T. J. Gaffney

Reviving, reproducing, and revisiting Axelrod’s second tournament

Abstract Direct reciprocity, typically studied using the Iterated Prisoner’s Dilemma ( IPD ), is central to explaining cooperation. In the 1980s Robert Axelrod ran two computer tournaments in which Tit for Tat ( TFT ) emerged as the winner. Yet the archival record is incomplete:...