I develop a game theoretic model where players use two different reasoning processes in strategic situations: cooperative and competitive. Players always consider cooperating at first: if they believe others will cooperate with enough probability, they will do so; otherwise they behave...

We investigate the welfare effect of increasing competition in an anonymous two-sided matching market, where matched pairs play an infinitely repeated Prisoner's Dilemma. Higher matching efficiency is usually considered detrimental as it creates stronger incentives for defection. We point out,...