BEE lecture series - Heidi Colleran, Max Planck Institute for Evolutionary Anthropology

The demographic transition to low fertility is one of the most important global phenomena in human history. It raises profound questions for evolutionary theorizing about human reproduction. Despite decades of research, we do not have comprehensive evolutionary theory on why small family size norms have evolved, and whether they can last. Evolutionary / demographic research at the micro-level tends to downplay the role of culture. For cultural evolution researchers, demography is an important focal point, but the micro-level mechanisms generating variable population structures are largely ignored. In this talk I will highlight empirical research that aims to bring these two strands together, using anthropological-demographic data from a sample of 22 rural Polish farming communities undergoing demographic and economic transition. I will describe how micro-level changes in social interactions, education, wealth and contraceptive use all relate to the potential for information transfer, and may scale up to influence the demographic trajectory of a population. I will also outline some broader conceptual issues in the application of evolutionary principles to reproductive behavior. I will argue that a multilevel, coevolutionary approach to these questions can shed new light on the dynamics of fertility in the past, present and future.