Imperfect public monitoring with costly punishment - An experimental study∗

This paper experimentally investigates the effects of a costly punishment option on cooperation and social welfare in long, finitely repeated public good contribution games. In a perfect monitoring environment, increasing the severity of the potential punishment monotonically increases both contributions and the average net payoffs of subjects. In a more realistic imperfect monitoring environment, we find a U-shaped relationship between the severity of punishment and average net payoffs. Access to a standard punishment technology in this setting significantly decreases net payoffs, even in the long run. Access to a very severe punishment technology leads to roughly the same payoffs as with no punishment option, as the benefits of increased cooperation offset the social costs of punishing.