Journal of Economic Behavior & Organization Vol. 53 (2004) 75–79 Discussion Evolutionary parallelism versus co-evolution: a comment on Joseph Henrich Werner Güth a,* , Hartmut Kliemt b a Max-Plank-Institute for Research into Economic Systems, Strategic Interaction Unit, von Wirtschafts systemen, Wernor Gth Kahlaische Strasse 10, D 07745 Jena, Germany b Philiosophy Department GMU, Duisburg, Germany Received 29 July 2002; accepted 9 December 2002 Accounts of the astonishing extent to which human behavior tends to be unselfish even in anonymous large-scale interaction (see Kropotkin, 1919) have always provoked expla- nations in terms of group interest, group selection and group functions. But since the late sixties the use of such terms has become almost a Lakatosian “do not” (see Lakatos, 1978) among evolutionary theorists. Only recently there have been several attempts to rejuve- nate concepts of group selection in evolutionary biology and beyond (for a discussion that captured broader attention (Sober and Wilson, 1998)). That these attempts now have made their way into economics (see for an overview Bergstrom, 2002) and that they are related to findings from the experimental economics and other empirical literature is a promising development. Joseph Henrich’s paper is a case in point. He is clearly right to insist that the idea of group selection has often been dismissed too lightly on a priori rather than empirical grounds in the past. At the same time Henrich’s criticisms of many approaches to explaining the extent of “pro-social behavior” in human societies are well put. One of us toyed some 20 years ago with the “big mistake hypothesis” (see Kliemt, 1985). The severe difficulties of that hypothesis are clearly laid out by Henrich (in the section on kin based selection). Likewise he evenhandedly evaluates the mixed evidence on the “green beard” signaling mechanism. We have used a related idea of “signaling and detecting commitments” when analyzing trust in large-scale anonymous interactions (see Güth and Kliemt, 2000;Güth, Kliemt and Peleg, 2000). We still believe that Henrich’s criticism does not render our ideas useless. But it is clearly very useful to put economic views in a broader perspective here. In any event, Henrich’s cautionary remarks are well put: In evolutionary settings all depends on the complexities of the situations in which evolution takes place. Bearing this in mind let * Corresponding author.: Tel.: +49-3641-686-620; fax: +49-3641-686-623. E-mail address: gueth@mpiew-jena.mpg.de (W. Güth). 0167-2681/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0167-2681(03)00106-9