Michael Gurven: UCSB Anthropology

This paper lays the groundwork for a theory of time allocation across the life course. It first develops a parametric model of rates of return on time allocated to productive activities as a function of age. The model is based on the idea that strength and skill vary as a function of age, and that return rates for different activities vary as a function of the combination of strength and skills involved in performing those tasks. The model is then extended to explain time allocation to different activities through the life course from childhood to old age. In addition to age effects on efficiency or productivity, the model includes danger and mortality risks, future benefits of learning, relative efficiencies of different family members and joint execution of tasks, as inputs into time allocation decisions. We then apply the model to traditional human subsistence patterns. The model predicts that young children would engage most heavily in low strength/low skill activities, middle-aged adults in high strength/high skill activities, and older adults in low strength/high skill activities. Data on time allocation and productivity among Machiguenga and Piro forager-horticulturalists of southeastern Peru are used to evaluate the model.