Date of Award:

8-2022

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Sociology and Anthropology

Committee Chair(s)

Jacob Freeman

Committee

Jacob Freeman

Committee

David Byers

Committee

Judson Finley

Abstract

Prehistoric populations across North America seem to grow exponentially, with some variation between regions. Archaeologists have explored the differences somewhat, but have not explained the differences or the sustained growth with any reference to what may be going on under the surface in a way that is relevant to all regions. I propose that environmental limits on population are shaped by what populations eat and how they acquire food, and that when populations are large enough to feel the scarcity in their environment, they change their way of life in a way that increases those limits. The model I propose is well-established, and is called the Malthus-Boserup ratcheting model. I mathematically describe the Malthus-Boserup ratcheting model using a fixed population growth rate and an array of changes in environmental limit, both in the amount of change and rate of change (or how quickly my imaginary populations change their way of life). I then simplify my descriptions of these curves using exponential curves, as archaeologists might simplify real population growth curves in much the same way. I compare the models with their exponential descriptions to form expectations for what the values in exponential curves might mean regarding the archaeological record. Despite having set a constant population growth rate, the exponential curves grow at different rates, depending primarily on the amount of change in environmental population limits. I hypothesize that a list of regions assembled in order of largest to smallest change in population limits should match a list of the same regions assembled in order of exponential growth rate. I use tools in R statistical software to describe the population growth curves in four regions using both exponential curves and summed logistic curves. I then arrange the list of regions according to both the growth rate of the exponential curves and the change in the limits found in the logistic curves. The lists do not match, which suggests that, for a variety of reasons, the exponential curves do not adequately describe the underlying Malthus-Boserup ratcheting process. I then compare the models using the Bayesian Information Criterion. Bayesian Information Criterion is an indicator that increases with both the unexplained variation in the dependent variable and the number of explanatory variables used. In this sense, when comparing models describing the same data, lower values suggest either that information retained outweighs a model’s complexity, or a model’s simplicity outweighs the amount of information lost. In all four cases, the information retained in the Malthus-Boserup ratcheting model outweighs the model’s complexity. Furthermore, the summed logistic models have parameters that researchers can interpret beyond simple rates of change.

Share

COinS