The behavioral ecology of psychological variation: population density, relatedness, and disease

Recent work has documented a wide range of important psychological differences both between and within societies. Multiple explanations have been proposed to understand why such differences exist, including historical philosophies, subsistence methods, social mobility, social class, climatic stresses, and religion. With the growing body of theory and data, some broader questions are becoming pertinent. What are the foundational dimensions of culture? What are the origins of psychological variation between groups? I propose that a behavioral ecological approach, particularly the idea of phenotypic plasticity, can (1) help unite existing explanations, (2) generate novel predictions, and (3) ultimately facilitate the creation of an ecological taxonomy of cultures, from which one might derive a rich set of predictions with respect to psychological variation across human groups. I will focus on relevant work and predictions on the psychological effects of population density, genetic relatedness, and pathogen prevalence.