Nastiness in Groups

This paper provides evidence showing that people are more prone to engage in nasty behavior, malevolently causing financial harm to other people at own costs, when they make decisions in a group context rather than when making choices individually on their own. We establish this behavioral regularity in a series of large-scale experiments among university students, adolescents, and nationally representative samples of adults-more than ten thousand subjects in total. We test several potential mechanisms, and the results suggest that individual nasty inclinations are systematically more likely to affect behavior when decisions are made under the "cover" of a group, that is, in a group decision-context that creates a perception of diffused responsibility.