Reciprocity and Cooperation in Social Dilemmas

Abstract

In computer simulation studies of the prisoner's dilemma conducted by Axelrod (1984), the tit-for-tat (TFT) strategy was found to be most effective. Two important properties of the TFT strategy are based on the reciprocity norm: (1) It is “provocable” and immediately retaliates if the other person defects; and (2) it is “forgiving” and immedicately reciprocates cooperation if the other returns to cooperation after defection. Delay of reciprocity for the two types of TFT properties were varied: immediate versus one trial delay. In two experiments, a single naive subject (undergraduate male student) was led to believe that he was playing a two-person prisoner's dilemma, but he actually played against a programmed strategy. The results of both experiments yielded significant effects for delay of forgiveness: Mean proportion of cooperative choices was greater when cooperative overtures were reciprocated immediately than when they were delayed. Two other properties of TFT, “niceness” and clarity, were also assessed. The results are interpreted in terms of operant conditioning principles and in terms of Osgood's GRIT strategy.