A NEW THEORY OF OBESITY PAGE REVERSING DEATH PAGE Are ultraprocessed foods to blame? 38 Partially revived pig brains raise hard questions 34 WIN GED How pterosaurs evolved to dominate TER ROR the Mesozoic skies PLUS ROOM-TEMPERATURE SUPERCONDUCTORS Are scientists nearing a breakthrough? PAGE 46 PRESCHOOL PEDAGOGY Why instilling focus and language skills fosters success PAGE 68 OCTOBER 2019 SCIENCE IN CRISIS ScientificAmerican.com The raging debate over statistical significance PAGE 62 © 2019 Scientific American OCTOBER 2019 VOLUME 321, NUMBER 4 46 EVOLUTION deliver the elusive room- 26 Monsters of temperature superconductor? the Mesozoic Skies By Bob Henderson Fossils and mathematical modeling are helping to answer AGRICULTURE long-standing questions about 54 Restoring Rice pterosaurs. By Michael B. Habib Biodiversity NEUROSCIENCE Long-forgotten varieties of the 34 Is Death Reversible? staple crop can survive flood, An experiment that partially drought and other calamities. revived slaughterhouse The challenge is bringing pig brains raises questions about them back. By Debal Deb the precise end point of life. STATISTICS By Christof Koch 62 A Significant Problem NUTRITION Standard scientific methods are 38 Obesity on the Brain under fire. Will anything change? The cause of the obesity epidemic By Lydia Denworth may not be any single class of nutrient. “Ultraprocessed” EDUCATION ON THE COVER Tupandactylus imperator, a pterosaur, patrolled foods may fool our brains into 68 Smart Start the skies during the Cretaceous period. Like a overeating. By Ellen Ruppel Shell Kids in preschools that encourage number of other pterosaurs from this time, it had PHYSICS them to play with language and extreme anatomical features, including a gigan- focus their attention do better tic head and neck compared with the rest of its 46 The Stuff of Dreams body. Researchers have finally begun to under­ Could new theoretical and in school and later life. stand how these bizarre creatures could fly. computational advances finally By Lisa Guernsey Illustration by Chase Stone. 2 Scientific American, October 2019 Photograph by Spencer Lowell © 2019 Scientific American 6 From the Editor 8 Letters 10 Science Agenda Chinese biomedicine confronts an ethical crossroads. By the Editors 11 Forum Boosting STEM education can help avoid job shortfalls down the line. By Rick Lazio and Harold Ford, Jr. 12 Advances Teaching anatomy through virtual reality. A surprising 11 illusion from a common visual correction. Antibiotics in scorpion venom. A tabletop gravitational-wave detector. 22 The Science of Health Losing weight may lower the risk of cancer. By Claudia Wallis 24 Ventures Why buying carbon offsets cannot assuage our guilt about air travel forever. By Wade Roush 76 Recommended Wonders to behold in the sky. How scientists and spies stopped the Nazis from building an atomic bomb. 12 Gravity remains a mystery to learn from. Untold stories of mathematical Americans. By Andrea Gawrylewski 77 The Intersection For better or for worse, Google Maps changes our sense of direction. By Zeynep Tufekci 78 Anti Gravity The greatest predator of human beings in history is the mosquito. By Steve Mirsky 79 50, 100 & 150 Years Ago 80 Graphic Science Cleaning up the ways we produce and consume energy. 76 By Mark Fischetti and Jan Willem Tulp Scientific American (ISSN 0036-8733), Volume 321, Number 4, October 2019, published monthly by Scientific American, a division of Nature America, Inc., 1 New York Plaza, Suite 4500, New York, N.Y. 10004-1562. Periodicals postage paid at New York, N.Y., and at additional mailing offices. Canada Post International Publications Mail (Canadian Distribution) Sales Agreement No. 40012504. Canadian BN No. 127387652RT; TVQ1218059275 TQ0001. Publication Mail Agreement #40012504. Return undeliverable mail to Scientific American, P.O. Box 819, Stn Main, Markham, ON L3P 8A2. Individual Subscription rates: 1 year $49.99 (USD), Canada $59.99 (USD), International $69.99 (USD). Institutional Subscription rates: Schools and Public Libraries: 1 year $84 (USD), Canada $89 (USD), International $96 (USD). 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Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. 4 Scientific American, October 2019 © 2019 Scientific American FROM THE EDITOR Curtis Brainard is acting editor in chief of Scientific American. that number has dwindled to about 6,000 varieties across India Dragon Up to­­day. Thankfully, as he writes in “Restoring Rice Biodiversity,” starting on page 54, conservationist Debal Deb has made it his For me, there’s nothing particularly special about seeing a small life’s work to redress this problem. Cessna take to the air. But watching an Airbus A380, the world’s Whether it’s rice or wheat, we should all eat more whole largest commercial airliner, ascend is something altogether dif- grains and more whole foods in general, but markets in the U.S. ferent. The way it lumbers into the sky just doesn’t seem real. Yet and elsewhere are littered with “ultraprocessed” foods, includ- mechanical and aerodynamic adaptations make flight possible ing candy bars and potato chips, as well as less obvious things for such bulky craft. like flavored yogurt and vodka. New research, which journalist I imagine I would’ve had the same impression (and a dose of Ellen Ruppel Shell describes in “Obesity on the Brain,” suggests terror) watching a hulking pterosaur take wing, especially com- that these unnatural concoctions disrupt gut-brain signals in a pared with the smaller feathered dinosaurs and birds that way that encourages overeating. More fruits and vegetables, pref- evolved later. Pterosaurs were the first vertebrates to fly, and erably of heirloom varieties, please! Graze on over to page 38. while some were quite small, others were enormous. And like Elsewhere, scientists recently used a small device called a today’s jumbo jets, an intricate set of physiological adaptations, diamond anvil cell to apply about half the pressure at the center which paleontologist Michael B. Habib details in this issue’s cov- of the earth to a mix of lanthanum and hydrogen. Then they er story, “Monsters of the Mesozoic Skies,” allowed them to lift shot the mash with a laser and synthesized an entirely new off. They were quadrupedal and had massive necks, for instance, material, lanthanum hydride, in hopes of finding a long-coveted much like the fearsome dragons in Game of Thrones, which room-temperature superconductor. Such a substance, which fer- inspired Habib and his colleagues when they were naming one ries a current without resistance, could accomplish technologi- of the pterosaur species. Turn to page 26. cal wonders. Be­­ginning on page 46, journalist Bob Henderson Pterosaurs are now gone, as are, unfortunately, most of the explains in “The Stuff of Dreams” how theory and computer 110,000 or so distinct varieties of rice that were once planted modeling are now guiding a decades-old quest that was once across India. Some could tolerate flood, drought, salt and pesti- based mostly on guesswork and luck. lence; some had unique nutritional value; and some were just Of course, whether it’s studying ancient creatures, biodiver- uniquely pleasant and used in special rituals. With the Green sity or something else, all science involves a bit of conjecture and Revolution in the 1950s and 1960s, the government began to serendipity. That’s part of what makes the process of research focus on high-yield cultivars, which can produce a lot of grain and discovery so frustrating and ever so delightful. Fortune may but are expensive and vulnerable to environmental assaults, and favor the bold, but it rewards inquisitive minds as well. BOARD OF ADVISERS Drew Endy Alison Gopnik Satyajit Mayor Daniela Rus Leslie C. Aiello Professor of Bioengineering, Professor of Psychology and Senior Professor, Andrew (1956) and Erna Viterbi Professor President, Wenner-Gren Foundation Stanford University Affiliate Professor of Philosophy, National Center for Biological Sciences, of Electrical Engineering and Computer for Anthropological Research Nita A. Farahany University of California, Berkeley Tata Institute of Fundamental Research Science and Director, CSAIL, M.I.T. Robin E. Bell Professor of Law and Philosophy, Lene Vestergaard Hau John P. Moore Eugenie C. Scott Research Professor, Lamont-Doherty Director, Duke Initiative for Mallinckrodt Professor of Physics and Professor of Microbiology and Earth Observatory, Columbia University Chair, Advisory Council, Science & Society, Duke University of Applied Physics, Harvard University Immunology, Weill Medical College Emery N. Brown National Center for Science Education Edward W. Felten Hopi E.