Explaining cooperation in groups: Testing models of reciprocity and learning

What are the underlying cognitive processes of cooperation in groups? The question is addressed by examining how well a reciprocity model, two learning models, and social value orientation can predict cooperation in two iterated n-person social dilemmas with continuous contributions. In the public goods dilemma, participants repeatedly decided about contributions to one public good. In the social dilemma network, the public good was divided into multiple two-person public goods, thus allowing selective cooperation. In the experiment participants had to search actively for information about other players’ past behaviors on a computerized information board. The reciprocity model was more successful than the competing models in predicting participants’ information search and contributions. As predicted by the reciprocity model, participants cooperated substantially more in the social dilemma network. Cooperation in repeatedly interacting groups seems to be determined more by reciprocity than by reinforcement learning or stable social motivation.