It is widely believed that there are neurological limits to the number of personal connections we can maintain as individuals. The number, proposed by British anthropologist Robin Dunbar, is believed to be around 150, although others suggest it could vary from as low as 100 to as high as 230. The relative limit for each individual is, Dunbar believed, limited by the size of their neocortex.
The Dunbar number has largely passed into the mainstream heuristic when it comes to discussions around the size of social networks, and is often used in debates around the perceived value of online social networks that often number significantly higher than 150 people.
Some new research emerging from Oxford University reveals the relative plasticity of our social networking capabilities however. It suggests that people with a large network of friends and strong social skills have bigger social regions of the brain than those with fewer friends.
“We’re interested in how your brain is able to allow you to navigate in complex social environments,” study researcher MaryAnn Noonan, a neuroscientist at Oxford University, said at a news conference. Basically, “how many friends can your brain handle?” Noonan said.
This is important because scientists still don’t fully understand how the brain manages complex human behaviours, such as social interactions, or indeed how conditions such as autism are represented in the brain.
Previous studies of Macaque monkeys reveal that members of the species that live in large social groups have larger social areas of the brain to deal with facial recognition and other complex social tasks.
Noonan, together with colleagues from McGill University, tested whether similar things happened in humans. They tested participants to determine how many social interactions they undertook in the past month in an attempt to gauge the size of their social network.
They found that the participants with a larger social network had larger social areas of the brain than their peers with smaller social networks. This region included the temporal parietal junction, the anterior cingulate cortex and the rostral prefrontal cortex.
“These different brain regions are all singing different songs,” Noonan said. “Networked areas are all singing the same song, and when they’re connected better, they’re singing more harmoniously with each other.”
Interestingly, it also emerged that the social butterflies amongst us also had better equipped white-matter pathways, which connect different regions of the brain. So some folks are literally better equipped neurologically to be social.
Unfortunately, the researchers weren’t able to discover whether it was the behaviour of participants that increased the social capabilities of the brain, or whether the social capabilities of the brain determined the behaviour.
In the previous study into monkey behaviour however, the size of the social network was determined by the researchers, so they were able to pin down that it was in fact the behaviours that were improving the social fitness of the brain.
Obviously this hypothesis would need to be studied to determine how accurate it is, but the inference is clear. Noonan was also at pains to point out that whilst social gadflies may benefit from having larger social areas, that may come at the expense of other parts of the brain.
“If you’re spending a lot of time in social environments using social skills and your brain’s changing, maybe you’re not learning to juggle in your free time or becoming proficient at the piano,” she said. “The brain is just changing and optimizing to reflect your needs, and if that is thriving within a complex social environment, that is what your brain is reflecting.”
So it might be possible to stretch the Dunbar number upwards, but as yet it’s not quite clear how this may affect other parts of your life.