A new study found that neurological ‘reward centers’ in bullies lit up when they watched injuries occurred.

Using brain scans, this new study says that bullies may enjoy when they cause pain to others.

According to this University of Chicago study, the part of the brain, linked to reward, lit up when an aggressive person watched such videos in which someone hurt another person. However, the same thing didn’t happen when a non-aggressive youth watched that sort of clip.

The study has been published in the current Biological Psychology.

“When watching pain inflicted on others, aggressive adolescent showed very strong and somewhat specific activation of the amygdala and ventral stratum and it showed that they enjoyed watching others in pain,” said Jean Decety, who is a professor in psychology and psychiatry at the University of Chicago.

In this study, the researchers compared eight 16 to 18-year-old boys, who had aggressive conduct disorder, to a group that didn’t have unusual signs of aggression. The participants had to undergo functional magnetic resonance imaging (fMRI) when watching such videos as showed people enduring pain accidentally. The researchers found that in boys with aggressive conduct disorder, the part of the brain linked to reward lit up while watching such videos.