Scaling of Hunter Gatherer Camp Size and Human Sociality

One of the most commonly-observed properties of human settlements, both past and present, is the tendency for larger settlements to display higher population densities. Work in urban science and archaeology suggests this densification pattern reflects an emergent spatial equilibrium where individuals balance movement costs with social interaction benefits, leading to increases in aggregate productivity and social interdependence. In this context, it is perhaps not surprising that the more temporary camps created by mobile hunters and gatherers exhibit a tendency to become less dense with their population size. Here we examine why this difference occurs and consider conditions under which hunter-gatherer groups may transition to sedentism and densification. We investigate the relationship between population and area in mobile hunter-gatherer camps using a dataset, representing a large cross-cultural sample, derived from the ethnographic literature. We present a model based on the interplay between social interactions and scalar stress for the relationship between camp area and group size that describes the observed patterns among mobile hunter-gatherers. The model highlights the tradeoffs between the costs and benefits of proximity and interaction that are common to all human aggregations and specifies the constraints that must be overcome for economies of scale and cooperation to emerge.