Eric Schniter: UC Santa Barbara

Collaborative research from the Tsimane Health and Life History Project has investigated whether age profiles of Tsimane skill development are consistent with life history theory predictions about the timing of productivity and reproduction. Life history models suggest that the especially long human lifespan co-evolved with large brains in a foraging niche where survival depends on complex skills requiring a great deal of learning and accumulated experience. We examined a range of essential Tsimane skills including childcare, food and craft production, music performance, and storytelling. Our results show that: (1) most essential skills are acquired prior to first reproduction, then developed further so that their productive returns meet the increasing demands of dependent offspring during adulthood; (2) as post-reproductive adults age beyond years of peak performance, they report developing additional conceptual and procedural proficiency, and, despite greater frailty, are consensually regarded as the most expert (especially in music and storytelling), consistent with their roles as providers and educators. We find that adults have accurate understandings of their skillsets and skill levels –an important awareness for social exchange, comparison, learning, and pedagogy. These findings extend our understanding of the evolved human life history by illustrating how changes in embodied capital and the needs of dependent offspring predict the development of complementary skills and services in a forager-horticulturalist economy.