assurance game

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Game-theoretic structure also known as the stag hunt, deriving from Rousseau's example in A Discourse on Inequality. In an assurance game, it is best for everybody, individually and socially, if all cooperate. But each fears that the others may not play their part and is then motivated to defect. In Rousseau's example, instead of continuing to play a role in the stag hunt, which requires cooperation, individual hunters allow themselves to be distracted by the lesser game of a hare, which can be caught by an individual, each reasoning that they would be worst off of all if they ignored the hare and stood by the cooperative enterprise, while the others let themselves be distracted. Not being sure of the cooperative dispositions of the others, they may themselves rationally defect, and the social and individual optimum is missed. In an assurance game, the cooperative solution is a Nash equilibrium, since nobody can do better for themselves by defecting from it. Nevertheless with enough suspicion of the others, one may maximize expected utility by defecting.

Subjects: Philosophy.

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