The Loitering Presence of the Rational ­Actor

Karl Sigmund in American Scientist:

ScreenHunter_01 Nov. 11 15.06 Humans are social animals, and so were their ancestors, for millions of years before the first campfires lighted the night. But only recently have humans come to understand the mathematics of social interactions. The mathematician John von Neumann and the economist Oskar Morgenstern were the first to tackle the subject, in a book they were planning to call A General Theory of Rational Behavior. By the time it was published in 1944, they had changed the title to Game Theory and Economic Behavior, an inspired move. The book postulated, as did all follow-up texts on game theory for generations, that players are rational—that they can figure out the payoff of all possible moves and always choose the most favorable one.

Three decades later, game theory got a new lease on life through the work of biologists William D. Hamilton and John Maynard Smith, who used it to analyze biological interactions, such as fights between members of the same species or parental investment in offspring. This new “evolutionary game theory” was no longer based on axioms of rationality. Anatol Rapoport, one of the pillars of classical game theory, characterized it as “game theory without rationality.” Herbert Gintis was among the first economists attracted by the new field, and when, 10 years ago, I wrote a review of his textbook Game Theory Evolving, I described it as “testimony of the conversion of an economist.” Gintis has not recanted in the meantime—indeed, a second edition of that book just appeared. But a new companion volume, titled The Bounds of Reason, shows that he certainly has not forgotten his upbringing in the orthodox vein.

More here.