Human Life History and Aging
The evolved human life history is unique in several fundamental aspects: 1) a long juvenile development period, 2) an exceptionally long adult lifespan, 3) support of offspring by post-reproductive individuals, 4) male subsidizing of female reproduction by food provisioning, and 5) a large brain and its capacities for learning. It is proposed that these unique features are co-evolved responses to a dietary shift towards high-quality, nutrient-dense, and difficult-to-acquire food resources. High levels of knowledge, skill, coordination, and strength are required to exploit this suite of high-quality, difficult-to-acquire resources humans consume. The attainment of those abilities requires time and a significant commitment to development. This extended learning phase during which productivity is low is compensated by higher productivity during the adult period, and subsidized by an intergenerational flow of food from old to young. Since productivity increases with age, the time investment in skill acquisition and knowledge leads to selection for lowered mortality rates and greater longevity, because the returns on the investments in development occur at older ages. The theoretical and empirical results obtained to date generate a series of hypotheses and new research questions this project is designed to test and answer.
Project description:
"The human life course and the biodemography of aging."
Project description:
"Grandparenting and the evolution of post-menopausal lifespan."
Sharing and Social Networks
The transfer of food among group members is a ubiquitous feature of small-scale forager and forager-agricultural populations. The uniqueness of pervasive sharing among humans, especially among unrelated individuals, has led researchers to evaluate numerous hypotheses about the adaptive functions and patterns of sharing in different ecologies. Debates about the relevance of several contentious evolutionary models-kin selection, reciprocal altruism, tolerated scrounging, and costly signaling-focus primarily on the extent to which individuals exert control over the distribution of foods they acquire, and the extent to which donors receive food or other fitness-enhancing benefits in return for shares given away. Careful multivariate analyses and cross-cultural comparisons of food transfer patterns are necessary tools for assessing aspects of the sexual division of labor, human life history evolution, and the evolution of the family.
