Cooperation in indefinitely repeated helping games: existence and characterization

Experiments that investigate the spontaneous emergence of money in laboratory societies rely on indefinitely repeated helping games with random matching (Camera et al., 2013; Camera and Casari, 2014). An important open issue is the lack of a general proof of existence of an equilibrium capable of supporting the efficient allocation under private monitoring, without money. Here, we fill this gap by offering a general proof as well as by characterizing the efficient non-monetary equilibrium. An application with code to compute the critical equilibrium parameters is provided to facilitate experimental design.