Introduction

Evolutionary game theory made its way into the social sciences through a curiously circuitous path. Its origin lay in the realization that the mathematical theory of games developed by von Neumann and Morgenstern (1944) could be used to analyze problems of population biology. Because the fitness of an organism (or a trait) in a population often depends on the relative frequency of other organisms (or traits) present, natural selection can take on a strategic character even when none of the organisms are “rational” in any standard sense.

Although modern evolutionary game theory is typically considered to have begun in the work of Maynard Smith and Price (1973), important precursors exist in the work of R. A. Fisher as early as 1930. In The Genetical Theory of Natural Selection, Fisher sought to explain the approximate equality of the sex ratio in mammals using arguments which can be readily understood in game-theoretic terms. The watershed moment for evolutionary game theory, though, was the publication of Maynard Smith's seminal work Evolution and the Theory of Games in 1982. In that text, Maynard Smith drew together a number of results, both from his own work and that of a number of mathematical biologists, presenting them in a clear, coherent format with minimal mathematical prerequisites.

Over time, economists and other social scientists became interested in evolutionary game theory for a variety of reasons, some stemming from long-standing issues in the traditional theory of games. Of these, perhaps the two most important were as follows: first, as von Neumann and Morgenstern clearly recognized, their theory lacked any underlying dynamics. Early on in Theory of Games and Economic Behaviour, they wrote:

Second, the traditional solution concept – that of a Nash equilibrium (which shall be defined below) – suffered from the problem that it was not necessarily unique: games could, and frequently did, have multiple solutions, each of which had some claim to be the “rational” solution.