According to new research, the belief that bullies lash out at others to make themselves feel better may have some truth to it.
Researchers at the University of Chicago found in the new research that unusually aggressive youth may actually gain some enjoyment from inflicting pain.
Videos of people getting hurt were found to trigger flurries of activity in a brain area associted with reward in aggressive youth, the researchers said. Non-aggressive teens had no such brain activity. The researchers measured brain activity using a common brain scanning technique called fMRI.
For aggressive adolescents, seeing someone in pain triggered strong activation in a brain area called the ventral striatum, which responds to pleasurable events, researchers said.
The research shows some aggressive youths’ natural empathetic impulse may be disrupted, said the university’s Jean Decety, who led the research. “This work will help us better understand ways to work with juveniles inclined to aggression and violence,” he added.
The scientists compared adolescent boys with no unusual signs of aggression to eight 16- to 18-year-old boys who had shown disruptive behavior, such as starting a fight, using a weapon or stealing after confronting a victim.
Participants underwent brain scans while watching videos of people having their foot stepped on, having a heavy bowl fall on their hands, or the like. The scanning system was of a widely used type known as functional Magnetic Resonance Imaging (fMRI), which measures brain activity based on where blood is flowing.
Aggressive adolescents showed a “specific and very strong activation” in a brain area called the ventral striatum, known from previous studies to respond to pleasurable events, Decety said. Unlike the control group, he added, the more aggressive youth didn’t activate brain areas involved in self-control, called the medial prefrontal cortex and the temporoparietal junction.
The more normal youth, Decety said, acted similarly to youth in a study released earlier this year, in which his group used scans to show 7- to 12-year-olds are naturally empathetic toward people in pain. The scans showed that when the children saw animations of someone get hurt, the same part of the brain that registered pain when they hurt became active upon seeing someone else hurt, he explained. When they saw someone intentionally hurt, the part of the brain associated with understanding social interaction and moral reasoning became active.
The findings are reported in the current issue of the research journal Biological Psychology.
Source: University of Chicago
