Consider, for example, the following conundrum (Case 1), first proposed by the late philosopher Philippa Foot:

  A railway trolley is hurtling down a track. In its path are five people who are trapped on the line and cannot escape. Fortunately, you can flip a switch that will divert the trolley down a fork in the track away from the five people—but at a price. There is another person trapped down that fork, and the trolley will kill him or her instead. Should you hit the switch?

  Most of us experience little difficulty when deciding what to do in this situation. Although the prospect of flipping the switch isn’t exactly a nice one, the utilitarian option—killing just the one person instead of five—represents the “least worst choice.” Right?

  Now consider the following variation (Case 2), proposed by the philosopher Judith Jarvis Thomson:

  As before, a railway trolley is speeding out of control down a track toward five people. But this time you are standing behind a very large stranger on a footbridge above the tracks. The only way to save the five people is to heave the stranger over. He will fall to a certain death. But his considerable girth will block the trolley, saving five lives. Question: Should you push him?

  Here you might say we’re faced with a “real” dilemma. Although the score in lives is precisely the same as in the first example (five to one), playing the game makes us a little more circumspect and jittery. But why?

  Greene believes he has the answer. It has to do with different climatic regions in the brain.

  Case 1, he proposes, is what we might call an impersonal moral dilemma and involves those areas of the brain, the prefrontal cortex and posterior parietal cortex (in particular, the anterior paracingulate cortex, the temporal pole, and the superior temporal sulcus), principally implicated in our objective experience of cold empathy: in reasoning and rational thought.

  Case 2, on the other hand, is what we might call a personal moral dilemma. It hammers on the door of the brain’s emotion center, known as the amygdala—the circuit of hot empathy.

  Just like most normal members of the population, psychopaths make pretty short work of the dilemma presented in Case 1. Yet—and this is where the plot thickens—quite unlike normal people, they also make pretty short work of Case 2. Psychopaths, without batting an eye, are perfectly happy to chuck the fat guy over the side.

  To compound matters further, this difference in behavior is mirrored rather distinctly in the brain. The pattern of neural activation in both psychopaths and normal people is well matched on the presentation of impersonal moral dilemmas—but dramatically diverges when things get a bit more personal.

  Imagine that I were to pop you into a functional MRI machine and then present you with the two dilemmas. What would I observe as you went about negotiating their moral minefields? Just around the time that the nature of the dilemma crossed the border from impersonal to personal, I would see your amygdala and related brain circuits—your medial orbitofrontal cortex, for example—light up like a pinball machine. I would witness the moment, in other words, that emotion puts its money in the slot.

  But in a psychopath, I would see only darkness. The cavernous neural casino would be boarded up and derelict—the crossing from impersonal to personal would pass without any incident.

  The Psychopath Mix

  The question of what it takes to succeed in a given profession, to deliver the goods and get the job done, is not all that difficult when it comes down to it. Alongside the dedicated skill set necessary to perform one’s specific duties—in law, in business, in whatever field of endeavor you care to mention—exists a selection of traits that code for high achievement.

  In 2005 Belinda Board and Katarina Fritzon, then at the University of Surrey in England, conducted a survey to find out precisely what it was that made business leaders tick. What, they wanted to know, were the key facets of personality that separated those who turn left when boarding an airplane from those who turn right?

  Board and Fritzon took three groups—business managers, psychiatric patients, and hospitalized criminals (those who were psychopathic and those suffering from other psychiatric illnesses)—and compared how they fared on a psychological profiling test.

  Their analysis revealed that a number of psychopathic attributes were actually more common in business leaders than in so-called disturbed criminals—attributes such as superficial charm, egocentricity, persuasiveness, lack of empathy, independence, and focus. The main difference between the groups was in the more “antisocial” aspects of the syndrome: the criminals’ lawbreaking, physical aggression, and impulsivity dials (to return to our analogy of earlier) were cranked up higher.

  Other studies seem to confirm the “mixing deck” picture: that the border between functional and dysfunctional psychopathy depends not on the presence of psychopathic attributes per se but rather on their levels and the way they are combined. Mehmet Mahmut and his colleagues at Macquarie University in Sydney, Australia, have recently shown that patterns of brain dysfunction (specifically, patterns in orbitofrontal-cortex functioning, the area of the brain that regulates the input of the emotions in decision making) observed in both criminal and noncriminal psychopaths exhibit dimensional rather than discrete differences. This, Mahmut suggests, means that the two groups should not be viewed as qualitatively distinct populations but rather as occupying different positions on the same continuum.

  In a similar (if less high-tech) vein, I asked a class of first-year undergraduates to imagine they were managers in a job placement company. “Ruthless, fearless, charming, amoral, and focused,” I told them. “Suppose you had a client with that kind of profile. To which line of work do you think they might be suited?”

  Their answers couldn’t have been more insightful: CEO, spy, surgeon, politician, the military . . . they all popped up in the mix. Among serial killer, assassin, and bank robber.

  “Intellectual ability on its own is just an elegant way of finishing second,” one successful CEO told me. “Remember, they don’t call it a greasy pole for nothing. The road to the top is hard. But it’s easier to climb if you lever yourself up on others. Easier still if they think something’s in it for them.”

  Jon Moulton, one of London’s most successful venture capitalists, agrees. In a recent interview with the Financial Times, he lists determination, curiosity, and insensitivity as his three most valuable character traits.

  No prizes for guessing the first two. But insensitivity? The great thing about insensitivity, Moulton explains, is that “it lets you sleep when others can’t.”

  Contributors’ Notes

  Natalie Angier, a science columnist for the New York Times, is the author of Woman: An Intimate Geography and The Canon: A Whirligig Tour of the Beautiful Basics of Science, among other books. She decided to tackle the topic of infinity when her sixteen-year-old daughter came home with an amusing calculus assignment. Imagine a battle between two superheroes, the teacher said, named Captain Zero and Infinitus. Who would win and under what circumstances? “It was a lesson about limits,” her daughter said. The limits of infinity? Irresistible.

  Rick Bass is the author of thirty-one books of fiction and nonfiction. He lives in northwest Montana’s Yaak Valley, where he is a board member of the Yaak Valley Forest Council and Round River Conservation Studies. His stories and essays have been anthologized in The Best American Short Stories, The Best Spiritual Writing, and The Best American Travel Writing.

  Mark Bowden is an author and longtime journalist, best known for his book Black Hawk Down. Once upon a time he was a science writer for the Philadelphia Inquirer.

  Gareth Cook is a Pulitzer Prize–winning magazine journalist and a regular contributor to NewYorker.com. His work has appeared in the New York Times Magazine, Wired, Scientific American, Washington Monthly, the Boston Globe, and elsewhere. He is the editor of Scientific American’s Mind Matters neuroscience blog and the series editor of The Best American Infographics. He was the Globe’s science reporter for seven years,
one of the founders of the Globe’s Sunday Ideas section, and then its editor from 2007 to 2011, when he was named a Sunday columnist. He has also worked for Washington Monthly, Foreign Policy, U.S. News & World Report, and the Boston Phoenix. This is the second time his work has appeared in The Best American Science and Nature Writing.

  David Deutsch, a University of Oxford physicist and the inventor of the concept of universal quantum computers, says he got interested in physics as a child when he rebelled at the claim that no one can understand everything that is understood.

  Kevin Dutton is a research psychologist at the Calleva Research Centre for Evolution and Human Sciences, Magdalen College, University of Oxford. He is a member of the Royal Society of Medicine and the Society for the Scientific Study of Psychopathy. Dutton’s first book, Flipnosis: The Art of Split-Second Persuasion, first published in 2010 and since translated into eighteen languages, documents his quest—from the political genius of Winston Churchill to the malign influence of some of the world’s top con artists—for the psychological “DNA” of persuasion. His second book, The Wisdom of Psychopaths: Lessons in Life from Saints, Spies, and Serial Killers, was published in 2012. In it Dutton explores the positive side of being a psychopath and discovers firsthand, in a groundbreaking “how to make a psychopath” experiment, what it’s like to be one. The effects have since worn off.

  Sylvia A. Earle is the former chief scientist of the U.S. National Oceanic and Atmospheric Administration and a National Geographic Explorer-in-Residence, as well as the founder of the Sylvia Earle Alliance, Mission Blue, and Deep Ocean Exploration and Research. Dr. Earle has been called “Her Deepness” by The New Yorker and the New York Times and has been named a “Living Legend” by the Library of Congress and the first “Hero for the Planet” by Time. She has lectured in more than eighty countries, led more than a hundred expeditions—including the first team of women aquanauts—and logged 7,000 hours underwater, with a record solo dive to 1,000 meters and ten saturation dives.

  Artur Ekert pioneered entanglement-based cryptography as a graduate student. He is now the director of the Center for Quantum Technologies in Singapore and a professor at Oxford’s Mathematical Institute. He is a keen pilot and diver.

  Brett Forrest has contributed to Playboy, Vanity Fair, The Atlantic, and National Geographic. He has lived in Russia, Ukraine, and Brazil.

  Keith Gessen was born in Russia in 1975 and emigrated to the United States with his family in 1981. He is a founding editor of n+1 and the author of All the Sad Young Literary Men, a novel.

  Jerome Groopman holds the Dina and Raphael Recanati Chair of Medicine at Harvard Medical School and is chief of experimental medicine at the Beth Israel Deaconess Medical Center. He received his BA from Columbia College summa cum laude and his MD from Columbia College of Physicians and Surgeons in New York. He served his internship and residency in internal medicine at Massachusetts General Hospital and held specialty fellowships in hematology and oncology at the University of California, Los Angeles, and the Dana-Farber/Boston Children’s Hospital Cancer Center, Harvard Medical School, in Boston. He serves on many scientific editorial boards and has published more than 180 scientific articles. In 2000 he was elected to the Institute of Medicine of the National Academies. He writes regularly about biology and medicine for lay audiences as a staff writer at The New Yorker. In 2011 he coauthored, with Dr. Pamela Hartzband, Your Medical Mind: How to Decide What Is Right for You.

  Benjamin Hale is the author of the novel The Evolution of Bruno Littlemore, which was nominated for the Dylan Thomas Prize and the New York Public Library’s Young Lions of Fiction Award. He is a recipient of a Michener-Copernicus Fellowship and the Bard Fiction Prize, and his writing has appeared in Harper’s Magazine, Conjunctions, the New York Times, The Millions, and Dissent, among other publications. He teaches at Bard College.

  Katherine Harmon is an award-winning freelance writer and contributing editor for Scientific American. Her work covers health, biology, food, the environment, and general-interest stories and has appeared in books, magazines, newspapers, and websites, including Gourmet, Wired, and Nature. Her first book, Octopus! The Most Mysterious Creature in the Sea, will be published this fall. She lives in Longmont, Colorado, with her fiancé and their dog. When not writing or editing, she is likely to be running, gardening, or reading about something nerdy. Read more on her website, www.katherineharmon.com.

  Elizabeth Kolbert is a staff writer for The New Yorker and the author of Field Notes from a Catastrophe: Man, Nature, and Climate Change. Her series on global warming, “The Climate of Man,” from which the book was adapted, won the American Association for the Advancement of Science’s magazine writing award and a National Academies communications award. She is a two-time National Magazine Award winner and has received a Heinz Award and a Lannan Literary Fellowship. Kolbert lives in Williamstown, Massachusetts.

  Alan Lightman is a novelist, essayist, and physicist. He is currently a professor of the practice of the humanities at the Massachusetts Institute of Technology. Lightman’s essays and articles have appeared in Harper’s Magazine, The Atlantic, The New Yorker, and other publications. His novels include Einstein’s Dreams and The Diagnosis, which was a finalist for the National Book Award.

  J.B. MacKinnon is a journalist, essayist, and the author, most recently, of The Once and Future World: Nature As It Was, As It Is, As It Could Be. His book Plenty coined the term “100-mile diet” and is widely recognized as a catalyst of the local food movement. He has lived in the United States, Canada, Spain, and the Dominican Republic.

  Stephen Marche is a novelist and a contributing editor at Esquire.

  Michael Moyer is the special projects editor at Scientific American, the leader of the magazine’s space and physics coverage, and an award-winning science writer. Before he went into journalism, Moyer studied physics and the philosophical foundations of physics at Columbia University and the University of California, Berkeley, and worked as a researcher with the Nobel Prize–winning Supernova Cosmology Project. He lives in New York’s Hudson River Valley with his wife and son.

  Michelle Nijhuis writes about science and the environment for National Geographic, Smithsonian, the New York Times, and many other publications, and she is a longtime contributing editor of High Country News, a magazine that covers environmental issues in the American West. Her work has been recognized with several national honors, including two AAAS Science Journalism Awards, and she is the coeditor of The Science Writers’ Handbook: Everything You Need to Know to Pitch, Publish, and Prosper in the Digital Age. A lapsed biologist, she was once paid to chase tortoises through the Sonoran Desert (the tortoises usually won). She lives with her family in the Columbia River Gorge.

  David Owen has been a staff writer for The New Yorker since 1991. Before joining The New Yorker, he was a contributing editor at The Atlantic and, prior to that, a senior writer at Harper’s Magazine. He is the author of more than a dozen books, including Copies in Seconds, about the invention of the Xerox machine; Green Metropolis, about the environmental value of urban density; and The Conundrum: How Scientific Innovation, Increased Efficiency, and Good Intentions Can Make Our Energy and Climate Problems Worse.

  John Pavlus is a filmmaker and writer interested in science, math, design, technology, and other ways in which people make things make sense. His work has appeared in Scientific American, Wired, Fast Company, Technology Review, and elsewhere. He creates original short films and documentaries, with partners including NPR, Autodesk, the Howard Hughes Medical Institute, and the New York Times Magazine, via his production company, Small Mammal. He lives in Portland, Oregon.

  David Quammen is the author of twelve books, including most recently Spillover: Animal Infections and the Next Human Pandemic, from which “Out of the Wild” is excerpted. As a contributing writer for National Geographic, he travels often, usually to jungles, deserts, savannas, and swamps. In 2012 he received the Stephen Jay Gould Prize from the Society for the Study
of Evolution. He lives in Montana with his wife, Betsy Gaines Quammen, and their menagerie.

  Nathaniel Rich is the author of two novels, Odds Against Tomorrow and The Mayor’s Tongue. His essays and criticism appear in the New York Review of Books, Harper’s Magazine, Rolling Stone, and the New York Times Magazine, among other publications.

  Oliver Sacks is a physician and the author of many books, including The Man Who Mistook His Wife for a Hat, Musicophilia, and Hallucinations. His book Awakenings has inspired a number of dramatic adaptations, including a play by Harold Pinter, an Oscar-nominated film, and a documentary by Bill Morrison with music by Philip Glass. Dr. Sacks is a professor of neurology at the NYU School of Medicine and a visiting professor at Warwick University in the UK.

  Robert M. Sapolsky is a professor of biology and neurology at Stanford University and a research associate with the Institute of Primate Research, National Museum of Kenya. A neuroendocrinologist, he focuses his research on the effects of stress. Two of his books, Why Zebras Don’t Get Ulcers: An Updated Guide to Stress, Stress-Related Disease, and Coping and The Trouble with Testosterone: And Other Essays on the Biology of the Human Predicament, were Los Angeles Times Book Club finalists. He has received numerous honors and awards for his work, including a MacArthur Fellowship and an Alfred P. Sloan Fellowship.