Both Nature and Nurture: Incorporating Genetic, Developmental, Directed Environments, and Social Learning within a Demographic Micro-Simulation Model

Michael Murphy, London School of Economics and Political Science (LSE)

Socio-demographic characteristics, such as educational status or fertility history are determined in part by inherited and acquired factors. Acquired characteristics depend on parental characteristics, including their patterns of assortative mating. Earlier work has shown that population sizes are very sensitive to intergenerational continuities in fertility. Individuals also shape their own environments according to their acquired characteristics and previous experiences, suggesting that the role of covariability between these variables is important. I implement a micro-simulation model of a Western developed society with intergenerational transmission of characteristics, based on plausible patterns of assortative mating, in which individuals then modify their own environments. The model is a modified version of the Berkeley SOCSIM kinship micro-simulation model originally developed by Professors Wachter and Hammel. I discuss how these findings relate to statistical models that partition variance into genetic and environmental components, and to the increasing similarity of identical twins with age.