Neuroscientists from the University of California have discovered that during quiet moments, our brains prepare us for being socially connected to other people.
In experiments, the researchers showed people photos with captions while tracking their brain activity. In one set of photos, the captions described the mental state of the person depicted, while the captions of the other set merely described the picture. A third set showed the number of the picture accompanied by a mathematical equation.
Participants were then asked to judge whether the captions expressed what the images showed. It turns out that the same areas of the brain (the dorsomedial prefrontal cortex) lit up during the gaps between pictures as when the mental state captions were shown, but became inactive when the equations and descriptions were displayed.
"The brain has a major system that seems predisposed to get us ready to be social in our spare moments," said Matthew Lieberman, a UCLA professor of psychology and of psychiatry and biobehavioral sciences. "The social nature of our brains is biologically based."
He added: "It is getting us ready to see the world socially in terms of other people's thoughts, feelings and goals. That indicates it is important; the brain doesn't just turn systems on. We walk around with our brain trying to reset itself to start thinking about other minds."
That, the authors believe, is why we like reading Facebook during downtime - the brain gets to do what it's programmed to do. Lieberman said: "When I want to take a break from work, the brain network that comes on is the same network we use when we're looking through our Facebook timeline and seeing what our friends are up to."
The study results were published in the Journal of Cognitive Neuroscience.