The number of Facebook friends has been linked to the part of the brain that controls social skills, according to researchers at University College London. Previous tests have shown that people with lots of real-life friends tend to have a more developed amygdala, which is the part of the brain associated with emotional response. But the latest study has found that an enlarged amygdala is also common in people with lots of Facebook friends.
Volunteers placed in a 3-D scanner had bigger, denser structures in three areas of the brain if they had a big list of Facebook friends compared to counterparts who had few online friends, scientists found.
The three locations are all linked with the power to socialise.
'Our findings support the idea most Facebook users use the site to reinforce existing relationships,' says Professor Geraint Rees of the University College of London.
This seems to negate the popular theory that spending lots of time on the internet is bad for relationships and social skills.
The study appeared this week in the journal Proceedings of the Royal Society B, published by Britain's de-facto academy of sciences.
Rees's team enrolled 125 students, 46 of them men, whose average age was 23.
Their Facebook friends varied in number from just several to nearly 1000. Averaged out, this meant around 300 friends per volunteer.
These results were then checked, to monitor for any bias, in a separate sample of 40 volunteers.
The superior temporal sulcus and middle temporal gyrus, "are associated with social perception such as perceiving other people's gaze or social cues from facial expressions", said University College London researcher Ryota Kanai.
The third area, the entorhinal complex, "might be associated with memory for faces and names", he said.
In a third experiment, the scientists looked more closely at a sub-sample of 65 of volunteers to see whether there was a link between the online world and real world in brain structure.
In addition to undergoing brain scan, this group also filled out a questionnaire about their friends in the real world.
Matching the tally of real-world friendships with that of online friendships, the scientists found only one correlation in brain matter.