Why Is Reciprocity So Rare in Social Animals? A Protestant Appeal

Summary of: Why Is Reciprocity So Rare in Social Animals? A Protestant Appeal

Author(s) / Editor(s)

Game theoretic explanations of the evolution of cooperation in humans and other animals relies on assumptions -- rational players should never cooperate, cooperative behavior is explained by direct or diffuse reciprocity, animals can do the mental bookkeeping necessary to reciprocate with multiple partners over time -- that are not always or often borne out by data, necessitating new conceptual tools.

Publication Reference

Published in/by
Genetic and Cultural Evolution of Cooperation, Peter Hammerstein, Ed., MIT Press in Cooperation with Dahlem University Press


  • Partner markets, emotions, learning, reputation all strongly influence cooperation in social animals including humans, but are ignored by conventional game theory models of reciprocal altruism, indicating a need for new conceptual tools in evolutionary game theory.
  • Evolution does not design new mental tools for each problem, but modifies existing mechanisms.

Game theoretic explanations of cooperation involving tit-for-tat strategies and reciprocal altruism are not supported by a large body of evidence. Only a small number of animal examples have been found. Simple models of repeated games do not match the circumstances of evolutionary change. Partner switching and mobility counter the assumptions necessary for reciprocal altruism as a stable evolutionary mechanism. Reciprocity requires significant mental machinery – how do organisms determine whether the actions of others are intentionally or unintentionally cooperative or uncooperative? Alternative conceptual schemas such as partner markets – making it unprofitable for partners to switch – offer alternative conceptual schemas. Emotions may play a role in mediating complex interactions in which intentionality and reputation play a part.