+ This grid simulates an iterated prisoner's dilemma played across a population of cells. + Each cell represents an agent applying a strategy and playing against its immediate + neighbors at every step ("Step"). Depending on the results obtained, a cell may adopt + the strategy of a better-performing neighbor, which causes the distribution of colors + to evolve over successive steps. +
+ ++ For the dilemma to be valid, the order T > R > P > S must hold. But it doesn't prevent you to have fun with those. +
+ ++ In the classic single-shot, two-player prisoner's dilemma, defection is the dominant + strategy: whatever the opponent does, defecting yields a better payoff, so rational + players end up at the mutual-defection outcome (P, P) even though mutual cooperation + (R, R) would leave both better off. This grid nonetheless shows sizable pockets of + cooperation surviving and even spreading. Two features of the setup explain the + difference. First, the game is repeated rather than played once, so strategies such + as Tit-for-Tat or Grim Trigger can punish defection in future rounds, which removes + the incentive to defect that exists in a single, isolated encounter. Second, agents + only interact with their local neighbors and imitate nearby strategies that perform + well, so clusters of cooperators can support each other and outcompete an isolated + defector, even though a defector still beats an individual cooperator in a single + pairwise match. +
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