A strategic foundation for the cooperator's advantage

Orbell and Dawes develop a non-game theoretic heuristic that yields a 'cooperator's advantage' by allowing players to project "their own 'cooperate-defect' choices onto potential partners'' (1991, p. 515). With appropriate parameter values their heuristic yields a cooperative environment, but the cooperation "depends, simply, on optimism about others' behavior'' (1991, p. 526). In earlier work, Dawes (1989) established a statistical foundation for such optimism. In this paper, I adapt some of the concerns of Dawes (1989) and develop a game theoretic model based on a modification of the Harsanyi structure of games with incomplete information (1967-1968). I show that the commonly made conjecture that strategic play is incompatible with cooperation and the cooperator's advantage is false.