The folk theorem predates and grounds Trivers’s reciprocal altruism better than Axelrod’s tit-for-tat.

Evidence

As for expelling asocial individuals, it is frustrating to a game theorist that such matters are so often discussed without any mention of the folk theorem of repeated game theory (Binmore 2005, p. 79), which was proved some twenty years before Robert Trivers wrote on reciprocal altruism. Quoting Axelrod (1984) will not suffice, because the claims Axelrod makes for the strategy tit-for-tat are almost absurdly inflated (Binmore 1998b). The strategy Baumard et al. needed is called the grim strategy. — Nicolas Baumard, A mutualistic approach to morality, 282

Categorization

• SEED: Article angle: ‘the grim strategy’ as the actual game-theoretic backbone of how cooperative groups police free-riders, and why tit-for-tat’s fame is inflated.