Demography

Law and economics

Free rider problem

Stochastic game

Punishment (psychology)

Public good

Microeconomics

Social psychology

Economics

Public goods game

Psychology

Repeated game

Altruism (biology)

Population

Sociology

Evolutionary game theory

Game theory

Strong reciprocity

Proceedings of the National Academy of Sciences

How did human cooperation evolve? Recent evidence shows that many people are willing to engage in altruistic punishment, voluntarily paying a cost to punish noncooperators. Although this behavior helps to explain how cooperation can persist, it creates an important puzzle. If altruistic punishment provides benefits to nonpunishers and is costly to punishers, then how could it evolve? Drawing on recent insights from voluntary public goods games, I present a simple evolutionary model in which altruistic punishers can enter and will always come to dominate a population of contributors, defectors, and nonparticipants. The model suggests that the cycle of strategies in voluntary public goods games does not persist in the presence of punishment strategies. It also suggests that punishment can only enforce payoff-improving strategies, contrary to a widely cited “folk theorem” result that suggests that punishment can allow the evolution of any strategy.

Altruistic punishment and the origin of cooperation