In human societies, altruistic behaviour can evolve because those who fail to co-operate are lumbered with a bad reputation. This study explores the circumstances under which punishment is favoured using a game theory model in which all individuals observe the interactions between others and assess their reputation under various social norms. It is shown that punishment is only a successful strategy under a narrow set of parameters, including the relative costs of punishment and cooperation, the reliability of reputations and the spread of gossip.
- Hisashi Ohtsuki
- Yoh Iwasa
- Martin A. Nowak
