Journal of Economic Behavior & Organization Vol. 53 (2004) 49–51 Discussion Must there be human genes specific to prosocial behavior? Michael D. Cohen * , Robert Axelrod, Rick Riolo School of Information, University of Michigan, 312 West Hall, Ann Arbor, MI 48109-1092, USA Received 28 June 2002; accepted 12 September 2002 Joseph Henrich’s essay on “Cultural group selection ... ” makes many insightful ob- servations about evolutionary models of cooperative behavior. At the same time, we think there are several important points in his presentation that are questionable, and we do not believe he has made the case for one for his key conclusions: that cultural processes have established—in humans alone—genetic traits for forms of behavior such as ingroup altru- ism and punishment of deviants. We first set out our reconstruction of his argument; then we offer commentary on each of its components. Henrich offers a series of five assertions that, in our reading of his essay, provide an outline of this central argument: 1. Two facts worth explaining are that (a) on average, human beings exhibit much higher levels of cooperation than other species, except perhaps prosocial insects; and (b) par- ticular cooperative behavior patterns vary widely among human subgroups. 2. Models seeking to account for these facts strictly from genetic processes are inadequate and unlikely to be sufficiently improved. 3. Therefore, models are needed that bring into focus the interaction between cultural processes and genetic ones. 4. In such models, one can expect group selection dynamics to be powerful and to lead to group selection at the cultural level, as well as the genetic level. 5. In this setting, some groups will have prosocial practices, and in such groups there will be favorable conditions for establishing prosocial genes for such behaviors as “ingroup altruism and punishment [of deviators]” (p. 30). We respond to these five assertions in turn. * Corresponding author. Tel.: +1-734-647-8027; fax: +1-734-764-2475. E-mail addresses: mdc@umich.edu (M.D. Cohen), axe@umich.edu (R. Axelrod), rlriolo@umich.edu (R. Riolo). 0167-2681/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0167-2681(03)00102-1