The Iterated Prisoner's Dilemma

This is a "primer " on how to play the iterated Prisoner's Dilemma game effectively. Existing research approaches offer the participant limited help in understanding how to cope effectively with such interactipns. To gain a deeper understanding of how to be effective in such a partially competitive and partially cooperative environment, a computer tournament was conducted for the iterated Prisoner's Dilemma. Decision rules were submitted by entrants who were recruited primarily from experts in game theory from a variety ofdisciplines: psychology, political science,economics, sociology,and mathema-tics. The results of the tournament demonstrate that there are subtle reasons for a n in-dividualistic pragmatist to cooperate a s long as the other side does, to be somewhat for-giving, and to be optimistic about the other side's responsiveness