Wednesday, November 28, 2012
12:00 PM - 1:00 PM
Where: Chambers Hall, Lower Level, 600 Foster St, Evanston, IL 60208 map it
Audience: Faculty/Staff - Student - Public
Coren Apicella, Asst. Professor, University of Pennsylvania
While the evolution of cooperation still remains a puzzle, theorists generally agree that sustained cooperation requires assortative interactions. Yet, little work has examined social networks in relation to cooperation and even less work has investigated it in small-scale societies, despite their importance in understanding human evolution. Here we characterize the social network of the Hadza, an isolated and evolutionarily-relevant population of hunter-gatherers living in Northern Tanzania. We show that Hadza residential camps exhibit high between-group and low within-group variation in cooperative behavior. Moreover, we show that network ties are more likely between people who give the same amount, and this similarity in cooperative behavior extends up to two degrees of separation. Finally, social distance appears to be just as important as genetic relatedness and physical proximity in explaining assortativity in cooperation. Our results suggest that early humans may have formed ties with both kin and non-kin based, in part, on their tendency to cooperate; and that social networks may have contributed to the emergence of cooperation.