Close friendships outside of the family are key to maintaining a group culture that continues to learn and advance, according to a new study published in Nature Human Behaviour.
For example, many unique human traits such as high cognition, cumulative culture, and hyper-cooperation have evolved due to the social organization patterns unique to humans, particularly because of these close non-kin friendships.
“Making friends and having a friendship network is an important human adaptation, one that has helped us develop cumulative culture,” said Dr. Andrea Migliano of University College London (UCL), first author of the study.
For the study, researchers from the Hunter-Gatherer Resilience Project in Anthropology at UCL used wireless tracking technology to map the social interactions of remote hunter-gatherer populations — the Agta hunter-gatherers in the Philippines and the BaYaka hunter-gatherers in the Congo.
According to the researchers, these groups offer the closest existing examples of human lifestyles and social organization, offering vital insights into human evolutionary history.
“What we see in these hunter-gatherer camps is that people have very strong relationships with their friends — and those relationships are as strong as those with family. These friends connect the different households, facilitating the exchange of information and culture. And it is those connections that make a network efficient,” said Migliano.
In order to study the groups’ social interactions, the researchers used devices called mote — a wireless sensing technology worn as an armband that can record the interactions a person has in one day.
The motes recorded all one-on-one interactions at two minute intervals for 15 hours a day over a week in six Agta camps in the Philippines (200 individuals, 7, 210 interactions) and three BaYaka camps in the Congo (132 individuals, 3,397 interactions). With this data, the researchers were able to construct and examine social networks for both groups in unprecedented detail.
The analyses show that randomization of interactions among either close kin or extended family did not improve the efficiency of hunter-gatherer networks. In contrast, randomization of friends (non-kin relationships) greatly reduced efficiency.
The researchers found that increased network efficiency is achieved through investment in a few strong links between non-kin friends connecting unrelated families. They also found that strong friendships are more important than family ties in predicting levels of shared knowledge among individuals.
The researchers also found evidence that friendships began very early in childhood in both populations.
“In contemporary society, we have the technology to expand these social networks, increasing flow of information over much larger numbers of people,” said Migliano.
“This allows humans to co-operate and work together to build wonderful things. Our work illustrates how friendship is one of the secrets to humans’ success as a species.”
Source: University College London