The long-term expansion and recession of human populations.

Over the last 12,000 y, human populations have expanded and transformed critical earth systems. Yet, a key unresolved question in the environmental and social sciences remains: Why did human populations grow and, sometimes, decline in the first place? Our research builds on 20 y of archaeological research studying the deep time dynamics of human populations to propose an explanation for the long-term growth and stability of human populations. Innovations in the productive capacity of populations fuels exponential-like growth over thousands of years; however, innovations saturate over time and, often, may leave populations vulnerable to large recessions in their well-being and population density.

Should I stay or should I go? The emergence of partitioned land use among human foragers.

Taking inspiration from the archaeology of the Texas Coastal Plain (TCP), we develop an ecological theory of population distribution among mobile hunter-gatherers. This theory proposes that, due to the heterogeneity of resources in space and time, foragers create networks of habitats that they access through residential cycling and shared knowledge. The degree of cycling that individuals exhibit in creating networks of habitats, encoded through social relationships, depends on the relative scarcity of resources and fluctuations in those resources.

The diffusion of maize to the southwestern United States and its impact.

Our understanding of the initial period of agriculture in the southwestern United States has been transformed by recent discoveries that establish the presence of maize there by 2100 cal. B.C.