Cooperation among people who are not related to each other is sustained by the availability of punishment devices which … help enforce social norms (Fehr and Gc̃hter, 2002). However, the rationale for costly punishment remains unclear. This … of punishment. We compare two treatments of a public good game, one in which costly punishment reduces the immediate …

punishment, so that they increase overall welfare? We report an experiment in which players can issue non-binding threats to … their actual punishment level. We find that threats increase the level of contributions significantly. Efficiency is … punishment leads to lower threats, cooperation and welfare, restoring them to levels equal to or below the levels attained in the …

bear a higher burden of punishment costs than non-police subjects. When the norm enforcement institution is endogenous, all …

punishment in a social dilemma. Emotional reaction to free-riding incites individuals to apply sanctions when they are available …