Cultural phylogenetics in lowland South America

Comparative phylogenetic analyses based on linguistic data are useful for reconstructing the cultural evolution of recent expansions of humans around the world. It is an exciting time for phylogenetic comparative studies in lowland South America given the emergence of more comprehensive ethnolinguistic datasets. Phylogenetic methods can now be applied to more lowland language families to facilitate the study of pre-historical population expansions and cultural variation. This chapter investigates phylogenetic relationships among the six major lowland South American language families using structural linguistic data. Two cultural traits that are likely to have deep evolutionary histories that extend back to last common ancestors of several large language families include uxorilocal postmarital residence (women continue to live near natal families after marriage) and partible paternity beliefs (conception belief that multiple men can be co-genitors of one child). The Carib-Pano-Tupi-Jê clade is mostly uxorilocal with partible paternity beliefs in thirty-eight of forty-three societies.

Quantifying uncertainty in the phylogenetics of Australian numeral systems

Researchers have long been interested in the evolution of culture and the ways in which change in cultural systems can be reconstructed and tracked. Within the realm of language, these questions are increasingly investigated with Bayesian phylogenetic methods. However, such work in cultural phylogenetics could be improved by more explicit quantification of reconstruction and transition probabilities. We apply such methods to numerals in the languages of Australia. As a large phylogeny with almost universal ‘low-limit' systems, Australian languages are ideal for investigating numeral change over time. We reconstruct the most likely extent of the system at the root and use that information to explore the ways numerals evolve. We show that these systems do not increment serially, but most commonly vary their upper limits between 3 and 5. While there is evidence for rapid system elaboration beyond the lower limits, languages lose numerals as well as gain them. We investigate the ways larger numerals build on smaller bases, and show that there is a general tendency to both gain and replace 4 by combining 2 + 2 (rather than inventing a new unanalysable word ‘four'). We develop a series of methods for quantifying and visualizing the results.