Feedback, punishment and cooperation in public good experiments

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 significantly less cooperation and lower efficiency compared to a treatment in which subjects receive information about the contributions of their peers. This is despite the fact that the feedback format does not affect incentives. The data suggest that this happens because the feedback format acts as a coordination device which influences the contribution standards that groups establish.