Study: In some games, nice guys do finish first

WASHINGTON — Screaming sports coaches and cutthroat tycoons have it wrong: Nice guys do finish first, a new study suggests.

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 brinkmanship game of "Prisoner's Dilemma." The research appears in the new 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, study author Martin Nowak said. 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 often wound up doomed.

"It's a very positive message," said study co-author David Rand, a Harvard biology graduate student. "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 noncooperative person 40 cents, but the other player had to pay a dime to mete out the punishment.

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, not handing out punishment paid off more in the long run, the study found.