The evolutionarily dominant strategy is commonly called “Tit-for-tat”—basically, cooperate if and only if you expect your opponent to do so.
No, Tit-for-Tat co-operates if and only if the other player co-operated last time. It works only in an iterated Prisoner’s Dilemma, where you have multiple interactions with the same player.
Co-operate if and only if you expect the other player to co-operate (because of reputation, emotional behaviour etc.) is a quite different strategy. Strategies with some reputational or prediction element like this will work in cases where you have a one-shot interaction with each player, but multiple interactions with a community of players.
Strategies where you “commit” yourself to co-operating but only with players who have similarly committed themselves are different yet again, and work on true one-shot dilemmas. These are the “super-rational” strategies. Variants of these (TDT, UDT etc.) avoid the need for explicit commitments, since they always do what they wish they’d committed to doing.
Basically, I think you are mixing up quite different solutions here to the Prisoner’s Dilemma.
EDIT: I see that Wedifrid made much the same points already. Sorry for the repetition.
No, Tit-for-Tat co-operates if and only if the other player co-operated last time. It works only in an iterated Prisoner’s Dilemma, where you have multiple interactions with the same player.
Co-operate if and only if you expect the other player to co-operate (because of reputation, emotional behaviour etc.) is a quite different strategy. Strategies with some reputational or prediction element like this will work in cases where you have a one-shot interaction with each player, but multiple interactions with a community of players.
Strategies where you “commit” yourself to co-operating but only with players who have similarly committed themselves are different yet again, and work on true one-shot dilemmas. These are the “super-rational” strategies. Variants of these (TDT, UDT etc.) avoid the need for explicit commitments, since they always do what they wish they’d committed to doing.
Basically, I think you are mixing up quite different solutions here to the Prisoner’s Dilemma.
EDIT: I see that Wedifrid made much the same points already. Sorry for the repetition.