Your Brain on Facebook:

Your Brain on Facebook: Bigger Social Networks Expand the Size of Neural Networks

Lots of "friends" drive the growth of gray matter in areas linked to processing social information

BRAIN GAIN: A study being published in the Nov. 4 Science finds that areas of a macaque brain involved with processing social information, including the superior temporal sulcus and the amygdala (orange-red areas), have more gray matter when the monkey forms part of a larger group.Image:

A recent study showed that certain brain areas expand in people who have greater numbers of friends on Facebook. This was welcome news for online social network addicts, particularly teenagers: "Mom, I'm not just on Facebook; I'm doing my temporal lobe calisthenics."

There was a problem, though. The study, inProceedings of the Royal Society B, was unable to resolve the question of whether "friending" plumps up the brain areas or whether people with a type of robustness in brain physiology are just natural social butterflies. "Our own previous study onFacebook could only show correlation between social network size and the brain, but we could not determine the direction of causation between social brain regions andsocial network size," notes Ryota Kanai of University College London, one of the researchers on the study.

To resolve that question would have required locking varying size groups of college students in separate rooms for a year or more to see whether larger groups altered brain structure in some way. Such a proposal would never come within a 100-mile radius of the institutional review boards that examine ethical issues related to research studies.

But with the help of a few monkeys in England, teenagers everywhere may now have more ammunition to use against parents. A study published in the November 4 issue of Science studied 23 macaques assigned to live either alone, with a friend or in a groups of from three to seven fellow primates. The upshot: the monkeys in the larger groups had more gray matter in brain areas linked to processing social information (the middle superior temporal sulcus, amygdala and rostral prefrontal cortex, two of which overlap with those reported on in the Proceedings B study).

Also, monkeys on the top of the heap, status-wise, had more social gray stuff: Big Man (Woman) = Bigger Brain. "The superior temporal sulcus or the amygdala are implicated in humans and macaques, suggesting that the brain networks involved in processing social information in humans has evolved from a network that was already performing computations related to social cognition in rhesus macaques," says Jerome Sallet, one of the University of Oxford researchers who performed the study. Sallet also cautions that the tie between Facebook and brain volume may have been caused by other factors such as time spent on the Internet and that some brain regions found by his group were different from those identified as expanding in the Proceedingsresearch.

So what does this all mean? Do the dynamics of modern existence plump the temporal sulcus to send college graduates for a lifetime of highly social or even altruistic endeavors, impelling them to apply directly to Teach for America rather than an internship in the mergers and acquisitions department of a white-shoe Wall Street firm? Maybe not. It is still unclear whether electronic networks have wholly salutary effects on neural networks. A study in the June 2011 Cyberpsychology by researchers at the University of California, Los Angeles, used a novel form of content analysis to examine changes in the moral values communicated by television programming over a 50-year period. Programming for the ages-nine-to-11 set, or tweens, had changed. During the interval from 1967 to 1997 there was an emphasis on community and family values, thereafter the predominant emphasis switched to focusing on fame as the top social norm.