Under the Hood

Zapping Specific Part Of Brain May Reduce Aggressive Intentions, Boost Moral Judgment

Brain stimulation was shown to reduce violent tendencies and boost moral judgment in a new study led by researchers at the University of Pennsylvania and the Nanyang Technological University (NTU) in Singapore.

The paper titled “Stimulation of the Prefrontal Cortex Reduces Intentions to Commit Aggression: A Randomized, Double-Blind, Placebo-Controlled, Stratified, Parallel-Group Trial” was published in the Journal of Neuroscience on July 2.

The study tested an electrical brain stimulation technique called transcranial direct-current stimulation (tDCS). It was targeted at a specific part of the human brain (i.e. the dorsolateral prefrontal cortex) which is related to aggression and moral decision-making.

Lead author Olivia Choy, who is an assistant professor of psychology at NTU, explained antisocial individuals tend to have deficits in this region.

“If an offender's brain is scanned, we don't really know if it's the brain deficit that leads to the behavior or if it's the other way around,” she said. “One of the main objectives of this study was to see whether there was a causal role of this brain region on antisocial behavior.”

Choy and the rest of the research team recruited 86 healthy adults for the study. One half of the group, chosen at random, went on to take part in a 20-minute session of tDCS. 

Participants were later provided with two hypothetical scenarios revolving around physical assault (a man smashing a bottle over someone's head for getting too close to his girlfriend) and sexual assault (intimacy turning into date rape). They were asked to rate how likely they would act as the protagonist in such scenarios using a scale of 0 to 10.

Compared to the half that did not receive the treatment, it was found the tDCS participants displayed lesser intention to commit such acts and were more likely to perceive those acts as morally wrong.

“When most people think of crime they think bad neighborhoods, poverty, discrimination, and those are all correct,” said Adrian Raine, a professor of criminology at Penn. “But we also believe that there’s a biological contribution to crime which has been seriously neglected in the past. What this shows is that there could be a new, different approach to try and reduce crime and violence in society.”

However, it is too early to say whether this technique could be used to reduce the potential for aggressive behavior and criminal acts. The study had limitations as it only assessed the short-term effect of the stimulation. It is not yet clear whether the treatment is safe to use for several months or beyond a year.

While it may not be a “magic bullet,” it could potentially become an intervention offered to first-time offenders in the future, according to senior author Roy Hamilton, an associate professor of neurology at Penn. “Perhaps,” he stated in conclusion, “the secret to holding less violence in your heart is to have a properly stimulated mind.”  

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