Joseph Henrich and Richard McElreath begin their survey of theories of cultural evolution with a striking historical example. They contrast the fate of the Bourke and Wills expedition — an attempt to explore some of the arid areas of inland Australia — with the routine survival of the local aboriginals in exactly the same area. That expedition ended in failure and death, despite the fact that it was well equipped, and despite the fact that those on the expedition were tough (...) and experienced. For survival in such areas depended on accumulated local knowledge. The locals had learned how detoxify seeds before making bread from them, and how to catch the local fish. Bourke and Wills and their companions lacked this local knowledge, and died as a result (Henrich and McElreath 2003). (shrink)

In this paper I argue, first, that human lifeways depend on cognitive capital that has typically been built over many generations. This process of gradual accumulation produces an adaptive fit between human agents and their environments; an adaptive fit that is the result of hidden‐hand, evolutionary mechanisms. To explain distinctive features of human life, we need to understand how cultures evolve. Second, I distinguish a range of different evolutionary models of culture. Third, I argue that none of meme‐based models, dual (...) inheritance models, nor Boyd and Richerson's models fully succeed in explaining this adaptive fit between agent and the world. I then briefly develop an alternative. Finally, I explore (in a preliminary way) constraints on cultural adaptation. The processes of cultural evolution sometimes built a fit between agents and their environment, but they do not always do so. Why is folk medicine, for example, so much less reliable than folk natural history? (shrink)

The cultural norms of traditional societies encourage behavior that is consistent with maximizing reproductive success but those of modern post-demographic transition societies do not. Newson et al (2005) proposed that this might be because interaction between kin is relatively less frequent in modern social networks. Assuming that people’s evaluations of reproductive decisions are influenced by a desire to increase their inclusive fitness, they will be inclined to prefer their kin to make fitness-enhancing choices. Such a preference will encourage the emergence (...) of pronatal cultural norms if social networks are dense with kin. Less pronatal norms will emerge if contact between kin makes up a small proportion of social interactions. This article reports evidence based on role-play studies that supports the assumption of the kin influence hypothesis that evaluations of reproductive decisions are influenced by a desire to increase inclusive fitness. It also presents a cultural evolutionary model demonstrating the long-term effect of declining kin interaction if people are more likely to encourage fitness-enhancing choices when interacting with their kin than with nonrelatives. D 2007 Elsevier Inc. All rights reserved. (shrink)