Cultural phylogenetics of the Tupi language family in lowland South America.

Robert S Walker,Søren Wichmann,Thomas Mailund,Curtis J Atkisson,Martin Krkosek

doi:10.1371/journal.pone.0035025

Robert S Walker, Søren Wichmann + Show 3 more

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https://doi.org/10.1371/journal.pone.0035025

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Abstract

BackgroundRecent advances in automated assessment of basic vocabulary lists allow the construction of linguistic phylogenies useful for tracing dynamics of human population expansions, reconstructing ancestral cultures, and modeling transition rates of cultural traits over time.MethodsHere we investigate the Tupi expansion, a widely-dispersed language family in lowland South America, with a distance-based phylogeny based on 40-word vocabulary lists from 48 languages. We coded 11 cultural traits across the diverse Tupi family including traditional warfare patterns, post-marital residence, corporate structure, community size, paternity beliefs, sibling terminology, presence of canoes, tattooing, shamanism, men's houses, and lip plugs.Results/DiscussionThe linguistic phylogeny supports a Tupi homeland in west-central Brazil with subsequent major expansions across much of lowland South America. Consistently, ancestral reconstructions of cultural traits over the linguistic phylogeny suggest that social complexity has tended to decline through time, most notably in the independent emergence of several nomadic hunter-gatherer societies. Estimated rates of cultural change across the Tupi expansion are on the order of only a few changes per 10,000 years, in accord with previous cultural phylogenetic results in other language families around the world, and indicate a conservative nature to much of human culture.

Highlights

As the genomic revolution proceeds to unravel complex phylogenetic relationships in the tree of life [1,2], analogous comparative methods are available to interpret nested patterns of relatedness among the world’s some 7,000 languages [3] and cultures
We found that ancestral reconstructions of fundamental aspects of Tupi culture indicate that cultural complexity has tended to decline through time with more trait losses than trait gains, at least in most of the cultural traits that we sampled
In some cases the loss of cultural complexity may be a direct result of disastrous demographic effects of European colonization which led to the extinction of approximately half of all Amazonian societies and languages and probably well over 90% of the total indigenous population since 1500 AD [65]

Summary

Introduction

As the genomic revolution proceeds to unravel complex phylogenetic relationships in the tree of life [1,2], analogous comparative methods are available to interpret nested patterns of relatedness among the world’s some 7,000 languages [3] and cultures. The processes by which cultural similarities and differences emerge among human societies over time and space have long been a central focus of anthropological inquiry [8,9] and linguistic phylogenies can help reconstruct ancestral histories of cultural traits through the use of evolutionary models of culture change over linguistic phylogenies [10]. The Automated Similarity Judgment Program [27] (ASJP) uses computerized lexical analysis of 40-item basic vocabulary lists to automatically generate distance-based trees for most of the world’s languages families and greatly expands the potential scope of cultural evolution studies. Recent advances in automated assessment of basic vocabulary lists allow the construction of linguistic phylogenies useful for tracing dynamics of human population expansions, reconstructing ancestral cultures, and modeling transition rates of cultural traits over time

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