Why Modeling Cultural Evolution Is Still Such a Challenge. Dan Sperber and Nicolas Claidière. Biological Theory 2006 1(1): 20-22.The idea that cultural evolution exhibits variation, competition, and inheritance and therefore can be studied by adjusting the Darwinian theory of evolution by natural selection is an attractive one. It has been argued by a number of authors (e.g., Campbell 1960; Monod 1970; Dawkins 1976; Cavalli-Sforza and Feldman 1981; Boyd and Richerson 1985; Durham 1991; Aunger 2002; Mesoudi et al. 2004) and pursued in a variety of ways, some (Dawkins and memeticists) staying close to the Darwinian model, others (e.g., Boyd, Richerson, and their collaborators) being more innovative. We agree that there are relevant analogies between biological and cultural evolution and, in particular, that cultural items do exhibit variation, competition, and cumulative modification. On the other hand, we believe that a proper understanding of the mechanisms of cultural propagation drawing on the work of cognitive and social scientists (see Sperber and Hirschfeld 1999 for a review) contradicts the idea that culture exhibits inheritance in the strict sense needed for the theory of evolution by natural selection to apply straightforwardly to it. If so, it will take more than adjusting the Darwinian model to be faithful to the Darwinian inspiration.