Institute for Advanced Study Astrophysics Seminar

ABSTRACT: The two-player iterated Prisoner's Dilemma game has been used for 30 years to model evolution, especially the emergence of cooperation. But it still holds surprises, even in the simplest case where the game can be modeled as two simple functions on an eight-dimensional cube. Freeman Dyson and I have shown that the game contains extortionate strategies, where a player who knows the secret can extract an 'unfair' advantage over a player who doesn't, especially any simple evolutionary player. When both players know the secret, the game is an ultimatum game, where each player sets the other player's score, and each can enforce cooperation.