Figure 14.11: Sample payoff matrix for a prisoner’s dilemma game On each trial, each player must decide whether to cooperate or defect, without knowing in advance what the other player will do. The payoff to each player depends on the combination of the two players’ decisions. In this example, the possible payoffs to player 1 are shown in the blue portions of the matrix, and the possible payoffs to player 2 are shown in the green portions.