title: Risk buffering and resource access shape valuation of out-group strangers.
abstract: Unlike other primates, humans exhibit extensive inter-group tolerance and frequently build relationships with out-group members. Despite its common occurrence, little is known about the conditions leading to out-group relationship building in humans. What are the social and ecological factors promoting valuation of out-group members as potential social partners? Do they differ from those promoting valuation of in-group members? We propose that opportunities for non-local resource access and resource buffering, crucial in the human foraging niche, will increase valuation of out-group strangers. Using survey and experimental data collected among three Bolivian horticultural populations, we find that individuals with fewer non-locally available resources and more information about out-groups demonstrate more generosity toward out-group strangers, but not in-group strangers. The effects are specific to subjective resource access, not objective measures of access, and out-group exposure, not stereotypes. Further, depending on the measure, existing network connections affect both out-group and in-group giving, suggesting that new partnerships from both in-groups and out-groups may bolster one's networks. Our results illustrate how evolved human psychology is sensitive to the costs and benefits of both out-group and in-group relationships, but underscore that the social and ecological factors favoring new relationships with in-group versus out-group strangers may differ.
authors.affiliation: Department of Anthropology, University of California, Santa Barbara, CA 93106-3210, USA.|Department of Human Behavior, Evolution, and Culture, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103 Leipzig, Germany.
authors.forename: Anne C
authors.initials: AC
authors.lastname: Pisor
authors.affiliation: Department of Anthropology, University of California, Santa Barbara, CA 93106-3210, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Gurven
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D012306:Risk; D012919:Social Behavior; D012944:Social Support; D013240:Stereotyping