A small study done by researchers at the University of Chicago shows that adolescents with “conduct disorders” – bullies in essence – may be neurologically hardwired to enjoy inflicting pain and suffering upon others.

The study was done on sixteen 18-year-old boys, eight of which were bullies, and eight with no history of unusual aggression. The boys were hooked up to a functional Magnetic Resonance Imaging (fMRI) device and were subjected to video clips of people suffering pain, such as a person with a piano lead being slammed on their hands while playing.

It was noted that in the case of the aggressive youths, seeing the material caused a surge of activity in the areas of the brain linked with feelings of reward, more specifically the amygdala and the ventral striatum. Unlike the control group of regular boys, the bullies showed no activation in the areas of the brain that have to do with self-regulation and restraint, the medial prefrontal cortex and the tempoparietal junction.

The same type of research has been used by the University of Chicago to show that 7-to-12 year old children are naturally empathic to people in pain.

Of the current research, scientists have said that "this work will help us better understand ways to work with juveniles inclined to aggression and violence."

Dr. Michael Eslea, senior lecturer in psychology at the University of Central Lancashire, who was not involved with the study said that while the research was interesting, it needed to be scaled up to a larger sample.

"A better understanding of the biological basis of these things is good to have,” he said, “but the danger is it causes people to leap to biological solutions - drugs - rather than other behavioral solutions."