 Man Versus Nash: An Experiment on the Selfenforcing Nature of Mixed Strategy Equilibrium
 Jason Shachat, J. Todd Swarthouty, Lijia Wei

 #002021 20131014 (published)
 We examine experimentally how humans behave when they play against a computer which implements its part of a mixed strategy Nash equilibrium. We consider two games, one zerosum and another unprofitable with a pure minimax strategy. A minority of subjects' play was consistent with their Nash equilibrium strategy, while a larger percentage of subjects' play was more consistent with different models of play: equiprobable play for the zerosum game, and the minimax strategy in the unprofitable game. We estimate the heterogeneity and dynamics of the subjects' latent mixed strategy sequences via a hidden Markov model. This provides clear results on the identification of the use of pure and mixed strategies and the limiting distribution over strategies. The mixed strategy Nash equilibrium is not selfenforcing except when it coincides with the equal probability mixed strategy, and there is surprising amounts of pure strategy play and clear cycling between the pure strategy states.
 JELCodes: C92, C72, C10
 Keywords: Mixed Strategy, Nash Equilibrium, Experiment, Hidden Markov Model
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