Flexibility and Reputation in Repeated Prisoner's Dilemma Games

We study how three matching institutions, differing in how relationships are dissolved, affect cooperation in a repeated prisoner's dilemma and how cooperation rates are affected by the presence of a reputation mechanism. Although cooperation is theoretically sustainable under all institutions, we show experimentally that cooperation rates are lowest under random matching, highest under fixed matching, and intermediate in a flexible matching institution, where subjects have the option to dissolve relationships. Our results also suggest important interactions between the matching institution and reputation mechanism. Under both the random matching and flexible matching institutions, both subjective (based on subjects' ratings) and objective (based on subjects' actions) reputation mechanisms lead to substantial increases in cooperative behavior. However, under fixed matching, only the subjective reputation mechanism leads to higher cooperation. We argue that these differences are due to different reputation mechanisms being more forgiving of early deviations from cooperation under certain matching institutions, which gives subjects the ability to learn the value of cooperation rather than getting stuck with a bad reputation and, consequently, uncooperative relationships.