X-Message-Number: 33473 From: David Stodolsky <> Subject: Co-Residence Patterns in Hunter-Gatherer Societies Show Uniqu... Date: Sat, 12 Mar 2011 22:32:44 +0100 This article argues that human evolution was a result of group processes. dss http://www.sciencemag.org/content/331/6022/1286 Science 11 March 2011: Vol. 331 no. 6022 pp. 1286-1289 DOI: 10.1126/science.1199071 Contemporary humans exhibit spectacular biological success derived from cumulative culture and cooperation. The origins of these traits may be related to our ancestral group structure. Because humans lived as foragers for 95% of our species' history, we analyzed co-residence patterns among 32 present-day foraging societies (total n = 5067 individuals, mean experienced band size = 28.2 adults). We found that hunter-gatherers display a unique social structure where (i) either sex may disperse or remain in their natal group, (ii) adult brothers and sisters often co-reside, and (iii) most individuals in residential groups are genetically unrelated. These patterns produce large interaction networks of unrelated adults and suggest that inclusive fitness cannot explain extensive cooperation in hunter-gatherer bands. However, large social networks may help to explain why humans evolved capacities for social learning that resulted in cumulative culture. David Stodolsky Skype/Twitter: davidstodolsky Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=33473