24 October 2011

Scientists mull brain size-Facebook correlation

by Kate Melville

People with more Facebook friends have more grey matter in their brain, but University College London (UCL) scientists aren't sure whether our online social network is driving the changes in the brain, or if people with bigger brains simply have more friends. The new research, appearing in Proceedings of the Royal Society B, adds to the growing body of work that suggests technology may be dramatically changing the way our brains work.

"Online social networks are massively influential, yet we understand very little about the impact they have on our brains. Our study will help us begin to understand how our interactions with the world are mediated through social networks. This should allow us to start asking intelligent questions about the relationship between the internet and the brain," said UCL's Geraint Rees.

Rees and colleagues at the UCL Institute of Cognitive Neuroscience studied brain scans of 125 university students - all active Facebook users - and compared them against the size of the students' network of friends, both online and in the real world.

The researchers found a strong connection between the number of Facebook friends an individual had and the amount of grey matter in several regions of the brain. One of these regions was the amygdala, a region associated with processing memory and emotional responses.

The size of three other regions - the right superior temporal sulcus, the left middle temporal gyrus and the right entorhinal cortex - also correlated with online social networks, but did not appear to correlate with real-world networks.

The superior temporal sulcus plays a role in our ability to perceive a moving object as biological, and structural defects in this region have been identified in some children with autism. The entorhinal cortex, meanwhile, has been linked to memory and navigation - including navigating through online social networks. The middle temporal gyrus has been shown to activate in response to the gaze of others and so is implicated in perception of social cues.

"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 co-researcher Ryota Kanai.

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Source: Wellcome Trust