Brewer, D. D. (2016). A systematic review of post-marital residence patterns in prehistoric hunter-gatherers. BioRxiv doi: http://dx.doi.org/10.1101/057059.
Background and Rationale: Post-marital residence patterns refer to where a couple lives after marriage, such as near or with husband's kin (patrilocality) or wife's kin (matrilocality). These patterns influence other aspects of social organization and behavior, and potentially reveal key parts of human nature. Since the 1860s, anthropologists have sought to characterize prehistoric hunter-gatherers' post-marital residence patterns by extrapolating from modern hunter-gatherers' and chimpanzees' behavior. For many reasons, these extrapolations are invalid. I summarized direct evidence of residence patterns from prehistoric hunter- gatherers' remains.
Methods: I conducted a systematic review of strontium isotope and mitochondrial DNA (mtDNA) studies of prehistoric hunter-gatherers and extinct hominins. I also carried out a systematic review of the reliability of classifying prehistoric hunter-gatherer individuals by sex. To evaluate assumptions underlying my analyses of residence patterns, I reviewed the ethnographic literature on hunter- gatherers' mortuary practices as represented in the eHRAF World Cultures database.
Results: The archaeologic sites included in my review represent every inhabited continent except Australia, and their dates span almost the last 10,000 years. In the strontium isotope studies, most adults of both sexes were local, and women were slightly more likely to be local than men. Within sites, women and men had similar mtDNA distributions. Women in neighboring, contemporaneous communities had somewhat distinct mtDNA distributions from each other, while the mtDNA distributions of men in the different communities were less distinguishable. The statistical uncertainties for most summaries are fairly large. Taken together, the results indicate the burial communities were mostly endogamous and that exogamous marriages strained toward matrilocality. The very limited research on extinct hominins' residence patterns is consistent with these findings. In addition, there was only a moderate correspondence between morphologic and genetic estimates of sex in adult prehistoric hunter-gatherer individuals. When I corrected for this measurement error or relied on genetic estimates of sex only, the post-marital residence pattern results shifted in the direction of greater matrilocal tendencies. Modern hunter-gatherers' burial practices were consonant with the assumptions underlying my analyses.
Conclusions: Direct evidence from prehistoric hunter-gatherers' remains indicates very different post-marital residence patterns than those extrapolated from modern hunter-gatherers' and chimpanzees' behavior. In prehistoric hunter-gatherer settings, endogamy may be the outcome of humans' long-term mating preferences. Endogamy may have inhibited bacterial sexually transmitted diseases in prehistory and enabled the evolution of altruism in humans.