Unilateral commitment in the finitely repeated prisoners' dilemma

In this paper, we modify the finitely repeated prisoners' dilemma by adding an initial round in which the players have the option of simultaneously, u nilaterally and publicly committing themselves, in an enforceable way, to a subset of their strategies. We show that when a large enough number of rep etitions of the prisoners' dilemma follow this initial commitment round, th en not only do the players have incentives to commit themselves to a limite d strategy set, but there is also a symmetric subgame perfect equilibrium i n which both players act cooperatively throughout the post-commitment stage s of the game.