Journal of Economic Behavior & Organization Vol. 65 (2008) 458–471 Evolution of cooperation in a one-shot Prisoner’s Dilemma based on recognition of trustworthy and untrustworthy agents Marco A. Janssen a,b a School of Human Evolution and Social Change, Arizona State University, Box 872402, Tempe, AZ 85287-2402, USA b School of Computing and Informatics, Arizona State University, Box 872402, Tempe, AZ 85287-2402, USA Received 6 July 2004; accepted 16 February 2006 Available online 26 September 2006 Abstract This article explores the conditions under which agents will cooperate in one-shot two-player Prisoner’s Dilemma games if they are able to withdraw from playing the game and can learn to recognize the trustwor- thiness of their opponents. When the agents display a number of symbols and they learn which symbols are important to estimate the trustworthiness of others, agents will evolve who cooperate in games in line with experimental observations. These results are robust to significant levels of mutations and errors made by the players. © 2006 Elsevier B.V. All rights reserved. JEL classification: B52; C70 Keywords: Estimating trustworthiness; Cooperation; One-shot Prisoner’s Dilemma 1. Introduction Several theories have been proposed to explain the evolution of human cooperation. The theory of kin selection focuses on cooperation among individuals who are closely related genet- ically (Hamilton, 1964), whereas theories of direct reciprocity focus on the selfish incentives for cooperation in repeated interactions (Trivers, 1971; Axelrod, 1984). The theories of indirect reciprocity and costly signaling show how cooperation in larger groups can emerge when the cooperators can build a reputation (Alexander, 1987; Nowak and Sigmund, 1998; Lotem et al., E-mail address: Marco.Janssen@asu.edu. 0167-2681/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jebo.2006.02.004