Digital Friendships

Those of us who have loads of Facebook friends tend to have greater development in several specific brain regions, says a new study.

"Guys, guys - I just felt my entorhinal cortex triple in size!"

Researchers have found a strong correlation between large numbers of Facebook connections and increased development of gray matter – tissue containing neuron cell bodies, where dense communication occurs – in several regions crucial for social interaction: the amygdala, the right superior temporal sulcus (STS), the left middle temporal gyrus (MTG), and the right entorhinal cortex (EC).

Intriguingly, the size of some of these regions seems to correlate only with the size of people’s online social networks – not their real-world ones. It’s not clear yet, though, which factor is cause and which is effect – whether increased development in these regions enables people to develop larger online social networks, or vice versa. Even so, this is one of the first studies to directly link neuroanatomical data with online behavior.

As the journal Proceedings of the Royal Society B reports, a team led by Geraint Rees at University College London (UCL) performed MRI scans of the brains of 125 university students, and correlated this data with information on the size of these students’ Facebook friend groups:

The number of social contacts declared publicly on a major web-based social networking site was strongly associated with the structure of focal regions of the human brain. Specifically, we found that variation in the number of friends on Facebook strongly and significantly predicted grey matter volume in left MTG, right STS and right entorhinal cortex.

The exact links between these regions and online communication remain to be studied – but many of them have been correlated with social interaction in other studies.

The amygdala helps us process negative emotions like fear and sadness, both in ourselves and others – and people with larger amygdalas tend to have larger social networks overall, both online and otherwise.

Though no studies so far have correlated the size of the right STS with social network size, this structure is known to be involved in our ability to think of some objects as alive, as well as in helping us understand what others are looking at, and what emotions they’re expressing. A malfunctioning STS is thought to be a major factor in autism.

The exact role of the left MTG isn’t precisely understood, but many neuroscientists think this structure is involved in our ability to recognize familiar faces, and to process the semantic associations (i.e., meanings) of words.

The right EC works closely with the hippocampus to help us form and consolidate explicit/declarative memories – i.e., memories of specific facts and events, and specific associations between them (e.g., “kitties and bunnies are both mammals”). The EC is also one of the first areas attacked by Alzheimer’s. The researchers found that this region correlated especially strongly with online friend group size, but not particularly with real-world friend group size:

The right entorhinal cortex is implicated in associative memory formation for pairs of items including pairs of names and faces. Such memory capacity for name–face associates would constitute an important function for maintaining a large social network as observed in social network websites.

In short, the ability to mentally “tag” photos and posts with the correct associations is a central skill for maintaining digital friendships.

It’s easy to see how all the brain regions above could play central roles in a person’s ability to maintain a wide-ranging network of online friends. What’s especially interesting, though, is that all of them deal with features of social interaction that port from the real world to the online interaction space in straightforward ways – social hierarchies, facial expressions, repeatable facts, and so on – but that many other vital aspects of real-world social interaction – such as body language, and tone of voice – don’t appear to be nearly as crucial in an online social network. It’s enough to make you wonder what natural selection may have in store for our brains.

I don’t know about you, but I’m picturing a future where men compete in flame-wars for the right to woo attractive females. So while you my competitors are out hitting the bars and clubs this weekend, I’ll be – ah – honing my skills on 4chan and Reddit. Which is basically what I’d be doing this weekend anyway.

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