The Effect of a Random Drift on Mixed and Pure Strategies in the Snowdrift Game

The replicator dynamics of players choosing either mixed or pure strategies are usually regarded as equivalent, as long as strategies are played with identical frequencies. In this paper we show that a population of pure strategists can be invaded by mixed strategists in any two-player game with equilibrium coexistence upon the addition of an arbitrarily small amount of noise in the replication process.