Brain Structure Linked to Facebook

The number of friends one has on Facebook correlates with the size of certain brain regions—and the number of friends made in real life.

Jef Akst
Oct 18, 2011

Facebook friends photo gridFLICKR, DAN TAYLOR

Though many users of the social networking site Facebook accumulate hundreds or even thousands of “friends,” many of which they’ve never met, the total is indicative of the number of real-world friends the users have, as well as the size of particular brain structures, according to a study published today (October 18) in Proceedings of the Royal Society B.

“Online social networks are massively influential, yet we understand very little about the impact they have on our brains,” Geraint Rees, a Wellcome Trust Senior Clinical Research Fellow at University College London (UCL), said in a press release. “This has led to a lot of unsupported speculation the internet is somehow bad for us.” So he and his colleagues culled Facebook, which boasts more than 800 million active users worldwide, to see what relationships may exist between the social networking site and the...

The team scanned the brains of 165 university students who used Facebook, and tallied the number of Facebook friends and real-life friends for each. The results revealed a strong correlation between the students’ number of Facebook friends and the number of real-world friends, as well as the volume of grey matter in certain brain regions, including the amygdala, which has previously been associated with the size of a person’s network of real-world friends.

Other brain regions that correlated with the size of the Facebook network include the right superior temporal sulcus (involved in the perception of objects as biological), the left middle temporal gyrus (believed to influence the perception of social cues), and the right entorhinal cortex (associated with memory and navigation, such as through social networks), none of which were associated with real-world friendships.

“Our study will help us begin to understand how our interactions with the world are mediated through social networks,” Rees said in a statement. “This should allow us to start asking intelligent questions about the relationship between the internet and the brain—scientific questions, not political ones.”