Behavioural variation in 172 small-scale societies indicates that social learning is the main mode of human adaptation

Proc. R. Soc. B • Vol/Iss. 282(1810) • The Royal Society • • Published In • Pages: ??•
By Mathew, Sarah, Perreault, Charles

Abstract

Inter-group variation is greater in humans than in any other animal, and scholars continue to debate the cause of this diversity. Two competing explanatory models of human variation emphasize either (1) ecological differences and "evoked" culture or (2) population-level effects of cultural transmission. The former emphasizes mechanisms that operate within a single generation, while the latter emphasizes cumulative cultural history operating over many generations. To test these competing models, the authors measured the relative power of ecological variables as compared to culture history to predict behavioral variation in 172 western North American tribes. Culture history is subdivided into culture phylogeny (based on language phylogeny) and spatial distance.

Note

The Western North American Indian dataset provided information on 297 behavioral variables across a variety of domains, including but not limited to: material culture, subsistence, economic organization, settlement pattern, kinship organization, warfare, supernatural beliefs. The environment of the tribes is also described by 133 ecological variables, including altitude, temperature, precipitation, and the presence of 125 species of plants and animals.

Samples

Sample Used Coded Data Comment
Western North American Indian (WNAI) datasetMixedBehavioral, linguistic, and ecological variables

Hypotheses (8)

HypothesisSupported
Behavioral traits will be affected by both cultural history and ecology (5).Supported
Cultural history will have a stronger effect on the probability of a trait being present than ecology (5).Supported
The effect of cultural history will be largely driven by cultural phylogeny, not spatial distance (5).Supported
Cultural history will have a larger effect than ecology in a majority of traits in the categories of technology and material culture, marriage and family organization, economic organization, ceremonies and rituals, supernatural beliefs, kinship system, political organization, warfare, settlement patterns, and sodalities (5).Supported
The effect of ecology will be greater than culture history in a majority of the traits related to subsistence (5).Supported
Cultural phylogeny will be a stronger predictor than ecology for a majority of traits, except for technology and material culture traits (5).Supported
Both cultural phylogeny and ecology will be stronger predictors than spatial distance for a majority of traits in all categories (5).Supported
The effects of cultural phylogeny will tend to decline over time (5).Supported
Documents and Hypotheses Filed By: erik.ringen