Estimating Polygyny Rates Among Hunter-Gatherers: A Statistical Model for Historical Source Criticism With a Yamana Case Study

The purpose of this study is to incorporate an evolutionary perspective into the field of ethnohistory. Specifically, I developed a statistical model to estimate the polygyny rate among hunter-gatherers and applied it as a supplementary method of historical source criticism. The records of Reverend Thomas Bridges, who began his research in the late 1850s, are considered the most reliable accounts of the Yamana (Yahgan) people of Tierra del Fuego, South America. However, his records on the practice of polygyny are inconsistent, stating that polygyny was “very general” at times and denying its existence at others. While historical source criticism necessitates efforts to discover new sources, in cases such as that of the Yamana where reliance on inaccurate records by missionaries and travelers of the time is unavoidable, the evaluation and selection of conflicting sources become crucial. Therefore, I attempted to estimate the polygyny rate among the Yamana using a generalized linear mixed model with hunter-gatherer societies as the population. The results suggest that Bridges’s records, particularly those from the early stages of his research, are likely to be unreliable, even when considering Bayesian credible intervals.