If you find yourself liking Facebook 'likes' a little too much, blame your nucleus accumbens.

After experimenting with 31 participants, researchers at the Free University of Berlin found out that people who have high levels of activity in the their nucleus accumbens, the part of the brain that gets activated when you receive awards (like sex and food), are more likely to be the people you see addicted to Facebook. The experiment's participants filled out a survey and filmed an interview video, which went up the next day. They were hooked up to brain scanners as 10 anonymous people watched and reviewed their videos. When someone witnessed their video get positive feedback, their nucleus accumbens got more excited. But, the people whose nucleus accumbens got more excited than the other participants were more likely to be active Facebook users. 

“We found that we could predict the intensity of people's Facebook use outside the scanner by looking at their brain's response to positive social feedback inside the scanner,” said Dar Meshi, the lead author of the report. “We found that the more sensitive a person’s nucleus accumbens is to discovering their own reputation is good, specifically in relation to discovering another person’s reputation is good, the more likely they are to have an intense relationship with the Facebook.”

“Essentially, a neurobiological link was made between brain activity for reputation-related social reward and intensity of Facebook use,” Meshi continued.

So, those 'likes' you keep going back to check for after you updated your status? If you're the type with high levels of activity in your nucleus accumbens, the 'likes' will keep you coming back for more, since it fulfills your need for positive affirmation. If you don't get those 'likes' you're looking for, be careful, because you could start feeling a little down.