We study cooperation in economies of indefinite duration. Participants faced a sequence of prisonerʼs dilemmas with anonymous opponents. We identify and characterize the strategies employed at the individual level. We report that (i) grim trigger does not describe well individual play and there...

Does monitoring past conduct facilitate intertemporal cooperation? We designed an experiment characterized by strategic uncertainty and multiple equilibria where coordinating on the efficient outcome is a challenge. Participants, interacting anonymously in a group, could pay a cost either to...

This study reveals the existence of a causal link between the availability of money and an expanded scale of interaction. We constructed an experiment where participants chose the group size, either a low-value partnership or a high-value group of strangers, and then faced an intertemporal...

Social norms of cooperation are studied under several forms of communication. In an experiment, strangers could make public statements before playing a prisoner's dilemma. The interaction was repeated indefinitely, which generated multiple equilibria. Communication could be used as a tool to...

Under what conditions can cooperation be sustained in a network of strangers? Here we study the role of institutions and uncover a new behavioral foundation for the use of monetary systems. In an experiment, anonymous subjects could cooperate or defect in bilateral random encounters. This...

Does monitoring past conduct facilitate intertemporal cooperation? We designed an experiment characterized by strategic uncertainty and multiple equilibria where coordinating on the efficient outcome is a challenge. Participants, interacting anonymously in a group, could pay a cost either to...

Every two person repeated game of symmetric incomplete information, in which the signals sent at each stage to both players are identical and generated by a state and moves dependent probability distribution on a given finite alphabet, has an equilibrium payoff

Markov perfection has become the usual solution concept to determine the non-cooperative equilibrium in a dynamic game. However, Markov perfection is a stronger solution concept than subgame perfection: Markov perfection rules out any cooperation in a repeated prisoners' dilemma game because the...

We consider dynamic group formation in repeated n-person prisonerʼs dilemma. Agreements in coalitional bargaining are self-binding in that they are supported as subgame perfect equilibria of repeated games. Individuals are allowed to renegotiate the cooperating group agreement through a process...

Belief models capable of detecting 2- to 5-period patterns in repeated games by matching the current historical context to similar realizations of past play are presented. The models are implemented in a cognitive framework, ACT-R, and vary in how they implement similarity-based...