Why Cheaters Don't Win: A Proof.

Byline: Karin Bennett

Charles Darwin was no slouch. He came up with the idea that a human trait will persist from one generation to the next only if it confers an evolutionary advantage--now a basic tenet of science. But Darwin could never explain, without contradicting his own theory of bloodthirsty survival of the fittest, why early humans ever agreed to cooperate with one another. Last week a team of mathematicians offered a solution that may put this problem to rest.

From the vantage point of the 21st century, cooperation clearly leaves everybody better off. To a cave dweller, though, the most logical choice was to cheat. Consider this dilemma: If my friends and I cooperate to bring down that woolly mammoth, we'll have more to eat. But if I go gathering while they hunt, I'll feast on meat and berries--which gives me an advantage over my buddies. In fact, Princeton mathematician John Nash won a Nobel Prize for proving that, as long as cheaters can see the benefits of cheating, they will remain cheaters and can live off the fat of the land indefinitely. In last week's issue of the journal Science, however, Martin Nowak and Drew Fudenberg of Harvard ...