This is what was said:

"It (game theory) assumes actors are more rational than they often are in reality. Even Nash faced this problem when some economists found that real subjects responded differently from Nash's prediction: they followed rules of fairness, not cold, personal calculation (Nassar 1998: 199)"

Yeah, I remember reading that some slightly generous version of tit-for-tat is the most useful tactic in prisoner's dilemma at least if you're playing several rounds.