Oct. 19, 2011 -- Scientists in the U.K. say they have found a strong link between the number of friends people have on Facebook and how "brainy" they are -- namely, the amount of gray matter in particular regions of their brains.
The researchers from University College London (UCL) also discovered that the more friends people have on the social networking site, the more friends they are likely to have in the "real world."
However, writing in the journal Proceedings of the Royal Society B, they stress the study shows an association and not cause and effect. In other words, are people with more gray matter in parts of the brain more social online and off, or did the brain matter change as a result of getting involved in social media?
Geraint Rees, PhD, a Wellcome Trust Senior Clinical Research Fellow at UCL, says in a news release, "It is not possible from the data to say whether having more Facebook friends makes the regions of the brain larger or whether some people are 'hard-wired' to have more friends."
Facebook has more than 750 million users worldwide. The site allows people to keep in touch online with a network of friends, and the size of these networks varies considerably between individuals. While some people may only have a handful of friends, others have hundreds or thousands.
What has been unclear is whether there is any association between the number of friends a person has in cyberspace and the number of their real-life contacts.
There have been anecdotal suggestions that friends acquired through social networking are of a different character than those acquired through real-world social networks and that people may have more of one type of friend than the other.
To investigate further, 125 students from UCL -- all active Facebook users -- underwent magnetic resonance imaging (MRI) brain scans. After scanning, the number of online and offline friends was recorded for each volunteer.
"Typically, the student population we studied had, on average, 300 friends on Facebook," says researcher Ryota Kanai, PhD.
In one of a series of experiments, Rees and colleagues found a strong link between the number of friends a person had in their Facebook account and the amount of gray matter in several regions of the brain.
One of these regions was the amygdala, a part of the brain associated with processing memory and emotional responses. The researchers say that a study published recently showed the volume of gray matter in this area is larger in people with a larger network of real-world friends. They say this remains true for those involved in the study who had a larger network of online friends.
The size of three other regions in the brain also correlated with online social networks, but the researchers found no such link with real-world networks.
Kanai says, "we have found some interesting brain regions that seem to link to the number of friends we have, both 'real' and 'virtual.' The exciting question now is whether these structures change over time. This will help us answer the question of whether the Internet is changing our brains."
The researchers point out that they are not making any judgments about whether the phenomenon of online social networking is beneficial or harmful. They point out that all the students enrolled in the study were healthy individuals, so any such judgment would not have been possible.
Real vs. Virtual
The researchers also examined whether there was a link between the size of a person's online network of friends and their real-world network.
Volunteers were asked a variety of questions, including how many people they sent a text message to in order to mark a celebratory event such as birthday, the number of friends in their address book, and how many people they had in their Facebook directory.
The researchers say that the responses suggest that the size of the volunteers' online networks also related to the size of their real-world networks.
Effect on Brain
"Our findings support the idea that most Facebook users use the site to support their existing social relationships, maintaining or reinforcing these friendships, rather than just creating networks of entirely new, virtual friends," says Rees.
"Our excitement arises from the fact that this shows, of course, that we can use some of the powerful tools in modern neuroscience to address some of the important questions that people are interested in: namely, what are the effects of social networks -- and online social networks in particular -- and how might my brain mediate the participation in those social networks," he says.
John Williams, PhD, head of neuroscience and mental health at the Wellcome Trust, an organization that partly funded the research, says in a statement, "This new study illustrates how well-designed investigations can help us begin to understand whether or not our brains are evolving as they adapt to the challenges posed by social media."