Earlier this week the legendary biologist Robert Trivers gave a talk, "Why We Lie (even to ourselves)," to a packed auditorium at my school, Stevens Institute of Technology. If you haven't heard of Trivers, you should have. Harvard psychologist Steven Pinker calls him "an underappreciated genius" and "one of the great thinkers in the history of western thought." In the 1970s, when he was a graduate student at Harvard, Trivers wrote a handful of papers that now rank among the most important in the history of biology.

One addressed this question: Why are we kind to each other? And not just to people who share our genes--parents, sisters, brothers, sons, daughters--but to total strangers? Like the Good Samaritan, who helps a man who has been robbed and beaten and left to die in the road. Like a woman who sends her hard-earned money to a charity for starving children. Or a man who jumps in a pond to save someone from drowning.

Biologists call this behavior altruism, when we help someone else at some cost to ourselves. If you think about it, altruism is the basis of all morality. So the larger question is, Why are we moral? In "The Evolution of Reciprocal Altruism," published in 1971, Trivers proposed that natural selection would have bred altruistic impulses into our ancestors if acts of kindness led to a net, tit for tat benefit. The Good Samaritan helps the robbery victim, and he or his family members help the Samaritan in return, propagating his kindly genes.

In subsequent papers, Trivers used evolutionary theory and genetics to explain why families are often seething with conflict. Trivers pointed out that even close relatives, unless they are identical twins, do not share all of each other's genes, and mothers and fathers don't share any genes at all. And so you get hatred and competition as well as love and cooperation between family members. This dark, Darwinian view of the family resembles that of Freud, except based on sound biology rather than hand-wavy speculation.

The theories of Trivers inspired some of the best-known works of modern biology, including blockbusters like The Selfish Gene by Richard Dawkins and Sociobiology by Edward Wilson. Trivers laid the foundation of sociobiology and its offshoot evolutionary psychology, which attempts to understand human thought and behavior in evolutionary terms.

I've been pretty hard on evolutionary psychology. In fact, a recent critique in The New Yorker, which quotes Trivers, repeated complaints in my October 1995 article in Scientific American, "The New Social Darwinists." I've even taken shots at Trivers himself, but I have enormous respect for his achievements. That's why I invited him to give a talk at my school about his new book The Folly of Fools: The Logic of Deceit and Self-Deception, which I reviewed for The New York Times last December.

Deceit is obviously an adaptive trait, which can help us (and many other animals) advance our interests, but why self-deceit? Trivers notes, first, that lying can require a lot of cognitive energy, which results in "tells" such as a higher-pitched voice and sweaty skin. Moreover, as lying has evolved, so has the ability to detect lies. Self-deception may be a response to this escalating arms race of lying and lie-detection. We lie more persuasively if we believe our own lies.

Trivers is a riveting speaker, who prowls around the stage like a predator stalking prey, eyes narrowed, hands stabbing and slicing the air. He riffs and rants like a tough, profane street-corner hipster who just happens to have a Nobel-caliber scientific brain. (Trivers has not won a Nobel but he did win the Crafoord Prize, which ain't too shabby.) Some highlights of his talk:

Trivers displayed a chart showing that the smarter children are, the more likely they are to lie. The data came from an experiment in which children were left in a room with a box. The scientist, before leaving the room, told the kids not to look in the box. Most of the kids peeked in the box after being left alone, and most denied having done so when asked by the scientist. The smarter the kids, the more likely they were to lie. All of the smartest kids lied. (Think about the implications of that finding for a moment.)

To illustrate his claim that we learn to deceive in infancy, Trivers showed a video of a toddler having a full-blown tantrum, screaming and flailing on the floor. When the camera moves behind a wall, so that the boy is no longer visible, and he cannot see the camera-holder, he falls silent. We then see him peeking around the corner of the wall. As soon as he spots the camera-holder, he hurls himself onto the floor and starts wailing again. Alligator tears, my Dad used to call them.

Trivers got the biggest laughs recounting an experiment in which self-described heterosexual males were shown pornographic films while wearing a plethysmograph, which measures swelling of the penis—or "dick," to use the term preferred by Trivers. The subjects were divided into two groups: those who expressed a strong aversion toward male homosexuals and those who had a laissez-faire attitude. Watching films of a man and woman having sex, or two lesbians, all the males became aroused.

When watching a film of two men having sex, however, the laissez-faire and homophobic males had sharply divergent reactions. The former showed an "insignificant increase" in the diameter of their "wood" (another technical term employed by Trivers), whereas the latter became much more tumescent. When asked whether they had become aroused, however, the homophobes denied it. It is not clear, Trivers said, whether the homophobes were lying or self-deceiving.

Trivers strikes me as almost compulsively honest, in ways that can get you in trouble. There was only one point during his lecture when he seemed phony. Summarizing yet another amusing finding from Folly of Fools, he asserted that academic smarty pants are especially prone to self-inflation; one survey found that 94 percent of academics considered themselves to be above average in their fields. "I plead guilty,” Trivers said with a rueful grin. Bob, drop the false modesty. You're not fooling anyone.

Photo from crafoordprize.se

Postscript: I talk about Trivers and self-deception on Bloggingheads.tv with my buddy George Johnson today. http://bloggingheads.tv/videos/11441?in=37:00&out=39:01

Post-postscript: As mentioned above, journalist Anthony Gottleib criticized evolutionary psychology in the September 17 New Yorker. I asked Trivers if he wanted to respond to Gottleib, who quoted Trivers saying in 1977 that "sooner or later, political science, law, economics, psychology, psychiatry, and anthropology will all be branches of sociobiology." Trivers declined my offer, but Robert Lynch and Emily Aronoff, two graduate students in anthropology at Rutgers, sent me their response:

We were disappointed to read Adam Gottlieb’s criticism of the nascent field of evolutionary psychology ("The hubris of evolutionary psychology," September 17th). Gottlieb’s primary criticism seems to be that evolutionary psychologists rely on undergraduates from ‘Western, industrialized countries’ to understand human universals. The irony here is that this is actually true of every other field that Gottlieb lauds, but is hardly true of evolutionary psychology or its sister field of evolutionary anthropology. At our own institution students and professors have been testing hypotheses generated by evolutionary psychologists on a variety of populations, including a particularly strict religious sect in rural Brazil, reindeer herders in Siberia, genealogical data from Iceland going back a millennium, a longitudinal study in Jamaica and various ethnic groups and tribes in east Africa. When is the last time Social Psychology, Political Science or Economic journals published studies testing hypotheses on tribes in rural Brazil?

Gottlieb attempts to undermine the work of Martin Daly and Margot Wilson on child abuse by stepfathers. He asserts that ‘most step parents don’t hurt anyone’ and ‘most children don’t have step parents’ but it does not matter if most step-fathers are nice and don’t abuse their step-children. The point is that the chances of a child being murdered by a stepfather are between 40 and 70 times higher than when they are raised by a biological father. In Daly and Wilson’s study, statistical analysis showed that this extreme bias was expected less than 1 in 1000 cases by chance. Arguing that this does not tell us something useful about the evolved human brain seems perverse, especially when the knowledge serves to warn us of situations with special danger to children.

Gottlieb cites Steven Jay Gould, a paleontologist from New York University, who disdainfully dismisses the idea of studying humans like we study other species. Because of our complex culture and enlarged brains, he claims we are far too complex to be studied like any other species on the planet. Humans are a unique and complicated species; but so too are a colony of leaf cutter ants that incidentally developed agriculture and pesticides for their fungus gardens 50 million years before our own ancestors solved the same problem. What is more certain than our undisputed complexity, however, is the undisputed arrogance of our species.

We are ignorant of many important things regarding the human brain, but there is no other way that it could have come into being except through evolution by natural selection. There is no competing theory that can explain function and it seems obvious that the only way to connect the social ‘so called’ sciences with biology and the natural sciences is through an understanding of natural selection working on human traits, precisely what evolutionary psychology focuses on. Evolutionary psychologists and physical anthropologists are merely using all “tools” at their disposal to reveal the origin of modern humans and the depths of our behavior. And, all the while, it is important to keep in mind one important thing: humans did not descend from apes. We are apes.