ABSTRACT
The Prisoner's Dilemma Game (PDG) is widely used in game-theory experiments to investigate the emergence of cooperative behavior (Rapoport & Chammah, 1965). The payoff table for this game is presented in Table 1. The players simultaneously choose their moves – C (cooperate) or D (defect). Rapoport and Chammah (1965) introduced the quantity CI = (R-P)/(T-S), called cooperation index. It varies between 0.1 and 0.9 and is positively correlated with probability of C choices.
