title: Behavioural variation in 172 small-scale societies indicates that social learning is the main mode of human adaptation.
abstract: The behavioural variation among human societies is vast and unmatched in the animal world. It is unclear whether this variation is due to variation in the ecological environment or to differences in cultural traditions. Underlying this debate is a more fundamental question: is the richness of humans' behavioural repertoire due to non-cultural mechanisms, such as causal reasoning, inventiveness, reaction norms, trial-and-error learning and evoked culture, or is it due to the population-level dynamics of cultural transmission? Here, we measure the relative contribution of environment and cultural history in explaining the behavioural variation of 172 Native American tribes at the time of European contact. We find that the effect of cultural history is typically larger than that of environment. Behaviours also persist over millennia within cultural lineages. This indicates that human behaviour is not predominantly determined by single-generation adaptive responses, contra theories that emphasize non-cultural mechanisms as determinants of human behaviour. Rather, the main mode of human adaptation is social learning mechanisms that operate over multiple generations.
authors.affiliation: School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA Institute of Human Origins, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Mathew
authors.affiliation: School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA Institute of Human Origins, Arizona State University, Tempe, AZ 85287, USA cperreault@asu.edu.
authors.forename: Charles
authors.initials: C
authors.lastname: Perreault
mesh_terms: D002170:Canada; D003468:Cultural Evolution; D004777:Environment; D006801:Humans; D007198:Indians, North American; D000067570:Social Learning; D014481:United States
keywords: cognitive niche hypothesis; cultural evolution; cultural inertia; evoked culture; human behavioural ecology; social learning