(PD) A non-zero-sum game in which both players have incentive not to cooperate under any circumstances.

A particular arrangement of payoffs in a two-person situation in which each individual has to choose between two alternatives without knowing the other's choice. The payoff structure is arranged such that the optimal strategy for each person depends upon whether she can trust the other or not. If trust is possible, the payoffs for each will be considerably higher than if there is no trust.

A non- zero-sum game in which both players have incentive not to cooperate under any circumstances. Thus, the optimal game theory strategy of always defect has the paradoxical property that both players would have a higher payoff if they ignored the advice of game theory.

when the independent pursuit of self-interest by two parties makes both worse off.

a game in which individual incentives lead to a nonoptimal (noncooperative) outcome. If the players can credibly commit to cooperate, then they achieve the best (cooperative) outcome.

A NON-ZERO-SUM game in which both players have the incentive not to cooperate independently, no matter what. But collectively they would be better off if they did cooperate. This tension between individual incentive and collective incentive is what makes the PD intriguing.

A type of dilemma in which one party must make either cooperative or competitive moves in relation to another party; typically designed in such a way that competitive moves are more beneficial to either side, but if both sides make competitive moves, they are both worse off than if they both cooperated.

a situation in which the noncooperative pursuit of self-interest by two parties makes them both worse off