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 The Harvard University study involved 100 Boston-area college students playing the same game over and over
-- a punishment-heavy version of the classic one-on-one brinksmanship game of prisoner's dilemma. The research appears in Thursday's edition of the journal Nature.
Common game theory has held that punishment makes two equals cooperate. But when people compete in repeated games, punishment fails to deliver, said study author Martin Nowak. He is director of the evolutionary dynamics lab at Harvard where the study was conducted.
"On the individual level, we find that those who use punishments are the losers," Nowak said his experiments found.
Those who escalate the conflict very often wound up doomed.
"It's a very positive message," said study co-author David Rand, a Harvard biology graduate student researcher. "In general, the thing that is most, sort of, rational and best for your own self-interest is to be nice."
The study looked at games between equals. Punishment does seem to have a place in games when one player is dominant and needs to enforce submission, Nowak said.
In Nowak's experiment, the students played more than 8,000 games of prisoner's dilemma, using dimes to reward and punish. The normal game of prisoner's dilemma gives two players two options: cooperate or defect. If both cooperate, each ends up winning a dime. If both defect, each gets nothing. If one cooperates and the other defects, the cooperative player loses 20 cents and the defector wins 30 cents.
Nowak then added a "costly punishment" component. A player could choose to punish someone who didn't cooperate. That penalized the non-cooperative person 40 cents, but the other player had to pay a dime to mete out the punishment.
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 When Nowak compared how much money people earned or lost in the long run, there was a noticeable correlation between punishment and overall money. The players who punished their opponents the least, or not at all, made the most money.
Those who punished the most made the least money.
When faced with a nasty opponent, turning the other cheek and continuing to cooperate
-- or at least not handing out punishment -- paid off more in the long run, the study found.
The paper makes sense and is interesting in its look at repeated interaction, said University of Central Florida economics professor Elisabet Rutstrom, who works on game theory but was not part of the Harvard study.
Nowak said he next wants to study chief executives to see if the findings play out in the real world.
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On the Net:
Nature: http://www.nature.com/nature/
Play prisoner's dilemma (without Nowak's costly punishment) against a computer:
http://www.princeton.edu/~mdaniels/PD/PD.html
[Associated
Press; By SETH BORENSTEIN]
Copyright 2008 The Associated
Press. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
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