We define social reciprocity as the act of demonstrating one's disapproval, at some personal cost, for the violation of widely-held norms (e.g., don't free ride). Social reciprocity differs from standard notions of reciprocity because social reciprocators intervene whenever a norm is violated...

Because costly punishment is not credible, subgame perfection suggests that punishment will not deter free riding, regardless of the size or structure of groups. However, experiments show that people will punish free riders, even at considerable cost. To examine the implications of agents who...

Recent experiments show that public goods can be provided at high levels when mutual monitoring and costly punishment are allowed. All these experiments, however, study monitoring and punishment in a setting where all agents can monitor and punish each other (i.e., in a complete network). The...