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Michael Ernest

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Extortion and Evolution in the Iterated Prisoner's Dilemma

Nicholas Pippenger
Second Reader(s)
Francis Edward Su


The Prisoner's Dilemma is a two player game where playing rationally leads to a suboptimal outcome for both players. The game is simple to analyze, but when it is played repeatedly, complex dynamics emerge. Recent research has shown the existence of extortionate strategies, which allow one player to win at least as much as the other. When one player plays such a strategy, the other must either decide to take a low payoff, or accede to the extortion, where they earn higher payoff, but their opponent receives a larger share. We investigate what happens when one player uses this strategy against an “evolutionary” player, who makes small changes to her strategy over time to increase her score, and show that there are cases where such a player will not evolve towards the optimal strategy of giving in to extortion.


Extortion and Evolution in the IPD

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