Sowing Doubt Optimally in Two-Person Repeated Games

Abstract:

Consider a two-person repeated game (with complete information). Assume that one of the players - say player 1 - has the possibility to sow doubt, in the mind of his opponent, as to what his own (i.e., player 1's) payoffs are. This results in a two-person repeated game with incomplete information. It turns out that, by sowing this kind of doubt, a player can increase his minimal equilibrium payoff in the original game. We prove that this minimum is maximal when only one payoff matrix, which is equal to the negative payoff matrix of the opponent, is added. Thus, it is optimal for a player to make his opponent believe that, with some positive probability, he is playing a zero-sum game. We obtain two formulas for calculating this maximal minimum payoff. Finally, we look at the outcome when both players simultaneously sow doubt in this way.

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