Rethinking Reciprocity

Reciprocity theory has a hallowed status in evolutionary social sciences because it provides a way to explain cooperation among un- related individuals. Theorists have created a large body of mathematical work based on the iterated prisoner’s dilemma game that explores which strategies are evolutionarily stable in a range of conditions including when there are behavioral errors. However, there is a mismatch between the vigorous pace of theoretical research and the trickle of empirical studies that have tested predictions generated by the theoretical work. Furthermore, findings from the empirical work on dyadic cooperation in humans deviate from theoretical predictions in important ways. We argue that this discrepancy suggests that the standard theoretical framework is poorly suited to account for key features of the real-world cooperation, and suggest possible avenues that the theoretical exploration of reciprocity needs to take to close the gap between theory and real-world cooperation.