Characterization of hunter-gatherer networks and implications for cumulative culture

Social networks in modern societies are highly structured, usuallyinvolving frequent contact with a small number of unrelated`friends'(1). However, contact network structures in traditionalsmall-scale societies, especially hunter-gatherers, are poorlycharacterized. We developed a portable wireless sensing technology(motes) to study within-camp proximity networks among Agta and BaYakahunter-gatherers in fine detail. We show that hunter-gatherer socialnetworks exhibit signs of increased efficiency(2) for potentialinformation exchange. Increased network efficiency is achieved throughinvestment in a few strong links among non-kin `friends' connectingunrelated families. We show that interactions with non-kin appear inchildhood, creating opportunities for collaboration and culturalexchange beyond family at early ages. We also show that strongfriendships are more important than family ties in predicting levels ofshared knowledge among individuals. We hypothesize that efficienttransmission of cumulative culture(3-6) may have shaped human socialnetworks and contributed to our tendency to extend networks beyond kinand form strong non-kin ties.