Hunter-gatherer social networks and the evolution of cooperation


Wednesdays@NICO Seminar, Noon, November 28, Chambers Hall, Lower Level

Prof. Coren Apicella, 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. 


Coren Apicella is an Assistant Professor of Psychology at the University of Pennsylvania interested in understanding the evolutionary origins of human behavior. Much of her research takes place on the African savanna where she studies one of the world's last remaining hunter-gatherer populations. She has published on numerous topics including mate selection and attraction, behavior genetics, behavioral endocrinology, sex differences, behavioral economics and most recently, social networks and the evolution of cooperation. Her research has been featured in media outlets worldwide, including BBCCNNNightline and The New York Times.