The restatement of PD is wrong. Try "PDs show that there are some circumstances in which rational self-interest results in worse outcomes for ALL players (than

The restatement of PD is wrong. Try "PDs show that there are some circumstances in which rational self-interest results in worse outcomes for ALL players (than other, say sentimental or irrational strategies.)" So morally-driven or religious people can get better results, even measured selfishly, than fully rational actors. Repeated PDs aren't just mentioned in the literature, they're a staple, there are competitions between strategies/algorithms to determine the repeat PD champ. Tit for tat was an early champ in those competitions, dunno 'bout now. I like the restatement of PD that reverses the result, but it doesn't really contradict the PD conclusion as properly stated above. Just tells us humans have a hard time acting in their own rational self-interest even when they're trying, 'cause irrational 'cause human.