Evaluating Trends in Demographic Transitions: Modeling Behavior in Neolithic and Current Contexts

Demographic transitions in our species history signal important changes in the social and economic organization of populations. This presentation examines causal factors that may influence these changes in population size and dynamics in two recent demographic shifts: the Neolithic Demographic Transition (NDT) and the Current Demographic Transition. The first case study focuses on the NDT in the prehistoric American Southwest where it is argued that a combination of favorable climate, the adoption of maize agriculture, and new technology stimulated rapid population growth and shaped social organization. The Village Ecodynamics Project (Kohler et al 2007) models agents situated on the landscape in prehispanic southwest Colorado and evaluates agents’ resource procurement strategies and cultural interactions. The model presented today extends the Village Ecodynamics Project to evaluate the differential success of various resource strategies inherited through vertical transmission in individual households and lineages over a 700 year period. The topic then shifts to examining the Current Demographic Transition. Parental investment depends on many factors such as the condition of parents, the condition and number of offspring, and the environment in which the individuals live. In skilled-based economies such as the United States, it has been suggested there is a trend for higher socio-economic parents to invest more in their children and thus have fewer children than lower socio-economic parents (Kaplan 1996), which may result in the current Demographic Transition. In addition, the Trivers-Willard Hypothesis suggests that high socio-economic status parents should tend to invest more in their children if they are boys, while lower socio-economic status parents should invest more in their children if they are girls. I have created a model that combines both the ideas of Kaplan and the Trivers-Willard hypothesis to compare the total family size of married couples of varying socio-economic status along with the sex of their first-born child. The results are not completely consistent with the current hypotheses, suggesting that more factors must be examined.