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.



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

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