title: Is Tit-for-Tat the Answer? On the Conclusions Drawn from Axelrod's Tournaments.
abstract: Axelrod's celebrated Prisoner's Dilemma computer tournaments, published in the early 1980s, were designed to find effective ways of acting in everyday interactions with the strategic properties of the iterated Prisoner's Dilemma game. The winner of both tournaments was tit-for-tat, a program that cooperates on the first round and then, on every subsequent round, copies the co-player's choice from the previous round. This has been interpreted as evidence that tit-for-tat is an effective general-purpose strategy. By re-analyzing data from the first tournament and some more recent data, we provide new results suggesting that the efficacy of tit-for-tat is contingent on the design of the tournament, the criterion used to determine success, and the particular values chosen for the Prisoner's Dilemma payoff matrix. We argue that this places in doubt the generality of the results and the policy implications drawn from them.
authors.affiliation: School of Business Administration, Anderson Hall, 900 University Avenue, University of California, Riverside, California 92521-0203, United States of America.
authors.forename: Amnon
authors.initials: A
authors.lastname: Rapoport
authors.affiliation: Lee Business School, University of Nevada, University of Nevada Las Vegas, 4505 Maryland Parkway-Box 456009, Las Vegas, Nevada 89154-6009, United States of America.
authors.forename: Darryl A
authors.initials: DA
authors.lastname: Seale
authors.affiliation: School of Psychology, University of Leicester, Leicester LE1 7RH, United Kingdom.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Colman
mesh_terms: D006801:Humans; D000068956:Prisoner Dilemma