Half-Hearted Cooperation: A Theory of the Evolution of Altruistic Preferences

Abstract

This paper presents an evolutionary model in which altruists and egoists simultaneously survive natural selection. Successive generations of randomly paired agents play a two-stage game consisting first of a choice of technology and second a choice of effort level. This setting induces a form of cooperation if at least one of the pair is an altruist but not when both are egoists. As a result, in the population steady state there is a positive fraction of both types of agent that is a function of the technology and of the altruists’ degree of regard for their opponents.

Keywords: Altruism, Cooperation, Economics and Biology, Evolution of Preferences, Contribution and Free-Riding, Prisoners’ Dilemma, Technology Adoption

JEL Classification: D64, D74, H41, O33, L23