The Evolution of Cooperation provides valuable insights into the age-old question of whether unforced cooperation is ever possible. Widely praised and much-discussed, this classic book explores how cooperation can emerge in a world of self-seeking egoists-whether superpowers, businesses, or individuals-when there is no central authority to police their actions. The problem of cooperation is central to many different fields. Robert Axelrod recounts the famous computer tournaments in which the “cooperative” program Tit for Tat recorded its stunning victories, explains its application to a broad spectrum of subjects, and suggests how readers can both apply cooperative principles to their own lives and teach cooperative principles to others.

pay to be as greedy as JOSS was. A major lesson of this tournament is the importance of minimizing echo effects in an environment of mutual power. When a single defection can set off a long string of recriminations and counterrecriminations, both sides suffer. A sophisticated analysis of choice must go at least three levels deep to take account of these echo effects. The first level of analysis is the direct effect of a choice. This is easy, since a defection always earns more than a cooperation.

part of the country, but from someone who might mount a challenge in the home district. Thus 112 How to Choose Effectively there is not much point in begrudging a fellow legislator the success that comes from mutual cooperation. Likewise in business. A firm that buys from a supplier can expect that a successful relationship will earn profit for the supplier as well as the buyer. There is no point in being envious of the supplier's profit. Any attempt to reduce it through an uncooperative

are not nice. In the round robin tournament, this is not enough to do very well since NYDEGGER often gets in trouble with the other rules which are not nice. In the territorial system, things work differently. By getting five of the rules which are not nice to apologize, NYDEGGER wins a great many converts from its neighbors. When one of these apologizers is next to NYDEGGER and the other three neighbors are nice rules, NYDEGGER is likely to do better than any of its four neighbors or even any of

large enough chance of meeting again and that they do not discount the significance of their next meeting too greatly. For example. what made cooperation possible in the trench warfare of World War I was the fact that the same small units from opposite sides of noman's-land would be in contact for long periods of time, so that if one side broke the tacit understandings, then the other side could retaliate against the same unit. Finally, the evolution of cooperation requires that suc174 The

always defecting after that. In that case, your best strategy is never to defect, provided that the temptation to defect on the first move will eventually be more than compensated for by the long-term disadvantage of getting nothing but the punishment, P, rather than the reward, R, on future moves. This will be true whenever the discount parameter, w, is sufficiently great. s Thus, whether or not you should cooperate, even on the first move, depends on the strategy being used by the other player.