Washington, March 20 (IANS) Punishment, a self-destructive human behaviour, evolved out of the drive to dominate and defend ownership, not to promote cooperation, according to a study. Punishment can lead to a downward spiral of retaliation, with destructive outcomes for everybody involved. People with the highest total payoffs do not use costly punishment, said the researchers.

“Put simply, winners don’t punish,” says the study’s co-author David G. Rand of Harvard University.

Findings of the study have been published in the latest issue of the journal Nature.

“Costly punishment” refers to situations where a punisher is willing to incur a cost in order to penalise someone else.

Other researchers have suggested that costly punishment can compel cooperation in one-time interactions where individuals need not worry about reputation or retaliation.

This is a scenario, which Martin A. Nowak, who led the research, found unrealistic, as “most of our interactions are repeated and reputation is always at stake”.

“There’s been a lot of previous work on the use of punishment in cooperation games, but the focus has not been on situations where individuals use punishment in the context of ongoing interactions,” said co-author Anna Dreber.

Dreber, Rand, Nowak, and Drew Fudenberg of Harvard recruited 104 college students to participate in a computer-based Prisoner’s Dilemma game that was extended to include costly punishment along usual options of cooperation and defection.

Pairs of students played the game repeatedly so the interaction between costly punishment and reciprocity could be assessed.

The result: There is a strong negative correlation between individual payoff and the use of costly punishment.

The five top-ranked players never used costly punishment, while players who earned the lowest payoffs tended to punish most often. Winners used a tit-for-tat like strategy while losers used costly punishment.

“Punishment may be a tool for forcing another person to do what you want,” Dreber says. “It might have been for those kinds of dominance situations that the use of punishment has evolved.”

“Our finding has a very positive message: In an extremely competitive setting, the winners are those who resist the temptation to escalate conflicts, while the losers punish and perish,” concludes Nowak.