We experimentally investigate reference group formation and the impact of social comparisons in a three-player ultimatum game. The players compete in a real-effort task for the role of the proposer. The role of the responder is randomly allocated to one of the other two participants. The third...

A number of studies have shown that peer punishment can sustain cooperation in public good games. This paper shows that the format used to give subjects feedback is critical for the efficacy of punishment. Providing subjects with information about the earnings of their peers leads to...