Conversation and Cooperation in Social Dilemmas

This article presents an analysis of 35 years of published experiments testing decision making in prisoners' dilemmas. The objective is to begin to reconnect the theory and the evidence of rational behavior by accumulating the experience of the laboratory and examining this record for those factors that consistently altered subjects' choices. It is shown that a model of pure self-interest is usually inconsistent with the results of experimental decision making, predicting either the wrong sign, as in the case of monetary stakes, or ignoring influential variables, such as the content of instructions. This incongruity is widest with respect to the role of language in encouraging cooperation.