Research Press Release

Punishment as a defence mechanism

Nature Communications

August 17, 2011

Evolution can favour antisocial punishment strategies which maintain the status quo reports a paper in this week’s Nature Communications. As opposed to an altruistic act that particularly promotes cooperation, this work suggests that punishment is mostly a self interested tool for protecting oneself against potential competitors.When studying the cooperation in the laboratory, it has been demonstrated that people are willing to incur costs to free-riders, and that this punishment can promote cooperation. The positive role of punishment, however, has recently been challenged experimentally by the existence of antisocial punishment where cooperators are punished.Now David Rand and Martin Nowak explore whether this antisocial punishment can be explained in an evolutionary framework. By creating an evolutionary game theory model which allows all types of punishment, they show that natural selection does not particularly favour punishment of non-cooperators. Instead, evolution leads to substantial amounts of punishment targeted at all three groups within an optional public goods game — cooperators who contribute to the task, defectors who don’t contribute and loners who work alone. They find that punishment does not increase cooperation or lead to greater payoffs, yet there is still an incentive to punish. Indeed once punishment is available their model finds that it is essential for each strategy type within the game to adopt it so as to protect against dominance by those with other strategies that use punishment.Their model also suggests that ultimately punishment is destructive for all parties, with the average payoff being reduced without creating any benefits.In addition to an evolutionary model, this work also presents preliminary experimental evidence collected using the internet. The experimental data support the predictions of the model, and point towards future experiments to further clarify these issues.

DOI:10.1038/ncomms1442 | Original article

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