(5 of 10)
In Trivers' model, non-backscratchers (who refuse to play the game) and overt cheaters (who accept favors but never return them) are long-term losers in the evolutionary game. Yet subtle cheaters who pretend to cooperate but do not are winners. As a result, Trivers believes, humans survived by evolving a complex psychology and set of emotions to keep the altruist from being exploited by cheaters: indignation, guilt, gratitude, sympathy and moralism.
Indeed, to sociobiologists deceit is a crucial factor in evolution. Some birds, like the nighthawk, can feign a broken wing to lure predators away from a nest. In some avian species, a female that has been inseminated by a departed male may try to hide the fact, thus tricking a new male into investing his time and resources in offspring—and genes—that are not his. In the long run, however, natural selection sharpens up both the ability to cheat and the ability to detect cheating. Trivers and Dawkins suggest that the need for deceit—and for its detection—may have been responsible for the rapid enlargement of the human brain during the Pleistocene era.
Sociobiologists believe that self-deception is also a product of evolution, simply because a cheater can give a more convincing display of honesty if he lies to himself as well as to his neighbor. Says Zoologist Richard Alexander of the University of Michigan: "Selection has probably worked against the understanding of such selfish motivation becoming a part of human consciousness." Adds Trivers: "The conventional view that natural selection favors nervous systems which produce ever more accurate images of the world must be a very naive view of mental evolution."
Of all sociobiologists, Trivers has been the boldest in applying the gene-based view to humans. In part, that accounts for his rise—in just ten years —from an author of children's texts to a biology guru at age 34. The son of a Foreign Service officer, Trivers entered Harvard on a scholarship in 1961 to study math and prepare for a career as a civil rights lawyer. He was a bright, moody, private person who turned up at all the civil rights demonstrations and student protests. But his marks were so mediocre ("I was more interested in chasing women and the real world than in math") that his Harvard scholarship was canceled and he was turned down after graduation by two law schools.
Abandoning a law career, he took a job writing children's textbooks for the Educational Development Center in Newton, Mass., and while working on an animal volume was struck by a photo of baboons disciplining their young. It looked so much like human parents dealing with their children, recalls Trivers, "that it was possible to imagine language as just so much froth on the ocean, and that there was something else underlying human discipline. It occurred to me that to understand human behavior, it would be very helpful to examine the behavior of other organisms."