Lasting reciprocity promotes cooperation

The behavioral strategy allows for mistakes and thus promotes cooperation. Players track the imbalance of cooperation in their repeated interactions. MPI for Evolutionary Biology - Understanding mutual cooperation is a key element in understanding how people work together. Whether it is friends doing favors for each other, animals exchanging food or aid, or nations coordinating policies, these are all essentially cooperative interactions. Such interactions require people to be willing to help others, but also to fight back when they are taken advantage of. But what rules ensure that cooperation can flourish without being exploited? To investigate this question, Charlotte Rossetti and Christian Hilbe from the Max Planck Institute for Evolutionary Biology in Plön, together with collaborators from the Dalian Institute of Technology (China), rely on the so-called repeated prisoner's dilemma. In a repeated prisoner's dilemma, two game players face the same decision at the same time: they can pay a small price to give the other player a financial advantage, or do nothing.