http://www.scientificamerican.com/articl...n-facebook
Quote: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, in Proceedings 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 on Facebook could only show correlation between social network size and the brain, but we could not determine the direction of causation between social brain regions and social network size," notes Ryota Kanai of University College London, one of the researchers on the study.