[LINK] Two neuroscience/social networking links

[rfmcdonald]

Perhaps more pseudoneuroscience than anything else.

At the New York Times, Robin Dunbar--creator of the Dunbar's number theory, perhaps discoverer of the principle if it actually exists--talks about how social networking can't change the human brain's capacity for relationships.

Put simply, our minds are not designed to allow us to have more than a very limited number of people in our social world. The emotional and psychological investments that a close relationship requires are considerable, and the emotional capital we have available is limited.

Indeed, no matter what Facebook allows us to do, I have found that most of us can maintain only around 150 meaningful relationships, online and off — what has become known as Dunbar’s number. Yes, you can “friend” 500, 1,000, even 5,000 people with your Facebook page, but all save the core 150 are mere voyeurs looking into your daily life — a fact incorporated into the new social networking site Path, which limits the number of friends you can have to 50.

What’s more, contrary to all the hype and hope, the people in our electronic social worlds are, for most of us, the same people in our offline social worlds. In fact, the average number of friends on Facebook is 120 to 130, just short enough of Dunbar’s number to allow room for grandparents and babies, people too old or too young to have acquired the digital habit.

This isn’t to say that Facebook and its imitators aren’t performing an important, even revolutionary, task — namely, to keep us in touch with our existing friends.

Until relatively recently, almost everyone on earth lived in small, rural, densely interconnected communities, where our 150 friends all knew one another, and everyone’s 150 friends list was everyone else’s.

But the social and economic mobility of the past century has worn away at that interconnectedness. As we move around the country and across continents, we collect disparate pockets of friends, so that our list of 150 consists of a half-dozen subsets of people who barely know of one another’s existence, let alone interact.

The amygdala is big, meanwhile, Wired Science reporting that the size of the amygdala in a human being relates to said being's number of friends.

The researchers measured two social network factors in 58 adults. First, they calculated the size of a participant’s network, which is simply the total number of people who are in regular contact with the participant. Second, they measured the network’s complexity, based on how many different groups a participant’s contacts can be divided into. The authors then examined how well those two factors correlated with the size of a participant’s amygdala and hippocampus. The hippocampus served as a negative control, as it should not vary based on social networks.

Linear regression revealed a positive correlation in amygdala size with both social network size and complexity. This effect showed no lateralization, meaning both left and right amygdala volumes followed this relationship. In addition, the effect is relatively specific, as other social factors like life satisfaction and perceived social support failed to correlate with amygdala volume.

Social network size and complexity did not significantly correspond with the size of the hippocampus or other subcortical areas. The authors did find that three regions in the cerebral cortex of the brain (caudal inferior temporal sulcus, caudal superior frontal gyrus, and subgenual anterior cingulate cortex) might correlate with social networks. They propose that those regions might have evolved along with amygdala to deal with the complexities of growing social circles.

(Too, apparently a thickened amygdala also correlates to conservatism, and a damaged amygdala can reduce or eliminate the human capacity for fear.)

All FYI.