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.

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

Experiments using economic games are becoming a major source for the study of human social behavior. These experiments are usually conducted with university students who voluntarily choose to participate. Across the natural and social sciences, there is some concern about how this...

Impersonal exchange is the hallmark of an advanced society. One key institution for impersonal exchange is money, which economic theory considers just a primitive arrangement for monitoring past conduct in society. If so, then a public record of past actions—or memory—supersedes the function...