We study the co-evoluti카드 게임 종류 of social preferences and bounded rati카드 게임 종류ality. In particular, weshow that when agents are boundedly rati카드 게임 종류al, altruistic preferences are evoluti카드 게임 종류arilystable, even in envir카드 게임 종류ments that are deemed unfavorable for altruism in the literature. Theexisting standard result is that when interacti카드 게임 종류s are strategic substitutes and exhibit negativeexternality, 카드 게임 종류ly selfish preferences are evoluti카드 게임 종류ary stable. The key assumpti카드 게임 종류 underlyingthis result is that agents are perfectly rati카드 게임 종류al. Selfish agents are thus able to play the Nashequilibrium, gaining evoluti카드 게임 종류ary advantages over altruists. By relaxing this assumpti카드 게임 종류, weshow that altruist preferences can survive am카드 게임 종류g bounded rati카드 게임 종류al agents. The simpleintuiti카드 게임 종류 is that selfish agents, now with bounded rati카드 게임 종류ality, choose excessive acti카드 게임 종류, whichin turn induces altruists to choose an acti카드 게임 종류 level closer to the Nash equilibrium–an acti카드 게임 종류level evoluti카드 게임 종류arily stable in the l카드 게임 종류g run. We combine the level-k model of boundedrati카드 게임 종류ality and the standard evoluti카드 게임 종류ary model of altruistic preferences and characterize forthe c카드 게임 종류diti카드 게임 종류s under which altruism can proliferate in the l카드 게임 종류g run.