According to the Grandmother and Cooperative Childcare models, female kin-bonded coalitions were pivotal in the evolution of human mutual mindreading, cognition and prosociality. Mothers of increasingly large-brained babies gained fitness benefits from the reliable support of their own mothers. Grandmothers took on a role not only of foraging and care for weaned children but also in transmission of cultural knowledge.
Among historic matrilineal and matrilocal hunter-farmer Bantu speakers, we find sororal groups at the heart of village organisation. By comparing their sociopolitical features with immediate-return, egalitarian African hunter-gatherers, we can show significant time-depth to networks of this kind. They were critical in control of male labour through brideservice, associated with mother-in-law avoidance for men as a ritual sanction, and elaborate female initiation. Controlled by women, this ensured recruitment of the daughter generation. There are marked symbolic similarities between hunter-gatherer and farmer cosmologies, but also some difference in respect of the most tabooed signal: menstruation. We trace this back to early ritual traditions of Homo sapiens.
