The seemingly rampant economic selfishness suggested by many recent corporate scandals is at odds with empirical results from behavioural economics, which demonstrate high levels of prosocial behaviour in bilateral interactions and low levels of dishonest behaviour. We design an experimental setting, the ‘Big Robber’ game, where a ‘robber’ can obtain a large personal gain by appropriating the earnings of a large group of ‘victims’. In a large laboratory experiment (N = 640), more than half of all robbers took as much as possible and almost nobody declined to rob. However, the same participants simultaneously displayed standard, predominantly prosocial behaviour in Dictator, Ultimatum and Trust games. Thus, we provide direct empirical evidence showing that individual selfishness in high-impact decisions affecting a large group is compatible with prosociality in bilateral low-stakes interactions. That is, human beings can simultaneously be generous with others and selfish with large groups.

最近许多公司丑闻所暗示的看似猖獗的经济自私与行为经济学的实证结果不一致，行为经济学表明双边互动中的亲社会行为水平较高，不诚实行为水平较低。我们设计了一个实验场景，“大盗”游戏，其中一个“强盗”可以通过挪用一大群“受害者”的收入来获得巨大的个人利益。在一个大型实验室实验中（N = 640），超过一半的劫匪尽可能多地抢夺，几乎没有人拒绝抢劫。然而，同样的参与者在独裁者、最后通牒和信任游戏中同时表现出标准的、主要是亲社会的行为。因此，我们提供了直接的经验证据，表明影响大群体的高影响决策中的个人自私与双边低风险互动中的亲社会性是相容的。也就是说，人类可以同时对他人慷慨，对大群体自私。