It’s not uncommon for someone who works at a computer all day to become distracted. In fact, 53 percent of people in 2011 said they wasted at least an hour at work every day because they were distracted, and for many, Facebook is the distraction of choice. While many of us might not like to admit it, there’s a reason why Facebook is the first thing we go to when we’re looking for that break from our work. According to a new study, the resting brain — or one that’s in need of rest — automatically switches to a region responsible for being social.

The brain is always working, even when we’re not engaged in any sort of tasks. Researchers have known this since at least the 1990s; however, they didn’t know the purpose of all the activity. In their experiments, researchers from the University of California, Los Angeles, found these “major” systems became active “to get us ready to be social in our spare moments,” said Matthew Lieberman, a professor of psychology, psychiatry, and biobehavioral sciences at UCLA, in a press release. “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 researchers found activity in the brain increased in certain regions only when the brain was resting, and that these regions prepared people for picking up on social cues, such as another person’s facial expressions. They discovered this after presenting participants with 40 photographs of people, each containing a caption indicating their mental state — “He is feeling bored” and “She is expressing self-doubt,” for example. Participants were asked to judge whether the captions accurately represented what was happening in the images.

With the help of functional magnetic resonance imaging (fMRI), the researchers saw that the same regions active during a resting period between showing the photos remained active while they considered the mental state of the people in the images. In contrast, when two other sets of the images were presented with different captions — one set of captions described the people’s actions while the other simply had mathematical equations — activity in these areas dropped.

The brain scans also showed that sometimes, when the brain was resting, an area of the brain called the dorsomedial prefrontal cortex became active. When this happened, the participants were able to judge the photos “significantly faster,” but only when the next photo contained a caption about the person’s mental state. There wasn’t any activity in this brain region when the captions were about the person’s actions or mathematical equations.

“It is getting us ready to see the world socially in terms of other people’s thoughts, feelings, and goals,” Lieberman said. “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.” For this reason, he said, we often check social media sites like Facebook when we need a break from work.

Aside from giving us a biological reason for getting distracted with Facebook, the findings could help people who have difficulty reading social cues. Future studies will delve deeper into how these brain regions work, and could uncover ways in which people with these difficulties could practice their social skills.

Source: Spunt R, Meyer M, Lieberman M. The Default Mode of Human Brain Function Primes the Intentional Stance. Journal of Cognitive Neuroscience. 2015.