Paper short abstract:

In what contexts is it reasonable to infer, when a tree-building approach has been taken to a set of cultures or languages, that the resulting tree is also representative of a bifurcating population history?

Paper long abstract:

In recent years phylogenetic methods have been used to reconstruct historical relationships among languages, and to estimate rates of vertical transmission and of borrowing in the cultural traditions documented by ethnographers. I shall introduce this work, and discuss briefly some of the underlying assumptions about human cultural transmission.

My main purpose in this talk is to question the demographic interpretation which is often proposed or implied when a tree-building approach has been taken to a set of cultures or languages, namely that the resulting tree is also representative of a bifurcating population history.

Firstly, I will ask in what circumstances the attributes of artefacts made by adults display the features taught to them as children, and in what circumstances those attributes reflect the norms and requirements of the community in which the adult has residence.

Secondly, I will describe recent work on language competition and language shift, and ask in what circumstances processes on trees might reflect analogous underlying demographic events. In other words, when does branch pruning on a linguistic phylogeny (language death) reflect local population extinction, and when does it reflect a purely cultural extinction process with the descendants of its speakers simply transferring to a different branch of the language tree (language shift)?