The brains of people with large numbers of Facebook friends are different from those of people with fewer online connections, say neuroscientists.The researchers at University College London found that users with the greatest number of friends on the social networking site had more grey matter in brain regions linked to social skills. The finding suggests that either social networking changes these brain regions, or that people born with these kinds of brains behave differently on websites like Facebook.
http://www.guardian.co.uk/science/2011/oct/19/facebook-friend-differences-brain-structureAlso see:More Facebook friends linked to bigger brain areas
Scientists have found a direct link between the number of “friends” a person has on Facebook and the size of certain brain regions, raising the possibility that using online social networks might change our brains.The four brain areas involved are known to play a role in memory, emotional responses and social interactions.
http://in.reuters.com/article/2011/10/19/idINIndia-59975920111019