The number of friends a person has on Facebook is an accurate predictor of the amount of grey matter in certain parts of their brain, accorScientists measured the volume of grey matter in 165 adults and looked at the correlation with their number of friends on the social website, Facebook. They found that the more Facebook friends a person had, the larger the volume of their grey matter in several regions of the brain including the amygdala, which is the area responsible for processing memory and emotional responses.
Three other parts of the brain also showed the same trend. These are involved in memory and navigation, perception of social cues, and the ability to recognize a moving object as biological.
The researchers found that the size of an online social network was also an accurate reflection of the number of real-world friends the person had. This suggests social sites such as Facebook are used as a way of keeping in contact with existing friends, rather than for making networks of new virtual friends.
It is not yet clear what is driving the link between brain structure and social network size; people with more grey matter may build larger social networks, alternatively the creation of social networks may affect brain structure.
“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,” said Dr Ryota Kanai, first author of the study.
Read the full paper for free on the Proceedings of the Royal Society B webpage.
Co-author Geraint Rees is a member of the working group for the forthcoming Royal Society policy report Brain Waves: Neuroscience, responsibility and the law.