Brain Stimulation Technique Reduces People's Intent to Commit Violent Acts by More Than Half

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Brain stimulation may be an effective weapon against violence. iStock

What if it were possible to reduce someone's desire to commit a violent act? Could we harness such a technique to reduce crime? While this scenario may seem like the stuff of fantasy, it may not be too far from reality.

In a study published in the Journal of Neuroscience, an international team of researchers found that by electrically stimulating the prefrontal cortex—a region of the brain that controls complex ideas and behaviors—they were able to reduce a person's intention to commit a violent act by more than half.

The minimally invasive and safe technique, known as transcranial direct-current stimulation, achieved this result by increasing the perception that acts of physical and sexual assault were morally wrong—with the effect noticeable even after just one 20-minute session.

"The ability to manipulate such complex and fundamental aspects of cognition and behavior from outside the body has tremendous social, ethical, and possibly someday legal implications," Roy Hamilton, a neurology professor at the University of Pennsylvania's Perelman School of Medicine and senior author of the paper, said in a statement.

The researchers said that the new work approaches violent crime from a public health perspective—a viewpoint that has often been overlooked in favor of trying to understand its social causes.

For their research, the scientists randomly assigned 81 healthy adult participants to two groups.

The first group received the brain stimulation—which was administered via electrodes attached to the head—for 20 minutes. The second "placebo" group, meanwhile, received a low current for 30 seconds to mimic the stimulation and then nothing else.

It was directed specifically at an area of the prefrontal cortex, known as the dorsolateral prefrontal cortex. Previous research has shown that antisocial individuals often have deficits in this region.

However, it is not clear whether such brain deficits cause the antisocial behavior, or if the opposite is true: that the antisocial behavior is causing changes in the individual's brain via a process known as neuroplasticity—the ability of the brain to rewire itself in response to its environment. This is one of the main issues that the scientists wanted to address.

Once the participants in both groups had received either the stimulation or the placebo, the researchers presented them with two hypothetical scenarios—one about physical assault and the other about sexual assault.

On a scale of 1 to 10, both groups were asked to rate the likelihood that they would act as the protagonist in the scenarios and how morally wrong they felt the scenarios were.

The researchers found that the brain stimulation reduced the intent to committ physical and sexual assault by 47 and 70 percent respectively in the group that received it. The stimulation also increased the perception that the violent acts were morally wrong.

It is important to note that this is just a single study, so no firm conclusions can be drawn. Nevertheless, the results are tantalizing because they indicate that a relatively simple biological intervention could potentially be effective at reducing violent behavior.

"Much of the focus in understanding causes of crime has been on social causation," Adrian Raine, a Penn psychologist, said in a statement. "That's important, but research from brain imaging and genetics has also shown that half of the variance in violence can be chalked up to biological factors."

In future, the technique could be used on first-time offenders to reduce their likelihood of recommitting a violent act, or on adolescents who begin to show behavioral problems, the scientists said. But while the results are encouraging, much more research needs to be conducted before this type of technique can be used on high-risk individuals.

"We should, first emphasize that we need to replicate and extend these findings," Raine told Newseek. "Furthermore, we did not show that this reduced aggression as assessed by a laboratory measure, although it did reduce the intention to commit violence, which in itself is a prelude to violent behavior. But if future research supports and extends our findings, this could open the door to considering this as a new intervention in our fight against violence."

But would such interventions even be ethical?

"There is a history of misuse of biological research to prevent violence," he said. "Think of frontal lobectomies—disconnecting the prefrontal cortex with the rest of the brain. That was wrongful, but here we are doing the opposite—we are trying to enhance the functioning of the prefrontal cortex to reduce violence."

"Given that the procedure is safe and has minimal side-effects, then if it works, would it not be ethically wrongful to withhold it from those who give their free consent and who need it most to help them turn over a new leaf?"