Review of R. Mace, C. Holden and S. Shennan (eds), The Evolution of Cultural Diversity: Phylogenetic Approaches
Journal of the Royal Anthropological Society, 13 (2): 227-228 (2007).
This book is probably best described as work in progress, documenting the emergence of a pioneer field. In 1994, Ruth Mace and Mark Pagel originally proposed that phylogenetic comparative methods were essential for testing co-evolutionary hypotheses in cultural and bio-cultural evolution. A decade later, this book represents the state of the art.
If cultures arise from mother cultures by descent with modification, they cannot be considered independent data points. No statistical test of an adaptive hypothesis is valid if the sample includes cultures related in this way. Phylogenetic comparative methods of the kind explored in this book aim to get around this problem by constructing trees specifying ancestral relationships.
How might such trees be constructed? One possibility is to use genetic data. However, humans are an unusually young species with remarkably little genetic variation, so it has proved difficult to succeed with this approach. This book uses linguistic phylogenies because they offer better resolution of sister groups and because linguistic data are available for more groups.
The book is in two parts. The first asks: ‘How tree-like is cultural evolution?’ Transmission might work vertically, horizontally, or in some admixture of the two. Contributors use a range of empirical studies to examine differences in modes of transmission of cultural traits such as Turkmen carpet designs, artefacts from Papua New Guinea, and basket designs from Native California. Individually modifiable traits (such as the Californian basket designs) may spread more by diffusion across populations than by inheritance within them. Despite this, empirical tests of models of migration routes among Austronesians, on the one hand, and Bantu farmers, on the other, support the editors’ fundamental hypothesis that group-level cultural entities including languages are related in a tree-like way.
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Mace, Ruth,Clare J. Holden &Stephen Shennan (eds). The evolution of cultural diversity: a phylogenetic approach. x,291 pp., maps, figs, tables, bibliogr. London: UCL Press, 2005. (cloth)