Generalized Stable Population and Agent-Based Models of phenotypic transmission in human populations, with an application to body size.

We show that generalizations of stable population (GSPM) and agent based models (ABM) are useful tools to simulate the trajectory of a human phenotype. Although mathematically very different, both classes of models can simultaneously account for multiple determinants of the population distribution of a phenotype across time and space. These include genetic transmission, assortative mating, differential fertility, vertical and horizontal cultural heredity, gene-environments interactions (GxE), and environmental feedback. In principle, these models are generalizable to handle selection, drift as well as interactions of these and the other determinants. We illustrate with an application to obesity, a condition that has spread rapidly around the globe increasing the risk of adult chronic illnesses and mortality everywhere. If properly anchored on robust empirical estimates of model inputs, the models' results reproduce well observed trends of the phenotype and can be used as guides for policy interventions.