Cultural transmission vectors of essential knowledge and skills among Tsimane forager-farmers

Humans transmit cultural information to others in a variety of ways that can affect productivity, cultural success, and ultimately fitness. Not all potential transmitters are expected to be equally preferred by learners or equally willing to influence their culture acquisition. Across socioeconomic opportunities and ages in the human life course, costs and benefits to both learners and potential transmitters are expected to vary, affecting rates of culture transmission from different vectors. Here we examine reported patterns of culture transmission contributing to 92 essential skills among a sample of 421 Tsimane forager-farmers native to Bolivia. Consistent with the expectation that the costly provision of support and cultural information typically flows from older to younger generations in a subsistence society, we find that the development of essential knowledge and skills is primarily influenced by older same-sex relatives, especially parents. Grandparents are more often reported as transmitters for low-strength/high-difficulty skills that they have comparative advantage in, such as storytelling and musical performance. Though less frequent, same generation peers are more likely to provide discouragement in the learning process and to transmit modern, market-oriented skills. Our findings suggest that kinship, gender, generational seniority, and skill type together explain the vectors and styles of influence responsible for essential culture transmission. The multigenerational pedagogy documented here helps facilitate successful economic and social production in a complex skills niche dependent on multigenerational cooperation, such as observed in human hunter-gatherers and other subsistence populations.