Good Strategy or Evolutionarily Stable Strategy?
A strategy is an unconscious behavior program, a candidate for natural selection in competition with alternative strategies. The ‘evolutionarily stable strategy’ (ESS) is the result of Maynard Smith’s tailoring of the mathematics of game theory to fit the theory of evolution. Apart from game theory, the other historical antecedent of ESS theory is the genetical concept of frequency-dependent selection. ESS theory is relevant whenever the optimum strategy for an individual depends upon the frequencies of strategies in the population. The best strategy for a male depends upon the distribution of strategies in the population. ESS theory has mainly been developed in the context of intraspecific aggression, but it is much more widely applicable. Fisher used essentially the same idea in his treatments of sex ratios, Batesian mimicry, and sexual selection. Fishers and pirates are hypothetical, as are the ‘hawks’ and ‘doves’ of Maynard Smith’s papers.