5.8 Darwinian evolution and phylogenetic trees of language and socio-cultural evolution.

The model of Darwinian evolution has become increasingly influential in explaining cultural development and change. In biology researchers have for a long time estimated descent relationships by means of phylogenetic tree-building and by establishing network of relationships between related species. These methods have also been adapted to reconstruct cultural histories. Cultural histories are discerned from deeper signals of historical branching or division derived from the earliest phases of a cultural group’s origin. The branching of culture and the diffusion of cultural traits are the two major determinants that explain the cultural diversity we observe today. Cultural macro-evolution refer to the historical processes that produced variability between cultures in turn created by repeated copying of cultural practices with some modification over time (Felsenstein, 2004; Mesoudi, Whiten, & Laland, 2006). Darwinian analysis has been successfully applied in several disciplines including cultural anthropology, evolutionary archeology, and is equally valid for an interpretation of historical linguistics.

The stability of cultural traits is an important theoretical area to consider in cultural evolution. Modifiability of cultural traits is essential for evolution to occur in response to selective pressures in a population. However, stability of traits occurs when these cultural factors have proven useful to social and ecological adaptation. How do cultures select certain behaviors and how do these cultural traits become stable or lead to changes in the cultural repertoire? Animal behavior evolves because genetic and behavioral traits contribute to the survival of the species (Wynne-Edwards, 1962). Phylogenetic mathematical models have been developed that describe natural selection processes within genes in the individual but is also useful to understand cultural evolution at the group level (Price, 1970). Group selection of a cultural trait occurs when it provides a selective advantage and therefore contributes to the evolution of cultural traits beneficial to the group.

The early development of agriculture in China several thousands of years ago produced many culturally evolutionary gains from the invention of the plow, to developing tools for grain threshing, and eventually by building canals to bring the surplus grain to market. These culturally evolutionary developments produced great advantages to the Chinese state, and created an integrated empire long before these developments occurred in Europe or elsewhere. The evolution of cultural traits associated with agriculture increased the competitive fitness of China compared to other cultures and led to centuries of dominance. Boyd and Richerson (2010) suggested that group selection of genetic traits only occurs when groups are very small and there is little chance of mating and a flow of genes between groups. In other words group selection of genetic traits only has selective advantages for small and geographically distant groups. However, for cultural evolution the example of China shows that although cultural traits benefitting society may develop in small isolated groups with the right social structure cultural traits can be rapidly diffused over a large area.