Evolutive Equilibrium Selection II: Quantal Response Mechanisms

Abstract: In this paper we develop a model of Evolutive Quantal Response (EQR) mechanisms, and contrast the outcomes with the Quantal Response Equilibria (QRE) as developed by McKelvey and Palfrey(1995). A clear distinction between the two approaches can be noted; EQR is based on a dynamic formulation of individual choice in the context of evolutionary game theory in which games are played repeatedly in populations, and the aim is to determine both the micro-con ̄guration of strategy choices across the population, and the dynamics of the population frequencies of the strategies played. Quantal Response Equilibria focuses on the more traditional aspects of non-co-operative game theory, i.e. on equilibrium in beliefs regarding strategies.We focus attention on an analytical approach which enables closed form solutions to be constructed. We consider the case of all symmetric binary choice games, which will include analysis of all well known generic games in this context, such as Prisoner's dilemma, Stag-Hunt and Pure coordination games.