Persistence of matrilocal post-marital residence across multiple generations in Southern Africa

Factors such as subsistence turnover, warfare or interaction between different groups can be major sources of cultural change in human populations. Global demographic shifts such as the transition to agriculture during the Neolithic and more recently the urbanization and globalization of the 20th century have been major catalysts for cultural change. Here, we test whether cultural traits such as patri/matrilocality and post-natal migration distance persist in the face of social upheaval and gene flow during the past 150 years in post-colonial South Africa. The recent history of South Africa has seen major demographic shifts that resulted in the displacement and forced sedentism of indigenous Khoekhoe and San populations. During the expansion of the colonial frontier, the Khoe-San admixed with European colonists and enslaved individuals from West/Central Africa, Indonesia and South Asia, introducing novel cultural norms. We conducted demographic interviews among Nama and Cederberg communities representing nearly 3,000 individuals across three generations. Despite the history of colonial expansion, and the subsequent incorporation of Khoe-San and Khoe-San descendant communities into colonial society with strong patrilocal norms during the historic period, patrilocality is the least common post-marital residence pattern in our study populations today. Our results suggest that more recent forces of integration into the market economy are likely the primary drivers of change in the cultural traits in our study. An individual’s birthplace had a strong effect on their odds of migration, distance moved, and post-marital residence form. These effects are at least partially explained by the population size of the birthplace. Our results suggest that market factors local to birthplaces are important drivers of residence decisions, although the frequency of matrilocal residence and a geographic and temporal cline in migration and residence patterns also indicate the persistence of some historic Khoe-San cultural traits in contemporary groups.