a handle on the fundamental differences between our planet and the one next door if we’re to correctly interpret what we see in other planetary systems and correctly target our search for alien life.

Venus is a planetary puzzle. It started out similar to Earth in size, composition, and distance from the Sun, yet ended up with a crushing atmosphere and a dry, lethally hot surface.

No spacecraft has explored the geology of Venus in more than three decades. A modern mission could investigate why Earth and Venus developed in such starkly different ways.

Earth-sized planets appear to be common around other stars. Venus offers clues about how many of them could actually support life, and about how a habitable planet could die.

topography of Venus (kilometers above mean surface level) =4.4

Data: NASA & USGS/ Map: © Eleanor Lutz 2017


Venus is as enticing and enigmatic to scientists today as Earth was to the early mariners of centuries or millennia ago. We have named a vast array of features that identify Venus as a world we can explore: Ovda Regio, Niobe Planitia, Metra Corona. But despite its proximity, Venus remains one of the most mysterious planets in the Solar System.





Inspired by these ideas, I’ve become a self-professed Venus evangelist. It’s not an easy job. Despite its proximity and scientific importance, Venus remains one of the least-explored planets in the Solar System. The last time NASA launched a mission there was three decades ago—three decades during which ever-more-capable spacecraft have visited Pluto, dropped probes into Jupiter, dived through Saturn’s rings, and traversed the deserts of Mars. Still, the limited information we do have about Venus provides a strong incentive to learn more. There is evidence of erupting volcanoes, shifting faults, and other geologic activity that shows what Earth might have been like without its oceans. Just in the past few months, radioA rare look at the surface of Venus, captured on March 5, 1982, by the Venera 14 lander. The original scan (below) was reprojected (right) to yield a more natural perspective. Venus’s dense atmosphere reduces sunshine to a dim, ruddy glow and causes distant objects to appear greenish. The flat plain surrounding Venera 14 is covered with rocks that resemble thinly bedded sediments. Chemical analyses suggest they might be lithified volcanic ash.


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Pull quote images courtesy of Donald P. Mitchell/Soviet space program

Lifting the Veil Venus was actually a frequent target in the early days of space exploration, starting with NASA’s Mariner 2 mission in 1962. Prior to then, Venus’s distance to the Sun led some scientists—and many science fiction writers—to envision a lush, tropical world. Mariner 2 obliterated such visions when it returned measurements of torrid temperatures in the lower atmosphere. The numbers were so high that many researchers initially found them hard to believe: The surface temperature on Venus averages 465 degrees Celsius, hotter even than the planet Mercury. Mariner 2 also found that, unlike Earth, Venus has no protective, global magnetic field. Around the same time, radar measurements from a radio

antenna at the Goldstone Deep Space Communications Complex in California showed that the rotation of Venus is retrograde: It spins in the opposite direction that it orbits the Sun, unlike all other planets except Uranus. Equally weird, it takes 243 Earth days for Venus to complete a single turn, by far the slowest of any planet in the Solar System. In 1967, the Soviet Union’s Venera 4 probe plummeted into the Venusian atmosphere and took the first in situ measurements of its composition. The probe revealed that the atmosphere is 96.5 percent carbon dioxide, with negligible water vapor, and so thick that the surface pressure is 90 times that of Earth. The Soviet Union continued its focus on Venus, with Venera 8 in 1972 establishing that the planet’s brilliant, silvery clouds are largely composed of corrosive sulfuric acid droplets. Although Venus is bone dry today, apparently that was not always the case. Subsequent space missions measured the abundance of two forms of hydrogen—regular hydrogen and deuterium, which is chemically identical but twice as massive—and discovered

Courtesy of Donald P. Mitchell/Soviet space program

Magellan showed us a world with a vast array of volcanic and tectonic features, including some bizarre structures not seen anywhere else in the Solar System.

telescope studies have revealed tentative hints of peculiar chemistry, and possibly even biological activity, within Venus’s clouds (see box on page 36). For us to truly understand the rules governing Earth-sized worlds in general, and our own Earth in particular, it’s clear that we must return to Venus. We have a lot of catching up to do.


Composite VIRTIS (images, left), AKATSUKI-UVI (image, right)/JAXA/ESA/J. Peralta, JAXA/R. Hueso, UPV/EHU.

The Venusian atmosphere is like an ocean of carbon dioxide, trapping solar energy and producing complex flows. Viewed in thermal infrared by Japan’s Akatsuki probe (upper left), the planet’s nightside glows with heat. Clouds appear as dark silhouettes; changes in color correspond to variations in particle size or composition. Akatsuki also discovered a 10,000-kilometer-long standing wave (left) in the cloud tops. The upper atmosphere circles Venus every four days, 60 times as fast as the planet rotates. The Akatsuki and Venus Express probes studied this phenomenon, called superrotation (upper right).

213 223 233 brightness temperature (K) Courtesy of ISAS/JAXA

that Venus’s atmosphere contains about 100 times as much deuterium relative to hydrogen as Earth’s does. Because Venus lacks a magnetic field, water molecules drifting into its upper atmosphere can be split apart into their constituent atoms and then stripped away by the solar wind. Deuterium, being more massive than regular hydrogen, is preferentially left behind by this process. The abundance of deuterium implies that the planet once possessed far more water than it does today. NASA’s Pioneer Venus mission, which deployed four atmospheric www.americanscientist.org

probes in December 1978, confirmed the intense temperatures and pressures measured by the earlier Soviet missions and reported back extreme variations in wind speed. The most complete information about Venus’s atmosphere came from the final Soviet missions, Vega 1 and 2, in the mid-1980s. Both were headed to Halley’s Comet, but along the way they flew past Venus, and each deployed a balloon probe and a lander. The balloons inflated and operated for more than a day, bobbing along at an altitude of about 55 kilometers, where the temperature and pressure are fairly close to those at sea level on Earth. During that time, the fierce high-altitude winds carried the balloons 11,000 kilometers, and their onboard accelerometers recorded dramatic up- and downdrafts. The main Vega spacecraft stopped relaying balloon data to Earth when they passed out of range, so nobody knows for certain how long the balloons operated before their batteries ran out. The Vega 1 and 2 landers operated on the Venusian surface as well, but they

were far from the first to do so. That honor belongs to the Soviet Venera  7 probe, which on December 15, 1970, touched down on Venus and returned a trickle of data despite being damaged on impact. Two years later, Venera 8 made the first fully successful touchdown, and broadcast a host of scientific measurements during its 50 minutes of life on the ground. All told, the Soviet Union landed 10 spacecraft on Venus, yielding the first images from the surface of another planet (Venera 9 in 1975), as well as the first off-world sound recording (Venera 13 in 1982). None of the landers returned data for more than two hours in the searing heat, but they were able to determine that the rocks on Venus are primarily basaltic, similar to much of the surfaces of Mercury, Mars, and the Moon, as well as the oceanic crust on Earth. Because Venus’s thick atmosphere and acidic clouds make it impossible to see the surface from above in visible light, NASA’s Pioneer Venus orbiter (which arrived in 1978 and operated until 1992) and the Soviet Venera 15 2021



Courtesy of Paul Byrne

Radar views of Venus were captured by the Magellan probe and reprocessed by the author. Brighter, yellower colors correspond to surface material that is rough at radar wavelengths or that faces the incoming beam. Left to right: A chain of volcanoes, or “shield field”; Maram Corona, a distinctively Venusian structure, which may indicate where a huge rising plume of hot rock deformed the crust; Markham crater, an impact surrounded by a lopsided flow of melted rock or ejecta; and a portion of Ovda Regio, one of Venus’s elevated tessera regions. The images are 370 kilometers, 700 kilometers, 550 kilometers, and 800 kilometers wide, respectively.

and 16 missions (which made orbit in 1983 and functioned for eight months) scanned the planet with radar. Those missions found evidence of extensive volcanic deposits and tectonic deformation, most notably in heavily fractured and folded tesserae, broad highlands that appear older than the lavas that surround them—although it was difficult to evaluate ages from those coarse images. The issue of whether Venus’s surface is ancient or young came into sharper focus with NASA’s Magellan mission, which created what are still the most

detailed radar maps of the planet over four years, starting in 1990. Magellan unveiled a world with diverse volcanic and tectonic features, including many bizarre and unfamiliar structures. Venus lacks the well-defined plate tectonics that characterize Earth. It also has no ancient terrains equivalent to the lunar highlands, Mercury’s heavily cratered plains, or the bombarded southern uplands on Mars. Instead, it is broadly organized into a set of rift systems, low-lying plains, and the isolated highlands. In short, Venus


Young volcanism on Venus? The Venus Express orbiter measured the planet’s surface emissivity, a measure of the way that materials emit infrared radiation. Several volcanic structures, including Idunn Mons (shown above), are higher in emissivity than rocks in the surrounding plains, implying that they are relatively fresh and unweathered. The Venus Express team concluded that those flows could be less than a few tens of thousands of years old, bolstering the case for modern volcanic activity on Venus—possibly even happening right now. 34

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looks utterly unlike Earth, but looks even less like any of the other rocky worlds of the inner Solar System. As a planetary geologist, I am fascinated by these unique, ambiguous landscapes. Some of my current work focuses on the tesserae, trying to deduce when and how they formed. It is possible they are so ancient that they predate the time when Venus entered its runaway greenhouse. If so, the tesserae might contain a record of the planet’s earlier environment; for instance, those regions could contain sedimentary rocks and erosion features that formed in the presence of liquid water. Unfortunately, even the Magellan images do not contain enough detail to tell for sure. I’ve also studied the geology of the rifts, which may have jostled huge blocks of crust against one another. In a recent paper, a group of collaborators and I suggested that the jumbled Venusian crust might resemble what the Earth was like 3.5 billion years ago, when the modern process of plate tectonics was just beginning. In the Magellan images, Venus looks like a planet that is still geologically active, but how active remains a matter of lively debate. Magellan’s maps turned up a surprisingly small number of impact craters: Venus has fewer than 1,000 of them, and no gigantic impact basins equivalent to those on the Moon, Mercury, and Mars. Even more unexpected, those craters appear scattered randomly across Venus, with no region more heavily battered than any other. Extrapolating from the derived rate of impacts on the Moon, the surface of Venus is no more than 750 million years old on average. In contrast, most of Mars is more than 2.9 billion years old, and the surfaces of

the Moon and Mercury have changed little in the past 3.8 billion years. Planetary scientists have developed strongly divergent views about why Venus appears so relatively youthful. Some of my colleagues theorize that the planet was wiped clean by a global-scale catastrophe, with lavas pouring out all across the globe simultaneously. Others take a more nuanced view, suggesting that volcanism was episodic and localized, either taking place over a particular phase of Venus’s life, or perhaps continuing throughout its history.

entered orbit around Venus in late 2015, although it had originally been slated to do so five years earlier. An engine failure at the start of a critical maneuver required mission engineers to design a clever but circuitous new flight path. At the time of writing, Akatsuki is still operating at Venus, monitoring the planet’s weather and characterizing the threedimensional structure of the atmosphere. It has already made several

Modern Missions and Beyond After Magellan, the exploration of Venus proceeded at a much slower pace. Russia’s space-science budget collapsed after the breakup of the Soviet Union; meanwhile, the United States decided to concentrate its efforts on Mars. The European Space Agency (ESA) filled the gap with its Venus Express mission, which entered orbit about the planet in April 2006 and relayed data until late 2014. Venus Express collected longterm measurements of the atmosphere, including its thermal structure and its interaction with the solar wind, and recorded possible evidence of lightning. The spacecraft also measured how the surface of Venus emits infrared radiation. Those observations suggested that the lava flows in some regions might be quite fresh, geologically speaking—as little as 250,000 years old. Such plausibly recent flows strongly support the view that the planet remains volcanically active today. At present, there is just a single spacecraft studying Venus: the Akatsuki probe from the Japanese Aerospace Exploration Agency (JAXA). Akatsuki

How can a world seemingly with the same starting conditions as Earth take such a vastly different path?


notable discoveries, including a 10,000kilometer-long wave centered above Aphrodite Terra, one of the planet’s highlands. The probe has also shown that thermal tides might be the driving force behind a startling phenomenon at Venus called superrotation: The upper atmosphere of the planet rotates 60 times faster than the planet itself. Venus will receive a smattering of additional attention from passing probes that use the planet’s gravity either to speed up or to slow down in route to other planetary destinations. The joint ESA–JAXA BepiColombo mission to Mercury did a Venus flyby last October, and it will do another this October.

NASA’s Parker Solar Probe and several other upcoming missions will use Venus as a planetary slingshot, too. But these are limited, intermittent opportunities; there is no dedicated spacecraft slated to study Venus itself after Akatsuki. Fortunately, that situation may soon change. Several times per decade, NASA holds open competitions for its next planetary mission. NASA centers, research institutes, universities, and industry partners propose concepts that are then evaluated to determine their scientific value and novelty, technical readiness, and likelihood of success. For decades, missions to Venus have been passed over in favor of visits to Mars, asteroids, Jupiter, and Saturn’s moon Titan. The odds look better this time around. In 2019, NASA received more than a dozen proposals for the Discovery program, which supports missions costing up to $500 million. When the agency chose four semifinalists for an additional nine-month study, two of the candidates were missions to Venus. One contender is VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy), managed by NASA’s Jet Propulsion Laboratory. It would use radar to map Venus at 10 times the spatial resolution of Magellan, resolving details as small as 15 meters, and at up to 100 times the topographic resolution of the earlier mission. If selected, VERITAS would be able to settle the debate about when and how the surface of Venus was reshaped; explore whether the tesserae formed in the presence of liquid water; and detect active volcanism and other ongoing geological changes. Such data would transform our picture of Venus. The other shortlisted NASA mission concept is DAVINCI+ (Deep 2021



Joanna Petkowska, https://www.joannapetkowska.com/

Life on Venus? Really? Venus might seem utterly hostile to life, but it could have been habitable in the distant past. Even today, its cloudtops have temperatures and pressures much like those on Earth’s surface. Given that similarity, a few researchers have wondered if strange dark material seen in its clouds, dubbed the “unknown absorber,” could be hardy alien microbes. More compelling evidence of life on Venus arrived this past September, when an international team reported a radio-telescope detection of phosphine (shown as data lines over an ultraviolet image of the planet, below), a molecule that on Earth is produced mainly by bacteria. Other scientists soon questioned the validity of the result; the team stands by its findings. Even if the phosphine signal is real, it does not prove biological activity. But current life on Venus remains an open, albeit unlikely, possibility—one more reason to give the planet a much closer look.

Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging, Plus), proposed by NASA’s Goddard Space Flight Center. In addition to an orbiter equipped with infrared and ultraviolet cameras, DAVINCI+ includes a probe that would plunge down to the planet over one of its tesserae, taking images and measuring atmospheric composition all the way to the surface. The mix of trace gases in the atmosphere should determine whether Venus really did once possess far more water than it does today. High-resolution images 36

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from the DAVINCI+ probe during its descent, in turn, would make it possible to study the formation of Venus’s highlands, and to look for the sedimentary rocks that would indicate the planet once had liquid water on the surface. VERITAS and DAVINCI+ still face steep competition from two other Discovery-class proposals, one to visit Jupiter’s volcanic moon Io, the other to fly past Neptune’s giant, Pluto-like moon, Triton. NASA is expected to announce the winner (or possibly two winners) in the spring of 2021. The U.S. space agency isn’t the only one with its eyes on Venus. ESA is considering a “Medium-class” mission concept called EnVision, a radar-mapping orbiter that would also be equipped with ground-penetrating radar to scan the planet hundreds of meters beneath the surface; the agency plans to announce its decision in the middle of 2021. The Indian Space Research Organization has proposed Shukrayaan-1, a Venus orbiter that could launch in 2025. And Russia is developing the VeneraD concept, an updated incarnation of its storied Venera probes. The D stands for dolgozhivushaya (which means longlasting), with the new lander designed to survive for a record three hours on the harsh Venusian surface. Should any of these probes fly, there’s likely to be a surge of public interest in the second planet from the Sun. We’ve seen that pattern repeatedly for Mars, as each new mission produces captivating results and a flurry of inspiring media coverage. For planetary scientists, the surge is already underway. Many of us—myself very much included—are hoping the 2020s will be “the Decade of Venus.” The Rosetta Planet The breakthrough space voyages in the 1960s through the 1980s only began to put together the pieces of the enormous puzzle that is Venus—so much like Earth, yet so dramatically not. That stark disparity leaves scientists wondering which planet is the weirdo. Perhaps Venus suffered an early, outof-the-blue catastrophe that slowed its rotation and weakened its magnetic field, leaving it defenseless against the Sun. Then again, maybe Venus is a typical midsize planet and Earth is the oddity, saved from a similar fate by an unlikely quirk of circumstance: the formation of the Moon, an unusually generous supply of water, or some other,

as-yet-unknown factor. The best way to find out is to study what Venus was like in the distant past, and to determine how it became today’s Hell Planet. After the first space probes revealed Venus’s true nature, some researchers began to theorize that the planet was not always so severe. It could have had oceans early in its history, when the young Sun was significantly less energetic and Venus received only about 30 percent more sunshine than Earth does today. In this scenario, Venus’s surface was slowly but inexorably warmed by

It may be, then, that Venus’s current state isn’t the price of being relatively close to its host star, but simply bad luck. the brightening Sun until its oceans started to evaporate too quickly to be replenished by rainfall. With a humid atmosphere trapping more and more heat, the planet’s temperature continued to climb until the oceans boiled away. At that point, its fate was sealed. Even if Venus started out wet and mild, that benign state might not have lasted long. Calculations by James Kasting of Pennsylvania State University in the 1980s indicated that Venus’s runaway greenhouse kicked in early, in the first few hundred million years of its life. Earth’s greater distance saved it from overheating, but only for a while. As the Sun continues to brighten, a similar fate could await our world about a billion years in the future. Recent work has cast doubt on this interpretation, however. In a series of studies published since 2016, Michael Way of the NASA Goddard Institute for Space Studies and his colleagues argue that Venus’s misfortune was not the fault of a changing Sun, but rather was self-inflicted. Way and his team theorize that the coincident occurrence of multiple enormous volcanic eruptions on Venus—each comparable to the one that resurfaced a huge swath of


Suzanne E. Smrekar/JPL/NASA Courtesy of James B. Garvin/NASA

northern Russia about 250 million years ago, triggering the Permian–Triassic mass extinction—was what wrecked the planet’s climate. Such eruptions would have dumped so much carbon dioxide into the atmosphere over such a short period of time that the planet’s rocks could not absorb it all. It may be, then, that Venus’s current state isn’t the inevitable result of being slightly closer to the Sun, but simply bad luck. Way’s climate models suggest that Venus could have remained habitable for up to three billion years, perhaps all the way until the time of a volcanic catastrophe. Given that simple microorganisms were present on Earth when the planet was about a billion years old (and possibly quite a bit earlier), some astrobiologists have speculated that life could have taken hold on ancient Venus as well—and even that Venusian microbes might survive to this day, floating in the planet’s clouds. That last idea, long regarded as borderline fanciful, attracted considerable attention last autumn when a team led by astronomer Jane Greaves of Cardiff University in Wales reported a controversial detection of phosphine in the Venusian atmosphere. Phosphine is a rare molecule, commonly associated with anaerobic bacteria on Earth (see box on page 36). And we can find out—if we return to Venus! Advances in spacecraft design, navigation, and instrumentation mean that a modern mapping effort would far surpass the results from Magellan. It could finally deliver the kind of highresolution images my colleagues and I have been yearning for so that we can reconstruct the planet’s geologic and climatic history in detail. An atmospheric probe like the one proposed for DAVINCI+ would vastly improve on the chemical measurements made by the Venus missions of the 1970s and 1980s. Even more exciting is the prospect of exploring Venus up close using next-generation landers or even rovers. Engineers at NASA’s Glenn Research Center are developing electronics that could operate for weeks or months at Venus surface temperatures, addressing the most daunting technological issue that limited the lifetimes of the Soviet landers. Other experimental concepts would use clockwork-like mechanisms to replace electronics entirely, or rely on slow but potent winds to move a rover around using no onboard energy. Studies of Venus also have implications that go far beyond our Solar

VERITAS (top) and DAVINCI+ (left and above) are being considered by NASA for flight to Venus in the late 2020s. VERITAS would make high-resolution radar maps and conduct spectral observations to determine the planet’s material properties and geologic history. DAVINCI+ would drop through the atmosphere over the course of an hour, gathering the compositional information needed to reconstruct Venus’s past climate.

System. Exoplanet searches have determined that our galaxy is full of warm, Earth-sized planets: A recent analysis of data from NASA’s Kepler space telescope implies that there could be hundreds of millions of them. We don’t yet have the observational capabilities to study the conditions on these strange new worlds, but the Second Planet from the Sun offers a natural, nearby laboratory for learning how Earth-sized planets form and evolve all across the universe. It can tell us why good planets go bad—and which one of these outcomes is the norm and which the aberration. If Venus is a rare misfire, then habitable, Earth-like worlds may be common around other stars.

The questions to investigate are profound. The timing is perfect, with tantalizing results from Akatsuki and planet-hunting telescopes begging for closer investigation. Four different space agencies have Venus mission concepts underway. We have the opportunity to begin a new era of exploration of the Second Planet. Will we take it? (References are available online.) Paul Byrne is an associate professor of planetary science in the Department of Marine, Earth, and Atmospheric Sciences at North Carolina State University. A geologist by training, he uses a combination of remote sensing and geospatial analytics, numerical and analogue modeling, and fieldwork to understand why planets look the way they do. He is a self-confessed Venus evangelist. Twitter: @ThePlanetaryGuy 2021



Plants as Teachers and Witnesses One plant biologist reflects on seasonal re-pacing in a culture of constant action, as a gift learned from her study subjects. Beronda L. Montgomery


ast winter, I visited McLeod Plantation Historic Site on James Island in South Carolina. When my family and I arrived at the McLeod site, the day was overcast and we could smell rain in the air. As we left the visitors center with the tour guide and rounded the path to the main entry of the plantation, my son and I broke off from the group as we all approached the “big house” directly in front of us, the gravel crunching on the dry, dusty ground beneath our feet. I looked at the abundant rain clouds and, although confident the dry grounds would eagerly soak up a downpour, I was concerned that the coming rain would lead us to a hurried exploration of the grounds, which I was most excited about, because this part of the plantation is where our enslaved ancestors would have spent the most time. In the face of rain, we would instead have to spend more time touring the house of the enslaver and former landowner. We entered the big house and followed the guided tour while keeping an eye on the sky each time we passed a window. As the tour came to an end, we were thrilled to see a small patch of blue at the edge of the storm clouds, and the rain held at bay. As we began our journey through the grounds, constantly keeping an eye on the storm clouds, we glanced first at the restored original cotton gin to the left, and then our gazes lingered on a row of original houses that had served as the living quarters of the enslaved people to the right (see page 40). After a brief stop to peer into the gin that had processed countless pounds of cotton, we entered

one of the cabins, which were unbelievably small and desolate. The stillness of the air and the emptiness of the quarters were in stark contrast to the weighty and disconcerting feelings my son and I felt when we were inside. As we stepped back outside the quarters, I was drawn to a massive tree directly ahead of us: the McLeod Oak. The tour guide said that it was believed to be upward of 600 years old. I reverently approached the tree and stood beneath its broad, sweeping branches and gently rustling leaves while my son ventured on. As the rain clouds began to fully dissipate in the distance, I stood under the oak tree, watching my son from a distance as he sat on a bench looking pensively over the cotton fields with the quarters behind him, quarters which had been built from local trees by the hands of the enslaved people themselves. Standing under the McLeod Oak, I was awestruck by the realization that this living tree had stood in this same place at a time when what could have been our own enslaved ancestors inhabited and worked this land. Although our own familial roots were in the Arkansas Delta region, upward of 40 percent of enslaved Africans in the United States entered through Charleston, South Carolina. Thus, our ancestors had likely passed through this region, and it’s possible distant relatives could have remained here. This awareness weighed heavily in my thoughts and led me to question what this oak’s life had been like, and what it had witnessed of the lives of the people living together with it on the McLeod land. I wondered

Studying how trees adapt to the seasons teaches lessons about the importance of anticipation, appropriate response, and bearing witness. Humans likewise have seasonal shifts.


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Modern humans’ capacity for constant action and overworking can be balanced with seasoninformed, survival-enhancing behaviors, such as measured engagement in work and regular periods of rest.

For deciduous trees, spring demands a burst of action, summer requires focused productivity, fall is a transition in anticipation of rest, and winter is a time of pause. We must honor these natural cycles to thrive.

Dale Powell


Keepers of the Legacy Plants, including the McLeod Oak with which I stood that day, carry evidence in their very beings of the lives of those with whom they have shared space. The carbon dioxide exhaled by animals and humans is inhaled by plants and, together with water and energy harvested from the Sun, is transformed first into sugars that sustain their lives and that build up their physical forms. Plants use these sugars to produce substances such as starch and cellulose, which in turn can be assembled into leaves and seeds, and also can be deposited into wood for trees. Trees thus carry the very essence of humans, both past and present, in their bodies and bear witness to our existence. As humans, we are also dependent upon the oxygen that plants exhale, as well as many other gifts they offer to support our lives—fruits, nuts, seeds, wood, and shade. In standing with this tree, I also stood in the presence of ancestors. Even though we were visiting in December, the McLeod Oak still bore green leaves because it is a Southern live oak tree (Quercus virginiana). Live oak trees are semideciduous evergreens that remain green throughout the year. However, in late winter or early spring, their new leaves emerge and push off the previous year’s dying leaves, replacing them. This oak reminded me of some of my very first work with plants as a burgeoning plant researcher in central Arkansas, when I investigated how light affects leaf color and development in deciduous Southern red oak trees (Quercus falcata). The Southern red oak is distinct from evergreen oaks in that it is deciduous and so responds to each season distinctly in easily observable ways: Spring finds Southern red oaks in anticipation and then a burst of action, summer marks a period of focused productivity, fall is a time when deciduous trees transition to a preparation for rest, and winter is a time of pause. I stood wondering about what the McLeod Oak must look like in spring when its new, www.americanscientist.org

bright green leaves emerge and its yellowing, older leaves wither and drop to the ground. I wondered how the pace and patterns of life of our enslaved ancestors must have changed across the seasons in parallel. Growing up in Little Rock, Arkansas, surrounded by the Southern red oaks that I later studied, I always anticipated the vast shadow cast when those trees were adorned with their many fully developed summer leaves, and the massive colorful pile of leaves they dropped in fall. Unlike the seasonally varying cycles of plants, the current human condition, including my own, is too frequently a life of constant action. My biological knowledge of plants has grown over the years as I’ve studied their responses to changes in environmental cues such as light. So, too, has my appreciation for the many lessons I can learn from these organisms. Even the observational knowledge that I have gained from watching trees survive in the intensely hot, humid summers in the South of the United States, and now seeing these organisms survive brutally cold and snowy winters from my home in the North, has instilled in me a deep appreciation for how these

“In standing with this tree, I also stood in the presence of ancestors.” organisms anticipate and prepare for changes in temperature, light availability, and other environmental signals. The long days of summer are perceived as a sign to grow abundantly, whereas the shorter, colder days of winter signal a time for rest. Studying how trees adapt to each season has taught me pointed life lessons—about the importance of anticipation, appropriate response, and bearing witness. Such lessons offer reflections on and applications for human “re-pacing” from constant action and our capacity for overworking, to season-informed and survival-enhancing behaviors, such as embracing measured engagement in work and regular periods of rest. Springing into Action I love spring. I am absolutely fascinated by the emergence of spring flowers and the annual budding of deciduous trees. Each spring, I eagerly look forward to those first few weeks of the season when I take a weekly walk along the same path in my neighborhood to mark the rapid changes in the flowers present and the new leaves emerging on deciduous trees. This year, in particular, in the wake of the coronavirus pandemic sweeping the globe, my walks were quieter, on nearly deserted sidewalks and streets. Yet this year, as always, spring found trees prepared to make

Illustrations by Stephanie Freese

how its seasonal progressions might have annually marked time for these enslaved people. As I rested my hand on its substantial trunk, I pondered that not only had this oak shared the same time and place with our enslaved ancestors, but their exhalations in moments of weariness, bleakness, and even times of hope for better had directly supported its growth. This tree held their essence, bore witness to their lives, symbolized their tenacity, and lived on physically supported by the wood comprising a portion of its trunk, holding their transformed breaths. The McLeod Oak and other centuries-old trees stand as living witnesses to history as they persist on timescales much longer than human life.




© 2015 Audra L. Gibson

At the McLeod Plantation on James Island, South Carolina, the small quarters that were for the enslaved people stand near a large Southern live oak tree, the McLeod Oak (see page 38), purported to be 600 years old. The tree lived alongside these enslaved people, bearing witness to their lives. The carbon dioxide from their exhalations in times of weariness, bleakness, or hope for better supported the tree’s growth.

a withdrawal from the bank of sugars carefully stored as starches in their roots. These plants anticipate spring as the time when these stores must be used to power their budburst and the subsequent emergence and growth of

“In spring, trees make a withdrawal from the bank of sugars carefully stored as starches in their roots.” new leaves. The arrival of new leaves is stimulated by the warmth and sometimes the extended period of sunlight that reliably marks the season. (See “Spring Budburst in a Changing Climate,” March–April 2016.) This process has become a major focus of my studies. My research group has been exploring the light cues that plants use to perceive consistent changes in day length that shift with the seasons. Light cues also link to the processes of leaf development and greening that occur in spring. I have spent more than two decades studying phytochromes, which are light-sensitive proteins that serve many purposes in plants, including the critical need to monitor and respond to photoperiod, the length of time that 40

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a plant is exposed to light. Phytochromes measure hours of daylight versus darkness of night and confer photoperiod-dependent control over responses such as flowering and seed set. These proteins thus sense seasonal progression and accurately coordinate expression of key genes needed to match plant behaviors to a particular season. In spring, therefore, phytochromes coordinate gene expression associated with the production and growth of new leaves and flowers. Southern red oak trees’ newly emerged leaves, like those of many other trees, are vibrantly red in early spring. In my aforementioned studies with Q. falcata, I marveled at this early period of robust red pigment production in seedlings. These bright red pigments, called anthocyanins, may serve as sunscreen for the young leaves before they mature to the point of producing light-screening waxes and other compounds. These anthocyanins protect the leaves from absorbing too much light, which could result in damage during active development of the organelles that carry out photosynthesis. Failure to protect these important structures could lead to the plant overshooting how much light it needs to absorb for robust photosynthesis. In the absence of these red pigments, the leaves would suffer the equivalent of sunburn. Anthocyanins serve vital transient roles until other compounds protect maturing leaves. In addition, the anthocyanin pigments may deter herbivory by insects that are not as attracted to the color red as I am. The new spring leaves result in plants entering a period of marked activity. Leaves are

like solar panels that harvest light for energy production. The harvested light energy, together with the uptake of animal- and humanexhaled carbon dioxide (CO2), drives the production of sugars through photosynthesis, and the subsequent release of the byproduct, oxygen. This byproduct is essential for the animals and humans sharing the habitat with plants and, indeed, forms a return gift in a process of reciprocity for the CO2 that plants receive. Shortly after early spring, the McLeod Oak begins to flower, as do Southern red oaks (right) and other deciduous trees, although the process of continued flower development and maturation marks a transition to summer. The transition from red to green for young oak leaves is a vibrant seasonal marker of time as summer approaches. Since I began to study this process, I’ve frequently been reminded to reflect on the needed preparations for the shift of pace that lies ahead, when I transition from the end of an academic year in spring to different focal points for summer. Summer of Productivity Standing under the massive McLeod Oak last winter, I could vividly imagine the wide span of shade it must cast when fully adorned with its complete, mature summer foliage. Summer is a season when live oaks and deciduous trees such as Southern red oaks bear mature leaves. Because this phase does not encompass the mass emergence of new leaves, as is typical of spring, or the bulk loss of leaves for deciduous trees in fall, summer appeared to me when I was young to be a time when trees were just sitting there. As I began to learn more about plants, I learned summer was a time of intense, if hidden, activity. Apart from the generous offering of shade, a tree’s busy summer life can be completely underestimated. Summer is when the broad and abundant green leaves are focused on energy production through photosynthesis. Energy produced by leaves is used for processes that peak during summer, such as the production of new branches, the maintenance of other nonphotosynthesizing plant parts, and the important transition to reproduction. The reproductive phase is marked by the maturation of flowers, floral pollination, and the production of seeds that bear the next generation. Once these critical plant activities are taken care of, any excess energy can be stored in roots as starch or used for cellulose production. These latter processes restore energy banks that had been drawn upon in early spring, and they ultimately add to the wood of the tree, which represents a form of stockpiling “surplus” during a productive period, as well as storing the breath of animals and humans that contributed to the sugar-producing process of photosynthesis. In good environmental www.americanscientist.org

Courtesy of Melody Rose

In early spring, the leaves of Southern red oak trees (Quercus falcata) are often red. Bright red pigments called anthocyanins serve as sunscreen for the young leaves until they are mature enough to produce light-screening waxes and other compounds. The long, dangling inflorescences also emerge in spring.

conditions that support higher levels or prolonged seasons of photosynthesis and growth, the surplus stored in wood results in wider tree rings than those produced in poor conditions. My enslaved ancestors’ presence, thus,

“In summer, oak trees are busy as their mature leaves vigorously produce sugars and as they prepare for later seasons by storing surplus resources.” was “remembered” through the production of wood in this manner. While I’m conducting research as a creative pursuit and my chosen profession, summer is likewise a busy period for me. During this period, we often expand the number of researchers engaged in our work as we host visiting summer students and are fully engaged in our research without simultaneously being involved in courses. The long days of summer are a period when the phytochromes that we study signal to plants the abundance of light for photosynthesis and energy production. Likewise, we frequently spend long days in the laboratory conducting experiments on plant responses to light to take full advantage of a time 2021



uninterrupted by other school-year demands. We thus devote an abundance of energy to our research questions in summer. Our work is bolstered by the energy and enthusiasm of new researchers, as well as by the foundational knowledge and long-term vision of more experienced team members. Similarly, oak trees are robustly busy as the mature annual leaves vigorously produce sugars and as they prepare for later seasons by storing surplus resources. As summer nears its end, as is characteristic for a deciduous tree, Southern red oaks begin to transition to more maintenance and preparation for a drop in activity as they perceive changes in seasonal cues that mark the arrival of fall. Falling Toward a State of Rest I enjoy fall as an adult, but that was not always the case. I remember fall more for the exhausting labor of raking leaves when I was a child than for the explosion of colors for

“Fall is a time for reprioritizing energy allocations to those activities and behaviors that will ensure restorative rest and maintenance.”

In good summer seasons that support high levels of photosynthesis for long periods, surplus carbohydrates are stored in the wood of Southern red oaks, resulting in wider tree rings than those produced in poorer years.


which I’ve come to eagerly anticipate the season. Fall is a flamboyantly colorful time—or at least ends as one. The cooler temperatures that emerge during fall, as well as a shortening day length, signal a time for plants to actively prepare for rest. As a child, I never truly considered the meaning behind trees losing their leaves in fall. Only as I began to study biology as an undergraduate and to understand that inherited behaviors generally provide a benefit to organisms did I start to ask questions about plant behaviors associated with fall colors. The shorter days indicate reduced availability of light to drive photosynthesis. Additionally, cooler temperatures can have marked effects on enzymatic activity, which can also result in overall reduced metabolism. Together, these fall-associated physiological responses lead to molecular processes that plants need to reduce their energy burdens and actively initiate preparations to maintain essential functions through the pending winter. Plants accomplish this trans i t i o n t o w a rd a more restful period by many

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Alexey Borodin/Alamy Stock Photo

different means, the most obvious of which for some plants is dropping their leaves—the hallmark trait of deciduous plants. The shedding of leaves relieves the plant of a significant energy load, when maintaining these organs is no longer beneficial, because they are no longer active energy contributors. Perennial plants instead put the limited energy produced in late fall into processes related to maintaining critical functions and key organs, such as buds and meristematic tissues— a type of tissue at the growing ends of stems and twigs that consists of undifferentiated stem cells, which can be stimulated to form distinct plant parts. Buds and meristems drive the formation of new tissues and organs throughout a plant’s life cycle during times when they are actively needed and can be supported. Thus, fall is a time for reprioritizing energy allocations to those activities and behaviors that will ensure restorative rest and maintenance. The shedding of leaves is not a haphazard or panic-based process on the part of plants, as the approach of winter is for me every year. Trees such as Southern red oaks drop their leaves in an orderly series of events by which they actively work to recover any nutrients that they can by recycling compounds such as green chlorophyll, the pigment for photosynthesis. I was fascinated the first time I learned that this recycling process is the key action that leads to fall colors, when leaves appear to turn yellow, orange, or red. These vibrant hues are indeed due to the colorful carotenoid and anthocyanin pigments that were synthesized in spring or throughout the life cycle of the trees and that become apparent as the plants’ pools of green chlorophyll decline. (See “Why Leaves Turn Red,” November–December 2002.) We and other scientists have studied the finely orchestrated processes by which light-sensitive proteins perceive changes in day length to signal either the synthesis of chlorophylls, carotenoids, and anthocyanins in spring, or chlorophyll degradation in the shorter days in fall. Due to reduction in daylight hours, the phytochromes perceive the seasonal shift and coordinate expression of genes, including those producing the proteins that break down chlorophylls and promote senescence, or the aging and dropping, of leaves. This translation of seasonal cues to appropriate behaviors is one that always reminds me to prioritize staying in tune with my environment, such as preparing to adjust my activities and sleep during the shift to daylight savings time rather than powering through the change unacknowledged. The leaves’ falling, sometimes gracefully and always noticeably, marks the end of the autumn season. As the temperatures continue to decrease as winter approaches, plants

timescale of carbon storage reproduction decades



plant uses carbon to make sugar molecules

spring growth

plant produces oxygen

animal takes in oxygen wood rays

plant takes in CO2 animal releases CO2

animal breaks down sugar molecules

New spring leaves result in plants entering a period of marked activity. Leaves are like solar panels that harvest light for energy production. The harvested light energy, together with the uptake of animal- and human-exhaled carbon dioxide, drives the production of sugars through photosynthesis, and the subsequent release of the byproduct, oxygen. This byproduct is essential for the animals and humans sharing the habitat with plants and, indeed, forms a return gift in a process of reciprocity for the CO2 that plants receive.

proceed to hunker down for a period during which they largely cease activity and focus on maintenance or rest—a period of pause. Winter as a Time of Pause After many years of living in Michigan, I’ve learned to tolerate, if not enjoy, winter. For plants, the cold days and shortened daily periods of sunlight that typify winter offer limited opportunity for robust photosynthesis that would provide rich sources of energy for plant activity. Thus, plants—especially those that have sacrificed their leaves—have slower metabolism and diminished activity in winter. It is a time of planned pause by these organisms. Standing with the oak at the McLeod plantation, I wondered how my enslaved ancestors must have also used the annual dropping of the resident tree’s leaves in the midst of winter, as is typical for live oaks, as a seasonal www.americanscientist.org

sign that a slower period may have been upon them as well, due to the shorter hours of work with limited daylight hours. During winter, when temperatures reach the freezing point, deciduous trees cease active water flow to avoid ice formation in the vascular tissues, which make up the channels that conduct water. Because water expands as it freezes, the formation of ice in these important tissues could lead to permanent cellular damage that would impede the plants’ ability to recover from winter and resume capillary flow of water in spring. Winterized cells enter quiescence or dormancy and require little energy for maintenance; thus, the excess amount of sugars that results from the focused productivity of summer leaves is stored safely as starch in roots. Alternatively, these sugars may be dissolved in the cytoplasm of some cells and serve as 2021






plant total nonstructural carbohydrates (kilograms)


remobilization and transport during spring


utilization during winter

te ra yd h o rb ca tion l a ra ul tu uc ccum r t ns a

3 no



1 0 Jan












time of year Carbohydrates produced during photosynthesis are stored as starch during the spring and summer, powering the development of new leaves and other plant parts and, later, winter survival. During winter, these stores are tapped to maintain respiration and resist frost damage. In spring, leftover starch stores are remobilized for budburst. This carbon storage and remobilization strategy, used by deciduous trees and many perennial plants, shows a natural seasonal cycle that anticipates and responds to times of high and low resource availability and energy needs.

antifreeze, which lowers the freezing temperature and protects cells from ice formation and the associated damage. Shutting down activity in these ways— ceasing water conductance or using dissolved sugars as antifreeze—represents extremes that serve plants well in winter: freeze avoidance or freeze tolerance, respectively. Plants such as deciduous trees may use a combination of these approaches to overwinter robustly.

“It is all too common that we humans perennially persist in a state of all-out action, as if we exist in a perpetual state of summer.” The short, overcast, and sometimes brutally cold days of winter trigger a change of pace for me, if not focus. In keeping with the style of modern society, our research continues full speed ahead because of the use of lighted growth cabinets and temperature-controlled greenhouse spaces. As much as I enjoy long walks, winter is not a time when I am drawn to linger outside. Fascinated by the leafless deciduous trees or the stalwart evergreens as they withstand the cold that I can bear only for brief moments, I often take drives and reflect on how these plants persist in winter, largely at rest. The plants’ overwintering inspires me to slow down as fully as possible in the winter break between academic terms, and to rest and restore before emerging anew in the next academic season. 44

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Seasonal Adjustments Like plants, humans also have seasonal shifts—whether these are based on environmental seasons or other seasons related to development, such as life stage. I suffer from seasonal allergies, so I can certainly attest to being subject to the environmentally tuned shifts that organisms undergo, such as many plants’ mass release of spring pollen. Whereas some of our seasonal shifts may occur over years, rather than over the span of a calendar year, we know that seasons of maturation and growth in humans also can require periods of focused productivity supported by significant energy inputs. Certainly, parents like me who have been responsible for the energy input of rapidly growing boys will attest to this fact. Yet, despite our recognition of the environmental and developmental seasons that affect our energy requirements, the common human condition is to pursue constant action with limited attention to seasonal adjustments. Humans, unlike plants, sometimes overlook the need for adequately anticipating when action needs to be tuned to season-like cues. The enslaved people of McLeod had no choice but to be attuned to the cycles of the seasons and the plants. Today, we have choice—but along with that liberation, we’ve lost a valuable connection. Accurately assessing when we are most supported—akin to the anticipation and early action of spring and high productivity of summer—is critically important. It is equally essential that we anticipate and appropriately respond to periods that require us to prepare for and engage in planned rest and pause.

Although it is always critical for us to pay attention to the demands of life, even as we navigate educational or professional commitments, the recent coronavirus pandemic has amplified this need for many of us, as well as for those we mentor or lead. It was clear to me that I and members of my research team were each navigating the potential health risks differently. Additionally, the potential mental and emotional stresses of navigating a world in the midst of a pandemic had different consequences depending on whether we were near or far from family and loved ones. All these realities, which existed before and will persist after this moment, affect our abilities to be present for and engage in our research responsibilities. The importance of trying to anticipate a need for a shift in focus, equivalent to a state of rest, was high on my list as a mentor and leader. In the case of the pandemic, distinct from many other times, all but essential workers were forced into a state of pause in some regard, even as many of us attempted to keep working or learning from home. Indeed, it is all too common that we humans simply perennially persist in a state of all-out action, as if we exist in a perpetual state of summer, with access to all the resources we may need for full productivity. The COVID-19 pandemic has been an extreme kind of forced pause, but most people have reacted by trying to work as aggressively as ever. In our quest for a “new normal,” we may not be adequately adjusting to the disruption that this crisis represents. What if we used this moment to pay more attention to the natural cycles that used to force life to slow down for part of the year, every year? When we engage in continuous action despite the fact that all cues point to a time for rest or pause, we can end up in a compromised state in which our physical, mental, or emotional capacities—the equivalent of our root-based energy stores—are depleted and we enter “enforced,” rather than carefully planned and orchestrated, pause. This forced pause can come from physical exhaustion or illnesses, chronic insomnia, or mental or emotional burnout, among other causes that prompt us to pause and rebalance physically, mentally, or emotionally. The Gift of Plant Wisdom During my annual spring walks to admire the brilliant red leaves that emerge post-budburst, I’m reminded to stop and reflect on how I am actively anticipating or preparing for my pending seasons—personal and professional. I’m also prompted to ask whether I’ve had an appropriate period of rest like the plants have as they emerge from winter into spring. Likewise, as I eagerly anticipate the fall colors of deciduous plants annually, I have learned to take their cue to remind myself to prepare for a “quieter” existence and to conserve energy as I may be www.americanscientist.org

heading into a period of planned pause. Just as deciduous plants release leaves that would be too expensive to bear through winter, my quieter existence often consists of periods such as quarterly retreats with limited formal responsibilities, allowing me to focus on restoring and preparing for a busier period of planned commitments and responsibilities ahead. As I write this, many people across the globe are in, or perhaps in some cases are emerging from, an enforced pause associated with the global coronavirus pandemic. Each time I am forced into pause by external factors or occurrences, I recommit to intentionally approach future pauses from a state of anticipation, focused productivity, and proactive planning, as well as preparation for rest. I’m reminded in these periods of my enslaved ancestors, and indeed all our ancestors whose lives were dictated by natural environmental seasons. This seasonally driven lifestyle included cycles of intense activity and periods of slowed pace and rest. Although we fight against it in our current lives of constant busyness, our bodies remember a need for season-driven behavioral adjustments. To thrive optimally, we need to honor these natural cycles. I’ve come to depend on plants as dedicated and persistent teachers for inspiration and guidance in these efforts. Deciduous trees bear strong witness to the wisdom of seasonal living and being, and they stand prepared to teach us these lessons every year—if only we can learn these lessons well and, better yet, aptly implement them. Bibliography Choinski, J. S., Jr., and R. R. Wise. 1999. Leaf growth development in relation to gas exchange in Quercus marilandica Muenchh. Journal of Plant Physiology 154:302–309. Fadón, E., E. Fernandez, H. Behn, and E. Luedeling. 2020. A conceptual framework for winter dormancy in deciduous trees. Agronomy 10(2):241. Karageorgou, P., and Y. Manetas. 2006. The importance of being red when young: Anthocyanins and the protection of young leaves of Quercus coccifera from insect herbivory and excess light. Tree Physiology 26:613–621. Montgomery, B. L. 2016. Spatiotemporal phytochrome signaling during photomorphogenesis: From physiology to molecular mechanisms and back. Frontiers in Plant Science 7:480. Montgomery, B. L., et al. 2001. Biliverdin reductaseinduced phytochrome chromophore deficiency in transgenic tobacco. Plant Physiology 125(1): 266–277. Primka, E. J., and W. K. Smith. 2019. Synchrony in fall leaf drop: Chlorophyll degradation, color change, and abscission layer formation in three temperate deciduous tree species. American Journal of Botany 106:377–388. Wisniewski, M., C. Bassett, and L. V. Gusta. 2003. An overview of cold hardiness in woody plants: Seeing the forest through the trees. HortScience 38:952–959. Beronda L. Montgomery is a professor and administrator at Michigan State University. She received her doctorate in plant biology from the University of California, Davis. She is author of the forthcoming Lessons from Plants (Harvard University Press). Twitter: @BerondaM. Website: http:// www.berondamontgomery.com 2021



Dangers of Divided Attention Multitasking may seem to be a time-saver, but the working memory can only handle one task at a time, so attempts to divide concentration inevitably backfire. Stefan Van der Stigchel


rian Cullinan, an accountant at the prestigious PricewaterhouseCoopers firm, considered himself luckier than most in his job. After all, he was responsible for handing out the prizes at the annual Academy Awards ceremony. He and his colleague, Martha Ruiz, were tasked with ensuring that the votes were counted correctly, that the envelopes containing the winners’ names were in order, and that the right envelopes were handed to the right people at the presentation. They always made two sets of envelopes, one for Cullinan and one for Ruiz, who stood on opposite sides of the stage so they could hand the correct envelope to the presenters just before they came on stage, regardless of which side they chose to make their entrance. All that either Cullinan or Ruiz had to do was to make sure they disposed of their copy of the envelope when the other copy had been handed over on the opposite side of the stage. What could possibly go wrong? The 2017 Academy Awards provided one of the most embarrassing moments in the ceremony’s long history. Ruiz had just handed the envelope with the winner of the Best Actress award, Emma Stone for the movie La La Land, to presenter Leonardo DiCaprio. The next prize was the last and most important of the night: Best Picture. However, Cullinan handed the wrong envelope to the presenters, Warren Beatty and Faye Dunaway. He had forgotten to dispose of the envelope for the previous Best Actress award and mistakenly handed it to Beatty.

By the time the mistake was discovered, the producers of La La Land were already busy giving their acceptance speech. Ruiz and Cullinan had to walk onto the stage to sort out the mess, after which the audience was informed of the error and the Oscar was presented to the winning movie, Moonlight. How could something like this happen? There is no shortage of theories, of course, but one fact in particular stands out. Cullinan is a fervent Twitter user, and on the evening in question he posted a photo of Emma Stone backstage with her award. He later deleted that tweet, but not before people realized that he had posted it just after Emma Stone had walked offstage with her award—the exact moment when Cullinan should have been disposing of the envelope for Best Actress and getting the next one ready. The job with which Cullinan was tasked may not seem very difficult, but neither is it one that can be carried out on autopilot. Taking care of the envelopes requires the use of the working memory, and when this task is combined with another task (such as writing a tweet), the working memory must carry out two tasks simultaneously. Therein lies the problem: Our brain is not capable of taking on two tasks at the same time when both require the use of the working memory. If you believe you are able to do several things at once without any difficulty, you are likely the victim of the illusion of multitasking. What happens is that you switch so quickly between two tasks that it appears as if you are doing them simultaneously. However,

you can observe in the brain that the two halves charged with executing the tasks become alternately—not simultaneously—active, meaning that the brain has to switch continuously between the two activities. Multitasking can therefore be more accurately described as switching between tasks as opposed to combining them. But is switching between tasks easy? Is it possible to do so without any negative effects? Would Cullinan have made the same mistake if he hadn’t grabbed his phone to take a photo of Emma Stone and share it with the world? To answer these questions, we need to look at the experiments that have been carried out on task switching. Studying task switching tells us an awful lot about how flexibly our brain is able to interact with the world around us. We are constantly being asked to do multiple activities, depending on the situation, such as search for our wallet so that we can then find our commuter pass before looking for the right platform and making sure we don’t bump into other people while running to catch our train. In the lab, this switching is studied using more abstract tasks, but the principle remains the same. One example is the number-letter task, in which test subjects are asked to switch between categorizing numbers and letters. Before each task they are shown the word number or letter, after which a number–letter combination appears on a screen (for example, 2B or N3). When the task is related to numbers, the test subjects have to say as quickly as possible whether the

QUICK TAKE Quickly switching between tasks creates the illusion of multitasking, but this style of work ends up taking longer and creating more errors than concentrating on a single task.


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Task switching at work is most often caused by interruptions, either by coworkers or by various media. Often people stop working and check for messages out of habit.

Students who chat online while studying or in lectures absorb less information, take fewer notes, and have lower scores on tests than those who are not distracted.

What are you working on? How is your work project going?

When will you be finished?

Social Media

Illustrations by Tom Dunne

• email • twitter

Most office workers find themselves distracted throughout the day by interruptions from coworkers, competing priorities, and the addictive pull of social media. As more people work from home because of social distancing guidelines, the additional distractions of household chores and family care have divided their attention further. Attempts to juggle these tasks often lead to stress, frustration, and errors.

number they see is odd or even. For the letter task they must say whether the letter is a vowel or a consonant. Sometimes they have to switch between the two tasks, and sometimes one of the tasks is repeated. On average, test subjects are slower to react to a number-letter combination when they have to switch between two tasks than when the task is repeated. There are always costs attached (in terms of reaction time and the number of mistakes) to switching between tasks that require the use of the working memory. It takes longer to complete each task (or switch costs), and the test subjects will make more mistakes than when their attention is focused on a single task. All tasks that require your attention and thus cannot be carried out automatically will draw on your working memory. The extent to which they do so depends on the level of difficulty: The costs are higher when carrying out a complicated task than when the task www.americanscientist.org

is less difficult but still requires working memory. After all, it takes more time to tidy a messy room than one that is relatively clean. This analogy also explains why the switch costs are lower when test subjects know in advance which task they will have to carry out after the switch. It allows them to clear their working memory and prepare for the next task before it comes along. It also suggests why interruptions from outside are often more of a hindrance than when you make the switch yourself. When your work is interrupted, you do not have the opportunity to empty your working memory completely, so a remnant of your attention remains behind in the previous task. The larger the remnant that you carry over into your next task, the higher the switch costs will be. Interestingly, despite the myth that women are better at multitasking than men, these studies never show differences between men and women in

their ability to switch between tasks. However, it has been established that some people are better than others at switching between tasks. It simply costs them less time and effort, regardless of their gender. Media Usage and Multitasking We all know them (indeed, you might be one of them yourself): those people who are always checking their email and social media when they should be studying or concentrating on their work. Ninety-five percent of us spend an average of one-third of the day simultaneously keeping tabs on various (social) media—for example, checking Facebook on your phone while watching TV and keeping an eye on Twitter on your tablet at the same time. A 2009 study led by Eyal Ophir, then a symbolic systems researcher at Stanford University, discovered that people who spend a lot of their time on various media have higher switch costs than people who have a lower level of media usage. The level of multimedia usage is one of the factors that predict how efficiently the brain is able to switch between tasks. Switching tasks was not the only area where heavy media users registered a poorer score. 2021



Matt Sayles/Invision/AP Images

At the 2017 Academy Awards ceremony, PricewaterhouseCoopers accountant Brian Cullinan divided his attention between handing out award envelopes and posting to social media (left). This failed attempt to multitask resulted in Cullinan handing the wrong envelope to presenters Warren Beatty and Faye Dunaway, who mistakenly announced La La Land as the Best Picture winner. After officials corrected the error, La La Land producer Jordan Horowitz held up the card from the correct envelope, which indicated that Moonlight had won Best Picture (right).

They were also more easily distracted by incoming information and performed worse at memory tasks. Although multitasking is clearly not good for concentration, research

such as the notifications you receive on your smartphone or the mere presence of your tablet next to you, will command your attention and distract you from whatever it is you are doing. This

Our brain is not capable of taking on two tasks at the same time when both require the use of the working memory. on heavy multitaskers indicates that multimedia usage has no permanent effect on the brain. Instead, it may be the other way around—people who are more easily distracted may be more inclined to use multiple media simultaneously. The more you think about this explanation, the more likely it seems. If you find it difficult to ignore distractions, you will automatically be more inclined to multitask. The stimuli with which you are constantly bombarded, 48

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increased opportunity for multitasking can form a significant challenge for people with less efficient brains. Multitasking on the Work Floor How often do you find at work that you are doing several things at the same time? According to research, most of us are guilty of multitasking at work. It depends, of course, on what kind of work you do, but very precise results have been produced for certain professions, particularly those

Chris Pizzello/Invision/AP Images

that involve working in shared office spaces. In such situations, the chance of you becoming distracted from your work is far greater than when you have an office to yourself. It turns out that task switching at work is often the result of interruptions by others. In a 2005 paper, Gloria Mark, Victor M. Gonzalez, and Justin Harris—all at the Donald Bren School of Information and Computer Science at the University of California, Irvine—described an observational study they conducted of office workers. They used a stopwatch and a notepad to track the behavior and activities of employees over the course of their working day. The employees in question were all working on different projects simultaneously, meaning that they often had to do several things at once. The study revealed (after an observation period of 700 working hours) that on average, the workers were interrupted every 11 minutes and the interruption usually caused them to shift their attention to a different task. The interruptions included answering the telephone, questions from colleagues, and incoming email. When the interruption was not directly related to whatever they were originally doing, it took another 25 minutes before they returned to that task. Another reason for switching between tasks is a lack of concentration.


mean reaction time (milliseconds)

alternating-task blocks repetitive-task blocks 8,000



2,000 low


rule complexity mean reaction time (milliseconds)

Many workers find it difficult to work on one task for a significant period of time and often end up making a phone call or checking their email after only 10 minutes have elapsed. A 2011 paper conducted by sociologists Judy Wajcman and Emily Rose, both of the London School of Economics, examined employee work habits at an Australian telecommunications firm. Their study revealed that most of the participants spent less than 10 minutes working without interruption on a single task and that the average was as low as three minutes. Much of the task switching was not the result of outside interference. Indeed, 65 of the 86 switches reported were initiated by the employees themselves. In the majority of cases, the employee was simply checking to see whether they had received any new messages, even though they had not received any notification of such. All out of sheer habit really—you could even call it an addiction. Just a quick check to see if there’s anything new in the inbox. When something new arrived in the employee’s inbox, the employee was usually inclined to respond immediately, especially to messages received on their cell phone. Replying to the incoming message also caused employees to open other communication channels or media, as if they were taking a short break from work, one they wouldn’t have taken if they had not received the message in the first place. After you have been interrupted it takes a little time before you can recall exactly what it was you were doing and free up your working memory for the task again. Switching regularly between tasks can result in your work becoming super ficial because you never get down to the nitty-gritty of whatever it is you are working on. Think, for example, of managers who insist that their staff respond immediately to all incoming messages, or companies where employees are required to keep a chat screen open on their computers and are praised for their speed and commitment to the cause when their reaction times are quicker than others. You could ask yourself whether these are the kinds of workers who make the all-important major breakthroughs and contribute most to the firm. After all, we know that many important discoveries have been and are still made in the solitude of an attic, a place that

alternating-task blocks repetitive-task blocks 6,000


2,000 present


task cuing Multitasking requires people to rapidly switch their attention, and each transition takes time. Test subjects reacted most quickly when switching between easy, repetitive tasks, but took much longer when the tasks were varied and complex (top). A “cue” that a task switch was on the horizon helped test subjects react more quickly than when the new task was a surprise (bottom). (Adapted from J. S. Rubinstein et al., 2001.)

we often associate with the minimum level of distraction and the highest levels of concentration. Regular interruptions can cause workers to work in a hasty and less efficient manner. A 2008 study led by Mark confirmed that task switching led to increased stress. Furthermore, constantly switching between tasks doesn’t do the atmosphere on the work floor any good. How do you feel when you have had to put up with interruptions all day at work? The long-term presence of stress hormones in the system often results in crippling fatigue, so don’t be surprised if you feel completely exhausted after a day of stopping and starting and stopping again. Multitasking and Learning Our brain is designed to learn, even well into old age. Every action that is performed correctly results in a strengthening of the pathways between the neurons involved in carrying out that action. Conversely, pathways that

are left unused become weaker over time. This process helps make our brain more efficient at tasks that are carried out on a regular basis. To learn, you have to focus your attention fully on the subject at hand. You can still learn while multitasking, but you will not be able to use the information as effectively at a later moment, which makes the benefits of learning in this way very shortlived. In fact, you use different parts of the brain when learning during multitasking than when you focus on one single task. In a 2006 study, Karin Foerde and her colleagues at the University of California, Los Angeles, Brain Research Institute gave test subjects several sets of cards. The participants then had to learn different rules for each set of cards. For some of the sets they learned the rules without any distractions, but for other sets they were also required to listen to high- and low-pitched tones on headphones and remember how many times they heard a high tone. 2021



baseline (no interruption)

mental workload







time pressure


What is the result of your project?

same context (interruption)






Is it going to rain on Tuesday?

different context (interruption)






In addition to derailing productivity, interruptions can increase anxiety. Test subjects who were interrupted about matters related to their work became more stressed and frustrated, and they experienced a greater sense of time pressure. When the interruption was about matters unrelated to their work, their mental workload and effort increased as they attempted to juggle competing priorities. (Adapted from G. Mark et al., 2008.)

Although this distraction did not have a negative effect on the test subjects when it came to learning the rules, it did make it more challenging for them to recall those rules. When they were asked to work with the same sets in a subsequent session, they found it difficult to remember the rules they had learned while listening to the tones.

tion was not retained and could not be retrieved later. If, as Foerde’s study indicates, multitasking has a negative effect on our ability to learn, then this finding has major implications for how we educate our children. If the attention of students is constantly switching from one task to another, their education is

Undistracted students wrote 62 percent more information in their notes than the distracted groups did, and their notes were far more detailed. Using an MRI scanner, the researchers could see which areas of the brain became active when the test subjects were engaged in learning. When they were not subject to any distractions, the hippocampus became active. This part of the brain plays a crucial role in processing, retaining, and retrieving information from long-term memory. When they were learning while listening to the different tones (that is, while multitasking), the hippocampus was much less active or not active at all, meaning that the new informa50


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bound to suffer. Observational studies have shown that students spend very little time concentrating on a single task without interruption when they are studying at home. Even when they were told that they had to study a very important piece of text, they were unable to concentrate for more than three to five minutes on that task. Not surprisingly, social media and chat messages were identified as the main distractors. There was also a strong correlation between the use of social media while studying and perfor-

mance at school: the heavier the usage, the poorer the performance. Multitasking and Studying Unfortunately, not everything in life is as gripping as your favorite Netflix series. Students find it particularly difficult to concentrate for any length of time when the material they are studying is dull and complex. This difficulty is exacerbated by the presence of smartphones and social media in classrooms and lecture halls. Terry Judd, who studies medical education at the University of Melbourne, analyzed 3,372 computer sessions by 1,249 students who had been instructed to study on their own without any interference from others. Almost all of the sessions (99 percent) betrayed the telltale signs of multitasking. Although the bulk of the students’ time was spent studying, Facebook was responsible for a significant 9.2 percent of their time, with 44 percent of all sessions showing log-ins to Facebook. Those students who opened Facebook were also the ones who spent less time working on a single task without interruption and who were most inclined to switch between tasks. But does the presence of social media lead to poorer results? Let’s take a look at a study carried out in 2007 by Laura E. Levine and her colleagues at the Central Connecticut State University psychology department that examined the effect of chatting on students’ concentration levels when doing homework. The researchers expected that due to the growing popularity of online chatting, the students

Maximizing Concentration While Working from Home


ocial distancing practices because of the coronavirus disease 2019 (COVID-19) pandemic have led many businesses to close their offices and transition employees to working from home. This change can be a boon, as studies have shown that working conditions in home offices are more conducive to concentration and productivity than those in an open-plan office. However, to realize those benefits, workers need to strategically alter their home environment and mindset. I will provide some tips and tricks for working efficiently from home. A common pitfall when working from home is that work and personal lives become intertwined. Perhaps the kitchen table is also your workplace, or you are looking at your children’s mess during a video call. Even if you are working from home, it is good to literally close your office door behind you. If you do not have the space to set up a separate office, do your best to make your workplace distinct from the place where you unwind. Try not to work in the same spot where you have your meals, but if you must set up your home office at the kitchen table, dismantle your workplace and clear away your materials to signal the end of the working day. It is best to divide the day into blocks in which you combine similar tasks. For example, you can create blocks for video meetings, phone calls and emails, and working on bigger projects. If you create a fixed daily schedule in which you make time for each task, you can put the other tasks out of your mind when it is not their turn for your attention. There is no gold standard concerning which block is best to schedule at the beginning or end of your workday. Whereas one may prefer to start with the smaller tasks, others may prefer to start the day with two hours of focused work on a big assignment. Tasks that don’t require much attention are best saved for when you are least productive. Most people have a dip in concentration after their lunch break, so that is a great opportunity for boring or annoying tasks. The most complex tasks are best performed when you have a lot of energy. Working from home offers the possibility of following your ideal rhythm more easily. Do you like working in


the morning, or do you prefer the evening? Working from home can provide this flexibility, as long as your work and personal lives do not get mixed up. Don’t give in to the urge to tidy up the dishes while you are working, and do not send an email to your colleague when you’re still having breakfast. While working from home, you want to be easily accessible to colleagues. But ask yourself: Is it really necessary to

machine, or to meet with colleagues. Make a concerted effort to move during the day. Have your conference call while walking, go for a bike ride during your break, or alternate sitting and standing during your workday. In-person meetings can be vital for developing new ideas. Colleagues who brainstorm in the same room can pick up on subtle body movements, make eye contact, respond quickly to

make a separate workspace

clean up work stuff daily

focus on one task at a time 9:30 – 10:30 chatting with colleagues 1:30 – 2:30 phone calls and emails make eye contact in meetings

• • •

• • ••

• • • •

create blocks do not mix up personal and work tasks

leave all communication programs open all day? To prevent getting bombarded with messages and notifications, make precise arrangements with colleagues. Agree on which channels you use to communicate collectively, and do not use more than two different programs. If you want to regularly turn off all workrelated notifications with confidence, make sure you first establish agreements about your accessibility. These guidelines make it clear to everyone when you can or cannot disturb one another. Those who work from home run the risk of moving a lot less than when they worked in an office. In the morning you no longer walk to the train or take the stairs to the right floor, and you miss the strolls to the copier, to the coffee

10:45 – 11:45 video meetings 3:00 – 4:30 major projects

exercise/ move during the day

one another, and create the right atmosphere. A 2012 study led by Peter A. Gloor of the Massachusetts Institute of Technology Center for Collective Intelligence revealed that the more colleagues saw one another, the more creative their ideas became. Indeed, colleagues who make eye contract trust each other more, and this trust is crucial for creativity. It is precisely those ingredients that you miss in a video call when everybody sits at home. Some organizations are therefore eager to get staff back in the office, even if it is just once a week. Companies could, for instance, convert their open-plan office into a meeting place for work meetings. Perhaps the open-office space could be good for something after all. 2021



What are you working on? How is your work project going?

When will you be finished?

Social Media • email • twitter

would be more inclined to multitask Wood of the psychology department at and, as a result, less able to concentrate Wilfrid Laurier University in Ontario on their studies. The students were invited students to attend three difasked to fill in questionnaires where ferent lectures, after which they were they could indicate how much time asked a number of questions related they spent chatting and how well they to the talks. The students were divided thought they were able to concentrate. into separate groups: a control group The results were crystal clear: Students that had no access to any media and who spent more time chatting online a number of experimental groups while studying found it more difficult that were instructed to use a differto concentrate than the students who ent type of media during the lectures, spent less time chatting. such as email, Facebook, or messagBased on these correlaing on their phones. All of tions, it is tempting to draw Pushing distractions into the background allows people to concentrate the experimental groups the conclusion that online fully on the task at hand. Rejecting multitasking in favor of dedicating made more mistakes in chatting leads to reduced their full attention to one task at a time leads to higher quality of work the subsequent test than powers of concentration and lower stress. the control group. A 2013 while studying. The same study by communications applies to other studies that have that students will increase their media researchers Jeffrey H. Kuznekoff of shown a correlation between the num- usage when their grades turn out to Ohio University and Scott Titsworth of ber of text messages a student sends be poor—a completely different hypo- the Scripps College of Communication during lectures and their final grade, thesis using the very same data. produced the same results, and also as well as between multitasking in There is even a third possibility: revealed that the students who had not general and the average grades of stu- that there is something else behind the been distracted wrote down 62 perdents. The problem with these stud- correlation, such as a person’s mental cent more information in their notes ies is that they are all based on cor- aptitude. There may be a very good than the distracted groups did, and relations and usually follow the same reason someone allows themselves to that their notes were far more detailed. method: Scientists measure the media be easily distracted by different media. usage—using a questionnaire or, for Some people are less able to concen- Multitasking Is Not Necessarily Bad more accurate results, by saving and trate than others and therefore more It is important to note that not all consulting the computer’s history— inclined to be distracted by modern multitasking is harmful. We are not before measuring the test subject’s per- media. One hundred years ago, their always learning or working on someformance on a certain task and com- counterparts may have done the same thing, and it is not the end of the world paring the two sets of results. They by slipping out to kick a ball around when you read the newspaper more establish a negative correlation: the or just sitting and staring into space slowly than usual because you are lisheavier the media usage, the higher for a while as a break from their stud- tening to the radio at the same time. the incidence of multitasking and the ies. You simply cannot claim that poor Furthermore, the presence of a second poorer the performance. grades are caused by heavy media us- source of information does not necHowever, you cannot conclusively age. The most you can say is that poor essarily mean that it will command say that one causes the other; correla- grades and heavy media usage tend to your attention. We are more than cation says nothing about causality. Al- crop up together. pable of ignoring a continuous source though it is tempting to conclude that Experimental studies have also been of information. For example, you can the student’s poor performance is the used to examine things such as the ef- study with the radio on as long as result of intensive media usage, it is not fect of media usage on study perfor- you are able to ignore the information the only conclusion you can reach. You mance (rather than perceived concen- coming from the radio. I remember could also claim the exact opposite: tration). In 2011, a team led by Eileen once having the radio on in my office 52

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when a friend of mine came on the air unexpectedly. At least that’s what I heard afterward, because it completely passed me by at the time. I had been so engrossed in the paper I was writing that I had paid no attention to the radio at all. When people wish to concentrate on something, they often use a trick that

newspaper NRC Handelsblad, a surgeon revealed that he never listened to classical music during an operation because he would be inclined to really listen to it. Therein lies a crucial factor when it comes to explaining why listening to music can be a help when we are working: You are not really listening

Music doesn’t just cause more activity in the brain, it also ensures that you are less easily distracted by unexpected sounds.

multitasking a lot more than we used to. We still haven’t acquired enough hard data, however, and until then we will have to make do with what we know and also keep in mind the limitations of the human brain. The next time you read a dramatic headline about the rise of multitasking, remember that, yes, we are more prone to it than ever before, but that does not mean it is always a problem. Increasing our knowledge about how concentration works can help us choose wisely when we need to perform several tasks at once. If nothing else, it may help prevent backstage accountants from making the same mistake again at next year’s Oscars. Bibliography

at first seems counterintuitive: they put on some music. My parents were never able to figure out how I could do my homework while listening to my favorite Eurodance hits. I have fond memories of listening to DJ Paul, 2 Unlimited, and (my personal favorite) Cappella while cramming for my exams. Today I still study and write with music playing in the background, although I think (and hope) that my musical tastes have become a bit more refined since then. The next time you stroll around town, take a look in the windows of those hip cafés where students and other young people gather to study or work—many of them will be wearing headphones. In a survey carried out in the Netherlands in 2012, 80 percent of respondents said they listened to music every day at work. At first, you might think that the music issuing from all those headphones can lead to nothing but more distraction, to even more stimuli that people then have to try to ignore. However, the majority of workers say that they work better when listening to music. How is that possible? Well, first of all, we cannot maintain a high level of concentration indefinitely. Our concentration tends to falter the longer we try to keep our focus, especially when we are carrying out either very complicated or very boring work. Listening to music can provide the brain with new impulses and thus help keep it alert. Even surgeons listen to music while working—as many as 8 out of every 10, according to a 2010 British survey. Of course, it also depends on what kind of music is playing. In an interview with the Dutch www.americanscientist.org

to the music at all. If the surgeon were to listen to his music intently, it would demand some of his attention and require the use of the working memory. He would then be multitasking, and we all know the consequences of that. It almost goes without saying that you will be able to work a lot more efficiently when you listen to music with which you are already very familiar or to a playlist with mellow music than when you listen to new music or music that demands a lot of your attention. Music doesn’t just cause more arousal; it also ensures that you are less easily distracted by unexpected sounds. Think back to the students in the hip café, a place where the sounds are wide and varied: conversations beginning and ending, people walking in and out the door, the coffee machine grinding and pouring. By wearing headphones, you can block out all these stimuli and listen only to the ones that you have chosen to let in because they are less likely to distract you. And when your concentration begins to falter, you can just stop working for a moment or two and enjoy the music, which helps you build up your concentration again. It would also be tempting to take these findings out of context and predict a gloomy future for our society. But there is no evidence that we have become less intelligent as a result of all the distractions of modern life. On the other hand, multitasking is certainly a problem when you want to be able to concentrate for longer periods of time. The rise of social media is presenting us with ever more opportunities for multitasking, and we are probably

Foerde, K., B. J. Knowlton, and R. A. Poldrack. 2006. Modulation of competing memory systems by distraction. Proceedings of the National Academy of Sciences of the U.S.A. 103:11778–11783. Kuznekoff, J. H., and S. Titsworth. 2013. The impact of mobile phone usage on student learning. Communication Education 62:233–252. Levine, L. E., B. M. Waite, and L. L. Bowman. 2007. Electronic media use, reading, and academic distractibility in college youth. CyberPsychology & Behavior 10:560–566. Mark, G., V. M. Gonzalez, and J. Harris. 2005. No task left behind? Examining the nature of fragmented work. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems. doi: 10.1145/1054972.1055017. Mark, G., D. Gudith, and U. Klocke. 2008. The cost of interrupted work: more speed and stress. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems. doi: 10.1145/1357054.1357072. Ophir, E., C. Nass, and A. D. Wagner. 2009. Cognitive control in media multitaskers. Proceedings of the National Academy of Sciences of the U.S.A. 106:15583–15587. Rubinstein, J. S., D. E. Meyer, and J. E. Evans. 2001. Executive control of cognitive processes in task switching. Journal of Experimental Psychology 27:763–797. Wajcman, J., and E. Rose. 2011. Constant connectivity: rethinking interruptions at work. Organizational Studies 37:941–961. Wood, E., L. Zivcakova, P. Gentile, K. Archer, D. De Pasquale, and A. Nosko. 2011. Examining the impact of off-task multi-tasking with technology on real-time classroom learning. Computers & Education 58:365–374.

Stefan Van der Stigchel is a professor of cognitive psychology at Utrecht University in the Netherlands and principal investigator of the research group AttentionLab. This excerpt is expanded and adapted from his book Concentration: Staying Focused in Times of Distraction, translated by Danny Guinan, copyright 2020 by MIT Press, https://mitpress.mit.edu/books/concentration. Email: [email protected] 2021



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, which explores how science intersects with other areas of knowledge, entertainment, and society: americanscientist.org/blogs /science-culture. ALSO IN THIS ISSUE HOW TO ARGUE WITH A RACIST: What Our Genes Do (and Don’t) Say about Human Difference. By Adam Rutherford. page 57

ONLINE On our Science Culture blog: americanscientist.org/blogs /science-culture Presents of Mind Our 2020 Holiday Gift Guide contains reviews of books for children and adults that will make excellent gifts for your friends and family members any time of year.

From Spiders of the World: A Natural History, edited by Norman I. Platnick.


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Using Data to End Oppression Kaitlin Stack Whitney DATA FEMINISM. Catherine D’Ignazio and Lauren F. Klein. 324 pp. The MIT Press, 2020. $29.95. (The book can be read free of charge online: https://datafeminism.mitpress.mit.edu)


s scientists, we may have an inclination to view data as scientific facts that speak for themselves. But data are the product of many small but cumulative choices we make about what to document and quantify. Those choices are important, because data have the potential to be enormously influential. In Data Feminism, Catherine D’Ignazio and Lauren F. Klein invite us to think deeply about the underlying forces that can subtly shape the presentation and analysis of data, and about the conclusions the data are used to support. They propose that we use feminist thought to guide our approach. The book includes many examples of data science relating to sex and gender, but don’t let the title fool you— the authors’ recommendations apply to all data and all kinds of science. Data feminism is ultimately about power—about who has it and who doesn’t, and how power imbalances can be shifted. Data have power that is often wielded uncritically, without considering whose agenda is being served. Data feminism attempts to correct that, in large part by expanding awareness of implicit biases in the collection and presentation of data. According to the authors, the feminism that informs data science needs to be intersectional— that is, it should consider how additional dimensions of identity, such as race and class, intersect with feminism and with each other. D’Ignazio and Klein are using the term feminism, they say, as a “shorthand” for “projects that

name and challenge . . . forms of oppression [and] seek to create more just, equitable, and livable futures.” Their aim is to examine inequities and use data to make change. Data Feminism is also about and for members of communities that have been minoritized (devalued and disadvantaged by dominant groups); the authors believe strongly that minoritized people and communities need to be involved in decisions about what data should be collected and how those data should be used and presented. D’Ignazio and Klein intentionally use an expansive definition of data, in part to push back against historical gatekeeping in science that has focused on asking “What are ‘real’ data?” and “Who is doing ‘real’ science?” The book is organized into seven chapters, each of which in turn takes up one of seven principles: (1) “examine power” (consider the current configuration of society, in which dominant groups experience unearned advantages and other groups are disadvantaged); (2) “challenge power” (analyze and expose oppression, envision equity); (3) “elevate emotion and embodiment” (remember that visualization is rhetorical and that unemotional visualizations are not neutral); (4) “rethink binaries and hierarchies” (question how things are counted and classified); (5) “embrace pluralism” (include multiple perspectives and the voices of the minoritized at all stages of a data project); (6) “consider context” (remember that numbers derive from a data setting that has been influenced by power differentials); and (7) “make labor visible” (acknowledge to the greatest extent possible the vast network of people who have contributed to a data project). Each chapter demonstrates the importance of its principle and provides examples of organizations or scholars applying the principle in their approach to working with data. The authors’ goal is to explain, and advocate for, a process-based approach. Power can take the form of refusing (or neglecting) to include a particular

group when data are being collected. One way to respond is with counterdata—data that individuals and grassroots organizations collect and analyze themselves in order to combat existing power imbalances. Some of the most interesting examples in the book have to do with counterdata. For example, more than 50 years ago in Detroit, Black residents of neighborhoods alongside a popular commuter route through the city became concerned at the number of their children who were being killed when hit by the cars of commuters. They couldn’t find any data to substantiate what they were seeing, because detailed records of these deaths were not being kept, so they decided to collaborate with white male geographers at nearby universities to produce a heartbreaking map of this vehicular violence, titled “Where Commuters Run Over Black Children on the Pointes-Downtown Track” (1971); the map used black dots on a street grid to show where children had been killed. More recently, the Westside Atlanta Land Trust used participatory data collection to build its own set of data about abandoned properties and property disinvestment and used it to lobby municipal policy makers for affordable housing. Yet the authors make the point that collecting data on minoritized groups isn’t necessarily a good thing in and of itself: Scientists must take care not to subject such groups to excessive surveillance and data collection. The book discusses this in connection with facial recognition software. When such software was shown to have difficulty recognizing darker-skinned female faces, it was found that this was because the data set on which the software algorithms were trained consisted largely of the faces of white men. Projects aimed at remedying this problem have been compiling databases with greater diversity of faces. Unfortunately, software with an improved ability to detect faces of color can be used by governments and police forces to oppress people of color. This is of particular concern in countries that have poor human rights records, such as Zimbabwe and China, which recently struck a deal to share facial recognition information and technology. Overall, D’Ignazio and Klein argue for what’s known in anthropology as studying up, the too-rare practice of people with relatively little institutional power studying those higher up in the www.americanscientist.org

This map of San Francisco, prepared in 2014 by the Anti-Eviction Mapping Project, uses small, darker-colored dots to represent “Ellis Act” evictions and larger orange dots to indicate the location of bus stops where private shuttles pick up the employees of Silicon Valley technology companies to carry them to work. The Ellis Act allowed landlords to carry out “no fault” evictions by claiming that they were going to go out of the rental business. After the tenants were evicted, the landlords often converted the buildings to condominiums and sold them at a large profit to wealthy Silicon Valley tech company employees who wanted to live near the bus stops. The map makes it clear that many (69 percent) of the evictions that occurred from 2011 through 2013 took place within four blocks of a tech bus stop. From Data Feminism.

power structure. For example, instead of studying a community affected by pollution, researchers could study the polluters. In the context of data feminism, studying up means intentionally collecting and using data to interrogate and challenge those with power, while refusing to participate in data collection that harms minoritized people and communities. An example of data collection that harms such groups is a widely used algorithm that assesses the risk that someone who has been arrested will commit a future crime; in 2016, an investigation by ProPublica determined that Black defendants were more likely than white defendants to be mislabeled as high risk by the algorithm and to be denied bail as a result. Questions about which groups should be represented in data collection are important, but it is even more important to ask who benefits from the data. It may shock some readers to learn that the authors are not necessarily fans of initiatives to promote “data for good” (projects undertaken in the public interest) and initiatives

to promote “data ethics.” (Data ethics initiatives are promising, they say, but often simply serve as a Band-Aid.) According to D’Ignazio and Klein, both of these frameworks fall short when it comes to shifting power to minoritized people and groups; they therefore urge data scientists to focus on equity rather than fairness, and on justice rather than ethics. They aren’t trying to shame anyone; they are simply suggesting ways of distinguishing between projects that aim “for good” and those that aim for liberation. In projects using data for liberation, members of minoritized groups lead the project from the start; they also own the data collected and participate in its analysis, with data scientists acting as facilitators and guides. A series of such projects discussed in the book have been carried out over the past several years in the San Francisco Bay area (see figure above) by the AntiEviction Mapping Project, which consists of “housing justice activists, researchers, data nerds, artists, and oral historians”; some of these projects have involved collaboration with the Eviction 2021



Defense Collaborative, which provides court representation for people who have been evicted. The two groups collect and share systematic data on eviction trends; the goal is not merely to raise awareness but to bring about change. Data Feminism is focused on solutions. For instance, to help ensure that data are not reused inappropriately, the authors recommend adding context in the form of “data user guides,” a concept developed by Western Pennsylvania Regional Data Center. The guides explain the details and purpose of the data collection and may include caveats about the limitations and a discussion of the ethical dimensions of the data. The book also provides many examples of how to “show your work” in ways that give credit to the many people and kinds of knowledge needed to carry out data projects. For example, the authors propose that GitHub repositories of open source code be designed in a way that allows viewers to see all types of contributions to the production of code. The emphasis in the text on process is matched by the process the authors undertook to create the book: They put a draft of the manuscript (akin to a preprint) online and invited community peer review. The draft and public comments on it are still available online

(https://mitpressonpubpub.mitpress .mit.edu/data-feminism). A side-byside comparison with the finished book reveals that several sections contain additions that were suggested by the community reviewers; one such addition recommends moving beyond a gender binary when discussing invisible labor. The final text of the book includes appendixes that contain the authors’ guiding values and the metrics they used to measure their success in addressing structural problems such as racism in both the public draft and the printed book. In this regard, the book is an excellent example of the process that it encourages data scientists to use. Data Feminism covers challenging topics such as structural racism and sexual violence, but it is narrativedriven: The authors make their points by telling detailed stories about how various data projects have been carried out. Free of jargon and easy to read, the book can be enjoyed by scientists in many different fields. The text of each chapter is complemented by a number of instructive data visualizations—charts, graphs, photos, maps, and other figures. A number of these are nontraditional, and some are visually quite compelling. For instance, a figure from the book, titled “Bruises—

Shown here is a small portion of a visualization created by Giogia Lupi. From Data Feminism. 56

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the Data We Don’t See,” depicts the emotional journey of a mother (Kaki King) whose daughter (Cooper) has been diagnosed with idiopathic thrombocytopenic purpura, a disease that presents as bruises and petechiae (minute reddish spots on the skin containing blood). The figure records changes to the daughter’s skin, accompanied by a record of the mother’s feelings as a caregiver. Each day is represented by a white aspen-shaped leaf colored with purple splotches to show intensity of bruising and pink dots representing petechiae (see detail from the figure at lower left). Curved purple and orange lines alongside the leaf represent, respectively, the mother’s fears and hopes, as do her comments, which range from “devastated” to “today I just wanted her to have fun.” The figure uses an expansive definition of data and embodies the principle that emotion should be elevated. Unfortunately, this striking visualization is the only one in the entire book that refers explicitly to disability, and it appears to violate one of the credos of disability advocacy—“Nothing about us without us.” A shortcoming of the book is that the authors’ only metric for holding themselves accountable for addressing ableism (discrimination or prejudice against people with disabilities) is the inclusion of nonvisual methods of data presentation, and the text does not indicate whether blind individuals were involved in the creation of the examples of nonvisual elements provided. Another topic that I wish the book had given more attention to is Indigenous data sovereignty—methods of using data in ways that respect the right to self-determination of Indigenous communities. Data about members of those communities should not be collected, kept, or used without their consent and leadership. Anyone who works with data—and all scientists do, of course—will benefit from reading this book. But the readers who may gain the most from it are those who are trying to use data in the public interest. Data Feminism does such a good job of integrating theories and projects across several fields that it will likely become a touchstone for teaching data science that goes beyond data ethics. Kaitlin Stack Whitney is an assistant professor in science studies and environmental science at the Rochester Institute of Technology. She participates in several initiatives to make open science more accessible and inclusive.

Combating Specious Ideas Greg Laden HOW TO ARGUE WITH A RACIST: What Our Genes Do (and Don’t) Say about Human Difference. Adam Rutherford. 221 pp. The Experiment, 2020. $21.95.


dam Rutherford describes his recent book, How to Argue with a Racist: What Our Genes Do (and Don’t) Say about Human Difference, as a “tool kit” of scientific knowledge that can be used to challenge incorrect claims about race, genes, and ancestry. As a geneticist and evolutionary biologist, he is well qualified to provide the necessary information, and he is an excellent science communicator. His tool kit arrives at an opportune time, when open expression of bigotry is increasingly pushing its way into popular discourse. The book groups misunderstandings about race into four subject areas— pigmentation, ancestry, sports, and intelligence—and devotes a chapter to each. Skin color (and eye color) have long been used to sort humans into a small number of “races,” even though skin color varies continuously across our species. People interested in genealogy—particularly those who are white supremacists—have often extended their attitudes about race into the distant past to claim ancestral racial “purity” or lineal descent from special individuals. Some sports fans believe that top African athletes are endowed with special physical abilities that derive from race. And it has been alleged throughout history that differences in intelligence between groups result from biological factors that have a racial basis. Rutherford notes that although it is easy to make race-based claims, it is much more difficult to refute them. But by deploying a sophisticated understanding of genetics, biology, and behavior, he demonstrates convincingly that those claims are not scientifically valid. Rutherford explains that race is an imprecise, poorly defined term, used colloquially in ways that conflict with what we know about human variation from genetics. Along with words like Black, white, and Asian, race is an www.americanscientist.org

unscientific descriptor. Nevertheless, race is a very real social construct, and people do have a common informal understanding of these descriptors, so it is hard to avoid using them when trying to clarify underlying biological realities across human populations. Stereotypes, myths, and assumptions about race have deep roots in Western culture, and pseudoscience has long been used to defend those assumptions. Well-meaning people as well as overt racists often insist that racial categories are rooted in biology. The claims persist in part because the physical traits used to lump people into crude racial categories are, in fact, determined in part by genetic variation. The important question, Rutherford says, is this: “Are there essential biological (that is, genetic) differences between populations that account for socially important similarities or divisions within or between those populations?”

of supposed racial traits is up to date, clear, and complete. Recent genetic research shows that few genes code for a single trait, and that few traits are coded for by a single gene. Moreover, biological features are the product both of development and of interactions between genes and the environment. Therefore, genetic differences are not organized and distributed across humankind in neat packages that correspond to racial categories. Also, no links have been found between genes and body types, or between genes and particular behaviors, that would support simplistic racist ideas. In the chapter on ancestral purity, Rutherford takes the reader on a startling toboggan ride through family trees and the results of commercial DNA testing. This discussion is a highlight of the book. Every time one goes back a generation in a family tree, the number of ancestors doubles.

Rutherford rejects on multiple grounds the theory that evolutionary selection among slaves was the source of athletic prowess among African Americans today. Here is how Rutherford deconstructs race as a biological concept: Historically, he explains, the word race served as a rough synonym for categories that were more scientific, such as subspecies of animals or varieties of plants—genetically distinct subgroups with multiple correlated characteristics. For members of such subgroups, one expects to be able to correctly predict nontrivial things about the organism’s physiology and behavior just by looking at it. For example, someone who is familiar with dog breeds can identify a springer spaniel and a border collie, and knows which is a hunting dog and which is a herding dog. However, the surface features that we use to put humans into racial categories do not allow us to make accurate predictions about the people in a given category. Rutherford also notes that geographical distance, rather than the boundaries between geographic areas, best accounts for the genetic variation we see among humans. His discussion

Going back a thousand years puts genealogical slots for more than a trillion ancestors into the tree. Clearly, most of those slots for ancestors are filled by a small number of individuals. And the further back one goes, the more it will be the case that the people in one person’s family tree will also appear in the family trees of large numbers of other people. Eventually, the genetic isopoint will be reached: the point in time at which every member of the entire historical population of a geographic area was an ancestor of the entire current population of the area. The isopoint for living Europeans occurred a little over a thousand years ago. The global isopoint occurred much more recently than you might assume; let’s just say that the members of a club of white supremacists meeting in a shack in the woods in Michigan today and the contemporary inhabitants of a Maasai village in Tanzania are related thousands of times over within a timeframe that postdates the rise of civilization. 2021



Racist thinking rests on particularly thin ice in the area of sports. Consider running: There has not been a white athlete fast enough to set an Olympic record for sprinting in four decades, which has led many people to jump to the conclusion that speed is racebased. In the area of endurance, many recent international marathons have been won by Kenyans or Ethiopians. Similar observations have been made across a range of sports. Being of African descent has ostensibly predisposed African Americans genetically to have a physiology that is athletically advantageous. Dozens of genes have been identified in elite athletes that appear to relate to speed and endurance, but it has not been shown that those genes are concentrated in particular ethnic populations. Also, the presence of a given genetic allele may be necessary but not sufficient to promote speed or endurance. Obviously, additional physical factors (such as body shape, metabolic efficiency, and adaptation to altitude) contribute to athletic success, and nurture may be just as important as nature. One race-based explanation for the high level of performance among African-American athletes is the idea that centuries of slavery “bred” individuals with those specific traits, which rests on two assumptions: that slaves with a particular combination of size, strength, and power would have had Statement of ownership, management and circulation (required by 39 U.S.C. 3685). 1. Publication title: American Scientist. 2. Publication number: 2324-0. 3. Filing date: October 1, 2020. 4. Issue frequency: Bimonthly. 5. No. of issues published annually: 6. Annual subscription price: $30. 7. Complete mailing address of known office of publication: P.O. Box 13975, Research Triangle Park, NC 27709-3975. 8. Complete mailing address of headquarters or general business office of publisher: P.O. Box 13975, Research Triangle Park, NC 27709-3975. 9. Full names and complete mailing addresses of publisher, editor, and managing editor: Jamie Vernon, publisher, P.O. Box 13975, Research Triangle Park, NC 27709-3975; Fenella Saunders, editor, P.O. Box 13975, Research Triangle Park, NC 27709-3975; Stacey Lutkoski, managing editor, P.O. Box 13975, Research Triangle Park, NC 27709-3975; 10. Owner: Sigma Xi, The Scientific Research Honor Society, P.O. Box 13975, Research Triangle Park, NC 27709-3975. 11. Known bondholders, mortgagees, and other security holders owning or holding 1 percent or more of total amount of bonds, mortgages, or other securities: None. 12. The purpose, function, and nonprofit status of this organization and the exempt status for Federal income tax purposes: Has not changed during preceding 12 months. 13. Publication Title: American Scientist. 14. Issue Date for Circulation Data: September–October 2019—July–August 2020. 15. Extent and nature of circulation: science. A. Total no. copies: Average no. cop-


American Scientist, Volume 109

an evolutionary advantage, and that this ideal slave phenotype somehow turned out to be the perfect phenotype for all of the different modern sports at which African-American athletes excel. Rutherford points out that if certain genes have made members of some races into superior runners, then there should be dozens, maybe hundreds, of populations contributing to the record books, because those genes are widely distributed. He also provides a better explanation for the dominance of particular populations in certain Olympic sports: Many of the most successful athletes come from countries that provide highly specialized training programs for promising individuals. Rutherford rejects on multiple grounds the theory that evolutionary selection among slaves, whether it occurred naturally or through breeding programs, was the source of athletic prowess among African Americans today: A few centuries is not a long time in evolutionary terms, and the slave population in the United States was highly diverse genetically; also, physical strength would not necessarily have been an advantage among house slaves. Variation in intelligence between racial groups has been measured with IQ tests, and the assessment of that variation is much more complex than is the analysis of variation in sports prowess. IQ is much more difficult to measure ies each issue during preceding 12 months, 41,624; no. copies of single issue published nearest to filing date, 37,210. B. Paid circulation: B1. Mailed outsidecounty paid subscriptions stated on PS Form 3541: average no. copies each issue during preceding 12 months, 23,013; no. copies of single issue published nearest to filing date, 19861. B2. Mailed in-county paid subscriptions: average no. copies each issue during preceding 12 months, 0; actual no. copies of single issue published nearest to filing date, 0. B3. Paid distribution outside the mails including sales through dealers and carriers, street vendors, counter sales, and other paid distribution outside USPS: average no. copies each issue during preceding 12 months, 5,533; no. copies of single issue published nearest to filing date, 5,006. B4. Paid distribution by other classes of mail through the USPS: average no. copies each issue during preceding 12 months, 0; no. copies of single issue published nearest to filing date, 0. C. Total paid distribution: average no. copies each issue during preceding 12 months, 28,546; no. copies of single issue published nearest to filing date, 24,867. D. Free or nominal rate distribution: D1. Free or nominal rate outside-county copies as stated on PS Form 3541: average no. copies each issue during preceding 12 months, 397; no. copies of single issue published nearest to filing date, 379. D2. Free or nominal rate in-county copies as stated on PS Form 3541: average no. copies each issue during preceding 12 months, 0; actual no. copies of single issue pub-

than speed on a race track, and we don’t know a great deal about what causes differences between groups in performance on IQ tests. Indeed, because IQ tests provide highly variable results, it is common to scale the results for a given version of the test so that the average score is 100 and the other scores fall into a normal distribution (a bell curve). Black populations around the world have been found on average to score 10 to 15 points lower than other groups on IQ tests. Genetic factors probably don’t account for this, because African countries are so genetically diverse; it seems much more likely that environmental factors have created the discrepancy. Dozens of genetic variants have been found to correlate with performance on cognitive tests, but we don’t know what most of those genes do. In the book’s conclusion, Rutherford observes that “Race is real because we perceive it. Racism is real because we enact it. Neither race nor racism has foundations in science.” We have a duty, therefore, “to contest the warping of scientific research . . . to justify prejudice.” Those are strong words, and true ones. I highly recommend this book. Greg Laden is a biological anthropologist and educator who has worked in the Democratic Republic of Congo and South Africa. He writes a blog at gregladen.com/blog.

lished nearest to filing date, 0. D3. Free or nominal rate copies mailed at other classes mailed through the USPS: average no. copies each issue during preceding 12 months, 0; actual no. copies of single issue published nearest to filing date, 0. D4. Free or nominal rate outside the mail: average no. copies each issue during preceding 12 months, 351; no. copies of single issue published nearest to filing date, 311. E. Total free or nominal rate distribution: average no. copies each issue during preceding 12 months, 748 no. copies of single issue published nearest to filing date, 690. F. Total distribution: average no. copies each issue during preceding 12 months, 29,294; no. copies of single issue published nearest to filing date, 25,557. G. Copies not distributed: average no. copies each issue during preceding 12 months, 12,330; no. copies of single issue published nearest to filing date, 11,653. H. Total: average no. copies each issue during preceding 12 months, 41,624; no. copies of single issue published nearest to filing date, 37,210. I. Percent paid: average no. copies each issue during preceding 12 months, 97 percent; no. copies of single issue published nearest to filing date, 97 percent. 16. Total circulation includes electronic copies: no. copies of single issue published nearest to filing date: A. paid electronic copies, 7,452. B. Total paid print copies + paid electronic copies, 35,998. C. Total print distribution + paid electronic copies, 36,746. D. Percent paid: 98%. 50% of all distributed copies (electronic & print) are paid above a nominal price.

2021 STUDENT RESEARCH SHOWCASE Jay Gopal, 2020 People’s Choice Award Winner

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Call for Abstracts: Online Research Presentations • • • •

Students build a website containing a slideshow, abstract, and a short video about their research Open to high school, undergraduate, and graduate students Division winners are awarded $500 A public vote selects the $250 People’s Choice Award winner For more information and to register: email [email protected]

Timeline December 1, 2020: Abstract submission begins March 26, 2021:

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Sigma Xi F

Distinguished Lecturers 2021–2022

or the 83rd year, Sigma Xi presents its panel of expenses related to hosting a Distinguished Lecturer. Distinguished Lecturers as an opportunity for Applications must be submitted online by March 1, chapters to host visits from outstanding individu2021, for funds to be available the next fiscal year. als who are at the leading edge of science. These visitors Additional support for the program comes from the communicate their insights and excitement on a broad American Meteorological Society and the National range of topics. Cancer Institute. Lecturer biographies, contact The Distinguished Lecturers are available from July information, and additional details can be found online 1, 2021, to June 30, 2022. Each speaker has consented to under the Lectureship Program link at www.sigmaxi.org a modest honorarium toor by sending an email to gether with full payment of [email protected]. Chapter Subsidy Application Deadline: travel costs and subsistence. Marc Imhoff, Chair Local chapters may apCommittee on Lectureships ply for subsidies to support

March 1, 2021

https://www.sigmaxi.org/lectureships Julie Demuth, Project Scientist II at the National Center for Atmospheric Research (NCAR) Mesoscale & Microscale Meteorology Lab (MMM) Understanding Public Risk Perceptions and Responses for Improved Tornado Risk Communication (P, G, S) • A Longitudinal Analysis of People’s Risk Perceptions and Responses During a Real-World Hurricane Threat (S) Andrew Fisher, Professor, Hydrogeology, Earth and Planetary Sciences Department, University of California at Santa Cruz Mapping, Modeling, Measuring, and Monetizing Enhanced Groundwater Recharge with Stormwater (P, G, S) • Subseafloor Experiments and Models Reveal Complex Patterns of Coupled Fluid-Heat-Solute Transport through the Ocean Crust (P, G, S) Agustín Fuentes, the Edmund P. Joyce, C.S.C., Professor of Anthropology, Chair of the Department of Anthropology, University of Notre Dame Why We Believe: Evolution and the Human Way of Being (P, G) • The Creative Species: Imagination and Collaboration in Human Evolution (P, G) • What Race Is, and What It Is Not . . . And Why It Matters (P, G, S)

Can You Trust What You See? The Magic of Visual Perception (P, G, S) • Advancements in Artificial Intelligence (AI): Technology, Risks, Applications, and Implications (P, G, S) • The Artificial Intelligence (AI) Revolution in Medicine (P, G, S)

Heather McKillop, Thomas & Lillian Landrum Alumni Professor, Louisiana State University Submerged Ancient Maya Salt Works, Belize (G, S) • Using 3D Technology in Underwater Maya Archaeology at the Paynes Creek Salt Works, Belize (G, S) • Sea Level Rise Submerged Ancient Maya Coastal Sites (S) • Salt Production and the Ancient Maya Marketplace Economy (G, S) • Ancient Maya Canoe Travel and Sea Trade (G, S) Laurie McNeil, Bernard Gray Distinguished Professor, University of North Carolina at Chapel Hill OPV, OLED, OFET, Oh My! Photons, Electrons, and Phonons in Organic Semiconductors (S) • Changing the Climate for Women in Science (G) • Good Vibrations: The Interplay of Music and Physics (P)

Kristie Macrakis, Professor, Director of Graduate Studies, Georgia Institute of Technology

David Pfennig, Professor, Department of Biology, University of North Carolina at Chapel Hill

Passing the Global Espionage Torch: How Britain Helped the U.S. Expand Its Eavesdropping Capabilities (P, G) • Our Machine in Havana: How We Really Found Missiles on Cuba (P, G) • Invisible Ink Revealed (P, G)

Plasticity, Epigenetics, and Evolution (P, G) • Life Imitating Life: The Evolution of Mimicry (P, G, S) • Phenotypic Plasticity and the Evolutionary Origins of Novel Traits (S)

P (Public), G (General), S (Specialized)


Oge Marques, Professor, Computer Engineering, Florida Atlantic University

American Scientist, Volume 109

Details available at https://www.sigmaxi.org/lectureships



CDC/Alissa Eckert/Dan Higgins

Guest Distinguished Lecturers


n March 2020, as the scale of the COVID-19 epidemic was becoming apparent, the Committee on Lectureships organized a Special Distinguished Lecturer series and invited scientists who are at the forefront of COVID-19 research, public policy, and communication to address the pandemic from different perspectives. The six selected speakers engaged in online conversations and shared emerging research findings with Sigma Xi members and the public. The program focused on various topics related to COVID-19 including vaccine development, genetic structure and evolution, the use of big data to track the pandemic, and public health strategies to control viral transmission. The Society partnered with science communicator and producer and host of the This Week in Science podcast Kirsten (Kiki) Sanford to interview the speakers and moderate the discussions. All sessions were held virtually, and recordings are available on the Sigma Xi website. Special thanks to Janelle Simmons, Sigma Xi Manager of Programs; Eman Ghanem, Sigma Xi Director of Membership, Chapters,

Shweta Bansal, Provost’s Distinguished Associate Professor of Biology, Georgetown University

Mark Peeples, Principal investigator and member of the Center for Vaccines and Immunity at the Abigail Wexner Research Institute at Nationwide Children’s Hospital and a professor of Pediatrics and of Molecular & Cellular Biochemistry at The Ohio State University College of Medicine

Jessie Abbate, Infectious Disease Epidemiologist & Data Analysis Consultant, World Health Organization (Africa Region)

Michael T. Osterholm, Professor, the University of Minnesota, and director of the Center for Infectious Disease Research and Policy

David Deamer, Research Professor, Biomolecular Engineering, University of California at Santa Cruz

Peter J. Hotez, Dean of the National School of Tropical Medicine and Professor of Pediatrics and Molecular Virology & Microbiology, Baylor College of Medicine

and Programs; Jamie Vernon, Sigma Xi Executive Director and CEO; Joel Primack, Distinguished Professor of Physics Emeritus at the University of California at Santa Cruz; Tammy Maldonado, instructor in the Department of Integrative Physiology at the University

of Colorado Boulder; and Committee on Lectureships chair Marc Imhoff, Visiting Research Scientist at the University of Maryland’s Earth System Science Interdisciplinary Center (ESSIC), for helping with the organization and successful execution of this series.

Luisa Rebull, Associate Research Scientist, California Institute of Technology IPAC

Corinna Ross, Associate Professor of Biology, Texas A&M University–San Antonio

More Than Your Eyes Can See: Infrared Light (P) • Getting Your Hands on Real Astronomy Data (P, G, S) • Stellar Rotation in Clusters with K2 (S)

The Search for the Fountain of Youth (P, G, S) • Early Development, Obesity, and Aging: What We Can Learn from Monkeys (P, G, S) • Monkeys and Children and Science, Oh My! An Attempt to Balance a Career in Science with Motherhood (G, S)

Federico Rosei, Professor, Director and UNESCO Chair, NRS Centre for Energy, Materials and Telecommunications

Danielle Wood, Assistant Professor and Director of the Space Enabled Research Group, Massachusetts Institute of Technology

Energy and Society: What Type of Energy for the Future of Humanity? (P) • Survival Skills for Scientists (G) • Multifunctional Materials and Their Applications in Emerging Technologies (G, S)

P (Public), G (General), S (Specialized)


Technology from Space Enables Sustainable Development on Earth (P, G, S) • Designing Complex Systems in Support of Sustainable Development Using Systems Architecture (G, S) • Space Technology for the Development Leader (S)

Details available at https://www.sigmaxi.org/lectureships




Volume 30 Number 01

January–February 2021


Call for Nominations: Sigma Xi Elections Sigma Xi, The Scientific Research Honor Society is seeking nominations for qualified candidates to fill the president-elect and treasurer positions and vacancies for representation of regions and constituencies for terms beginning July 1, 2022. 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. Election to treasurer carries a full four-year term beginning July 1, 2022, through June 30, 2026. Election to president-elect carries a full threeyear term, each year with distinct title, duties, and responsibilities. Failure to complete any part of the three-year term will end the term in full: President-elect: July 1, 2022–June 30, 2023 President: July 1, 2023–June 30, 2024 Immediate past president: July 1, 2024–June 30, 2025

Nominations for the president-elect and treasurer positions should be submitted to [email protected] by March 2, 2021. For all other positions, submit nominations to [email protected] by June 30, 2021.

continued on page 64

From the President A Historic Occasion At the time of my writing this letter, two significant events have occurred. First, Sigma Xi has successfully executed its first virtual Annual Meeting and Student Research Conference. This year’s meeting, titled Hacking the Brain: The Intersection of Art and Neuroscience, was a unique experience showcasing the artistic components and applications of scientific research. The participation statistics were amazing! We had the highest number of participants in five years, including international participants from more than 10 countries. We had more than 300 student projects presented and over 45 percent of the professional presenters were women. We had the honor of presenting the Gold Key Award to Dr. Walter E. Massey, who had an outstanding conversation afterward with 2017 Nobel Prize winner Kip Thorne, moderated by NPR Science Correspondent Joe Palca. We were entertained by award-winning science rapper Baba Brinkman and inspired by John P. McGovern Science and Society Award winner and former astronaut Bonnie Dunbar. This year’s Annual Meeting also saw the fruition of Immediate Past President Geraldine Richmond’s vision of Sigma Xi Fellows with the induction of the inaugural cohort. This event would not have been possible without the conference sponsors, which included more than 30 academic institutions and organizations. The Burroughs Wellcome Fund lead the sponsorship of this conference. They are a longtime partner of Sigma Xi, and we appreciate their continued support. The second event that happened during our Annual Meeting is the announcement that Kamala Harris is set to become the first female Vice President of the United States. An alumna of Howard University, with a B.S. in economics, she has achieved a level of leadership for women unheard of in the history of the United States. Although not a scientist, she is a woman in STEM as defined by the National Science Foundation. More important, she represents a rapidly growing cadre of women in STEM who are rising to national and international leadership. I am sure that our conference participants and our award recipients would agree that this is a great time in our country, but also an uncertain time. With the foundations of Sigma Xi, companions in zealous research, we will solve the COVID-19 crisis, address climate change, and improve our society. Sigma Xi remains a force for truth in science, and we will continue to champion scientific research as we have done for the past 134 years.

Sigma Xi Today is managed by Amia Butler and designed by Chao Hui Tu.

Sonya Smith 62

Sigma Xi Today


Grants in Aid of Research Recipient Profile: Dominic Mier Grant: $1,000 in Spring 2019 Education level at time of the grant: Graduate student

Project Description: In the lab Dominic studies the minor spliceosome. The spliceosome is in charge of removing noncoding introns from RNA and joining the remaining exons, forming a mature transcript that can be properly translated to protein. The minor spliceosome specifically removes U12 introns, a small subsection making up less than 0.5 percent of all introns in an organism. Research on the minor spliceosome has shed light on several human diseases in recent years, highlighting the importance of further insight into its components. Dominic’s research question involved investigating the role a specific protein, ARMC7, played in the minor spliceosome. Dominic and his team identified a mutant that seemed to be caused by an insertion into the ARMC7 gene locus, but map-

ping wasn’t able to confirm precisely where the causative mutation was. After receiving the grant funding, they were able to design a CRISPR-Cas9 system to attempt to partially knock out ARMC7 function, which would allow them to investigate its role. There have yet to be any mutants recovered, but they have moved into further characterization by investigating what proteins ARMC7 may interact with. He hopes this will give him further insight into the role it plays in the cell. How has the project influenced Dominic as a scientist? “This project has really fostered my growth as a scientist,” Dominic says. This was his first big project. “It taught me a lot about research, but also the fortitude necessary in a research environment,” he states.

Where is he now? Dominic is currently wrapping up his graduate studies. He has begun searching for jobs and is excited about all the opportunities he may have to contribute to research in the field of biology.

Call for Abstracts: 2021 Student Research Showcase Students are invited to submit abstracts of their research by March 26 for the 2021 Student Research Showcase, Sigma Xi’s online science communication competition. The eighth annual online competition challenges high school through graduate school students to create a website containing a slideshow, video, and abstract about their research. The Student Research Showcase is a unique opportunity for students to develop effective science communication skills, which every researcher should have. The showcase invites submissions in the following research categories: Agricultural, Soil, and Natural Resources; Anthropology; Cell Biology and Biochemistry; Chemistry; Ecology and Evolutionary Biology; Engineering; Environmental Sciences; Geosciences; Human Behavioral and Social Sciences; Math and Computer Science; Microbiology and Molecular Sigma Xi 2021 Student Research Showcase


Biology; Physics and Astronomy; and Physiology and Immunology. Presentation websites must be submitted by April 16 and judging will take place April 26–May 10, 2021. Judges will select top presenters in each research category. During the judging period, more than 60 Sigma Xi members volunteer as judges to evaluate students’ submissions and engage in digital conversations with presenters through their websites. Top presenters will be selected in the high school, undergraduate, and graduate divisions and will receive up to $500 awards. A public vote selects one presentation for a $250 People’s Choice Award. All participants receive a certificate of participation. Learn more at www.sigmaxi.org/srs

2021 January–February 63


Virtual Annual Meeting and Student Research Conference Discussed

Science–Art Collaborations Sigma Xi members, researchers, artists, and students came together virtually November 5–8 for the 2020 Sigma Xi Annual Meeting and Student Research Conference. The theme of this year’s meeting was Hacking the Brain: The Intersection of Art and Neuroscience, what art and science achieve together that neither could accomplish alone. The conference was attended by more than 800 research professionals, students, and exhibitors. The event began with a business meeting for delegates, who represented Sigma Xi chapters and the Membership-at-Large constituency. The Society's Board of Directors and Assembly of Delegates unanimously voted in favor of adopting a Diversity, Equity, and Inclusion resolution. Sigma Xi leaders and president-elect candidates provided updates and discussed business of the Society. Plenary speakers included Sigma Xi’s 2020 Gold Key award winner Walter E. Massey, who reflected on his career and addressed social justice and diversity in STEM. His remarks were

followed by a discussion with Nobel Laureate Kip Thorne and NPR Science Correspondent Joe Palca. Additional plenary speakers included all but one of Sigma Xi’s 2020 award winners. Keynote sessions included Barbara Landau (Dick and Lydia Todd Professor of Cognitive Science at Johns Hopkins University), who gave a talk titled “When an Amnesic Artist Remembers.” Rachael Cusick discussed “Radiolab Presents: G,” Radiolab’s 2019 documentary series on intelligence that had her diving into the search for genius. Anjan Chatterjee (University of Pennsylvania) addressed the emerging field of neuroaesthetics and argued that our brains respond automatically to our aesthetic environment. The closing keynote session was presented by Larry S. Sherman (Oregon Health and Science University) who integrated live music segments in his discussion on why “Every Brain Needs Music.” Approximately 400 high school, undergraduate, and graduate students attended the meeting and presented their research during the Student Re-

Walter E. Massey

search Conference. Sigma Xi members evaluated the students on their scientific thought, method, and communication skills. Judges selected top presenters in each division and research discipline for awards including a $150 monetary gift, a commemorative medal, and nomination to Sigma Xi associate membership, with the initiation fee and first year’s dues waived.

Save the date 2021 Annual Meeting and Student Research Conference November 4–7 in Niagara Falls, New York

Call for Nominations: Sigma Xi Elections

continued from page 62

The following positions carry a three-year term beginning July 1, 2022, and ending June 30, 2025. Board of Directors: • North Central Region • Southwest Region • Area Groups, Industries, State & Federal Laboratories Constituency Group • Comprehensive Colleges & Universities Constituency Group Associate Directors: • Northeast Region • Baccalaureate Colleges Constituency Group • Canadian/International Constituency Group • Mid-Atlantic Region 64 Sigma Xi Today

Committee on Nominations: three-year term beginning immediately following the 2021 elections. • Membership-at-Large Constituency Group • Research & Doctoral Universities Constituency Group • Northwest Region • Southeast Region Please visit www.sigmaxi.org/2021-elections to view a list of duties and responsibilities for each position. Selfnominations are welcomed and will be considered. The elections will take place immediately following Sigma Xi’s Annual Meeting on November 2021.

November 4–7 2021

SAVE THE DATE Sigma Xi Annual Meeting and Student Research Conference 2021

Dr. Robert T. Pennock, Program Chair President-Elect, Sigma Xi University Distinguished Professor, Michigan State University