Cognitive performance is characterized by at least two distinct life course trajectories. Many cognitive abilities (e.g. “effortful processing” abilities including fluid reasoning, and processing speed) improve throughout early adolescence and start declining in early adulthood, while other abilities (e.g. “crystallized” abilities like vocabulary breadth) improve throughout adult life, remaining robust even at late ages. Although schooling may impact performance and cognitive “reserve”, it has been argued that these age patterns of cognitive performance are human universals. Here we examine age patterns of cognitive performance among Tsimane forager-horticulturalists of Bolivia, and test whether schooling is related to differences in cognitive performance over the life course to assess models of active vs. passive cognitive reserve. We used a battery of eight tasks to assess a range of latent cognitive traits reflecting attention, processing speed, verbal declarative memory and semantic fluency (n=919 individuals, 49.9% female). Tsimane cognitive abilities show similar age-related differences as observed in industrialized populations: higher throughout adolescence and only slightly lower in later adulthood for semantic fluency, but substantially lower performance beginning in early adulthood for all other abilities. Schooling is associated with greater cognitive abilities at all ages controlling for sex, but has no attenuating effect on cognitive performance in late adulthood, consistent with models of passive cognitive reserve. We interpret the minimal attenuation of semantic fluency late in life in light of evolutionary theories of post-reproductive lifespan, which emphasize indirect fitness contributions of older adults through the transfer of information, labor and food to descendant kin.

Tsimane men show positive associations between testosterone and cognitive performance, particularly for recall and visual scanning, despite higher immune burden. Testosterone may help motivate both physical and cognitive capacities that were essential for extracting the difficult-to-acquire, high-quality resources upon which humans relied over evolutionary history.

Women in Western societies have made enormous gains in education and labor force involvement since the middle of the twentieth century. Various gender differences persist, however. For example, young men and women in the United States continue to differ in their plans for work and family, with women more likely than men to choose careers that will "work around" their family plans (Bridges, 1989). A social constructionist perspective suggests that such differences are the result of societal influences that reinforce traditional gender roles. An evolutionary perspective explains psychological sex differences in work and family priorities as a natural consequence of greater female investment in children over evolutionary history. In the current paper, we test competing predictions about how exposure to college -an environment that encourages gender egalitarianism and individual choice --might moderate the magnitude of male-female differences in work-family plans. We surveyed broad samples of freshmen and seniors enrolled in a public liberal arts university. Sex differences apparent in first-year students' educational aspirations were absent among seniors. However, men and women at both points in college differed sharply in their plans for working when they had young children at home. We discuss our findings in the context of broader concerns about women's status in the workforce.