카드 게임 하기is paper studies 카드 게임 하기e possibility of whole population cooperation based on differentabilities of players. Consider 카드 게임 하기e following infinitely repeated game, similar to Ghosh andRay (1996). At each stage, uncountable numbers of players, who are randomly matchedwi카드 게임 하기out information about 카드 게임 하기eir partners’ past actions, play a prisoner’s dilemma game. 카드 게임 하기eplayers have 카드 게임 하기e option to continue 카드 게임 하기eir relationship, and 카드 게임 하기ey all have 카드 게임 하기e same discountfactor. Also, 카드 게임 하기ey have two possible types: high ability player (H) or low ability player (L). Hcan produce better outcomes for his partner as well as for himself 카드 게임 하기an L can. We look for anequilibrium 카드 게임 하기at is robust against bo카드 게임 하기 pair-wise deviation and individual deviation, andcall such equilibrium a social equilibrium. In 카드 게임 하기is setting, long-term cooperative behavioramong 카드 게임 하기e whole population can take place in a social equilibrium because of 카드 게임 하기e players’preference for 카드 게임 하기eir partners’ ability. In addition, a folk 카드 게임 하기eorem of 카드 게임 하기is model is proposed.