Monetary theorists have advanced an intriguing notion: we exchange money to make up for a lack of enforcement, when it is difficult to monitor and sanction opportunistic behaviors. We demonstrate that, in fact, monetary equilibrium cannot generally be sustained when monitoring and punishment...

According to theory, money supports trade in a world without enforcement and, in particular, in large societies, where gift-exchange is unsustainable. It is demonstrated that, in fact, monetary equilibrium breaks down in the absence of adequate enforcement institutions and it collapses as...

Monetary theorists have advanced an intriguing notion: we exchange money to make up for a lack of enforcement, when it is difficult to monitor and sanction opportunistic behaviors. We demonstrate that, in fact, monetary equilibrium cannot generally be sustained when monitoring and punishment...

This paper studies contagious equilibrium in infinitely repeated matching games. The innovation is to identify a key statistic of contagious punishment that, used together with a recursive formulation, generates tractable closed-form expressions for continuation payoffs, off equilibrium. This...

We study an infinite-horizon economy with two basic frictions that are typical in monetary models. First, agents’ trading paths cross at most once due to pairwise trade and other meeting obstacles. Second, actions must be compatible with individual incentives due to commitment and enforcement...

In an experiment, a group of strangers was randomly divided in pairs to play a prisoners’ dilemma; this process was indefinitely repeated. Cooperation did not increase when subjects could send public messages amounting to binding promises of future play.

Monetary theorists have advanced an intriguing notion: we exchange money to make up for a lack of enforcement, when it is difficult to monitor and sanction opportunistic behaviors. We demonstrate that, in fact, monetary equilibrium cannot generally be sustained when monitoring and punishment...