FRIDAY, Nov. 7 (HealthDay News) -- Bullies may actually enjoy the pain they cause others, a new study using brain scans suggests.

The part of the brain associated with reward lights up when an aggressive teen watches a video of someone hurting another person, but not when a non-aggressive youth watches the same clip, according to the University of Chicago study, published in the current Biological Psychology.

"Aggressive adolescents showed a specific and very strong activation of the amygdala and ventral striatum (an area that responds to feeling rewarded) when watching pain inflicted on others, which suggested that they enjoyed watching pain," researcher Jean Decety, a professor in psychology and psychiatry at the University of Chicago, said in a university news release. "Unlike the control group, the youth with conduct disorder did not activate the area of the brain involved in self-regulation (the medial prefrontal cortex and the temporoparietal junction)."

The study compared eight 16- to 18-year-old boys with an aggressive conduct disorder to a group that didn't show unusual signs of aggression. All participants underwent functional magnetic resonance imaging (fMRI) while watching videos in which people endured pain accidentally, such as when a heavy bowl was dropped on their hands, and intentionally, such as when a person stepped on another's foot.

More information

The U.S. Department of Health and Human Services has more about stopping bullying.