“In fact, the fourteen programs submitted in the first round of the tournament embodied a variety of complex strategies. But much to the astonishment of Axelrod and everyone else, the crown went to the simplest strategy of all: TIT FOR TAT. Submitted by psychologist Anatol Rapoport of the University of Toronto, TIT FOR TAT would start out by cooperating on the first move, and from there on out would do exactly what the other program had done on the move before. That is, the TIT FOR TAT strategy incorporated the essence of the carrot and the stick. It was "nice" in the sense that it would never defect first. It was "forgiving" in the sense that it would reward good behavior by cooperating the next time. And yet it was "tough" in the sense that it would punish uncooperative behavior by defecting the next time. Moreover, it was "clear" in the sense that its strategy was so simple that the opposing programs could easily figure out what they were dealing with.

Of course, with only a handful of programs entered in the tournament, there was always the possibility that TIT FOR TAT's success was a fluke. But maybe not. Of the fourteen programs submitted, eight were "nice" and would never defect first. And every one of them easily outperformed the six not-nice rules. So to settle the question Axelrod held a second round of the tournament, specifically inviting people to try to knock TIT FOR TAT off its throne. Sixty-two entrants tried-and TIT FOR TAT won again. The conclusion was inescapable. Nice guys-or more precisely, nice, forgiving, tough, and clear guys-can indeed finish first.”