Data from three bargaining games - the Dictator Game, the Ultimatum Game, and the Third-Party Punishment Game - played in 15 societies are presented. The societies range from US undergraduates to Amazonian, Arctic, and African hunter-gatherers. Behaviour within the games varies markedly across...

Why do individuals engage in personally costly, partisan activities that benefit others? If individuals act according to rational self-interest, then partisan activity occurs only when the benefits of that activity exceed its costs. However, laboratory experiments suggest that many people are...