Facebook may be changing people's brains as well as their social world, research has shown.
Scientists have found a direct link between the number of Facebook friends a person has and the size of specific parts of the brain.
The regions involved have roles in social interaction as well as memory and at least one is implicated in autism.
It could be that the differences seen are due to the effects of online activity on the brain.
Alternatively, people with certain brain traits may be more likely to have larger numbers of friends, both on Facebook and in the real world.
“We’ve found interesting brain regions that seem to link to the number of friends we have — both ‘real' and ‘virtual',” said Dr Ryota Kanai, one of the researchers from University College London.
“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.”