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...

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...

We study individual behavior of students and workers in an experiment where they repeatedly faced with the same cooperative task. The data show that clerical workers differ from college students in overall cooperation rates, strategies adopted, and use of punishment opportunities. Students...