Cultural Evolution: Phylogeny versus Reticulation

Cultures, languages, and biological populations evolve in time and space through both phylogenetic processes of transgenerational inheritance and reticulate processes of interaction and borrowing (diffusion). Phylogenetic processes in the human context are set in motion by geographic expansion and especially by population migration into new territories. Long periods of nonmigratory interaction can lead eventually to the erosion of phylogenetic signals, but the circumstances under which erosion occurs can differ between material and social aspects of culture, language, and biology. In general, but restricted to the past few millennia, language families retain the most accessible traces of phylogenetic descent.