Cooperation in PD games: Fear, greed, and history of play

The impact of the cardinal relationships among pecuniary payoffs, and of so cial history and reputation, on the choice of strategies in four one-shot P risoner's Dilemma games is experimentally examined. The results suggest tha t normalized payoff values linked to "fear'' and "greed'' are important as predictors of behavior in the PD games. Success in coordinating on the payo ff dominant equilibrium in previous plays of coordination games also increa ses the probability of cooperative play in the PD games. The effect of past play is strongest when individuals are matched repeatedly with the same pe rson in previous play, as contrasted to being matched randomly with another player.