We characterize the class of symmetric two-player games in which tit-for-tat cannot be beaten even by very sophisticated opponents in a repeated game. It turns out to be the class of exact potential games. More generally, there is a class of simple imitation rules that includes tit-for-tat but...

The problem of collective action is usually identified with social dilemmas. A wider notion of the term collective action problem is introduced, as dilemmas are not the only problems to arise in collective action. The article first presents a typology of collective action problems based on...

Both social psychology and experimental economics empirically investigate social dilemmas. However, these two disciplines sometimes use different notions for very similar scenarios. While it is irrelevant for economists whether an experimental public-good game is conceptualised as a take-some or...

We investigate the welfare effect of increasing competition in an anonymous two-sided matching market, where matched pairs play an infinitely repeated Prisoner's Dilemma. Higher matching efficiency is usually considered detrimental as it creates stronger incentives for defection. We point out,...