American Robert Axelrod publishes in Science “The Evolution of Cooperation” or a Prisoner Dilemma tournament open to all scholars: each submitted algorithm can cooperate (cooperate) or defect to the enemy/attack (defect): the winning strategy turns out to be the TIT-FOR-TAT (blow for blow) by Professor Anatol Rapaport from Toronto, the strategy begins by always cooperating until it is attacked, after which it copies blow for blow what the interlocutor does; Other strategies: TIT-FOR-TWO-TATS (forgive the first strike), NAIVE-PROBER (naive investigator: like tit-for-tat but randomly attacks every now and then), REMORSEFUL-PROBER (forgive the opponent’s revenge), GRUDGER (forever avenger), HARRINGTON (the only “bad” strategy that survived past generation 20 but neared extinction around generation 1000), CHEAT (cheaters), ALWAYS-COOPERATE, ALWAYS-DEFECT
