Human trials of an electrical brain zapping device reveal that it can reduce people's intention to commit crimes. The device may also enhance moral judgment among people.

Transcranial Direct-Current Stimulation

The device, called the transcranial direct-current stimulation, zaps the prefrontal cortex portion of the brain, which experts believed, is responsible for controlling people's complex thoughts and behaviors.

In human trials, the device was found to slash a person's aggressive thoughts by almost 50 percent. The non-invasive tool was also found to improve a person's perception that physical and sexual assault were both morally wrong.

The results suggested that simple biological interventions, conducted alongside or separately from other psychological interventions, have the possibility to decrease violent behavior.

"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," said Roy Hamilton, a neurologist from the University of Pennsylvania and senior author of the study.

The findings were published in the Journal of Neuroscience on July 2.


Olivia Choy, the lead author of the study, explained that her team's research focused on stimulating the dorsolateral prefrontal cortex located on the top and front area of the brain. She said previous studies already found that people with antisocial tendencies have deficits in this region of the brain.

For the trial, the team recruited 81 healthy males and females aged 18 and above. The participants, who were also ethnically diverse, were initially given a series of questions that revealed their personalities, criminalities, and childhood social adversity.

The participants were then divided into two groups: the first received brain zaps for 20 minutes while the second one received low-current zaps for 30 seconds.

The researchers then asked the participants to rate two hypothetical scenarios involving physical and sexual assaults. They asked them to give a rating on a scale of 0 to 10, with 0 being no chance and 10 being 100 percent chance that they would commit the crimes in the presented scenarios. They also asked them to use the same scale and rate how morally wrong they felt about the situations.

The people who received the 20-minute brain stimulations showed a 47 percent less chance of committing physical assault and a 70 percent less chance of committing sexual assault. Overall, these participants also showed 54 percent less chance of exhibiting aggressive intentions and 31 percent increase in their moral judgment about acts of aggression.

Adrian Raine, a co-author of the study, said the trials can bring significant impact if stopping crime is viewed as a public health concern.

"We only did one 20-minute session, and we saw an effect. What if we had more sessions? What if we did it three times a week for a month?" Raine highlighted.

Future Applications

The researchers, however, clarified that the technique used for the trials is still at a very young developmental stage. This means that more studies are needed before the method can have practical applications.

For one, the study was aimed primarily at answering the question on whether the deficits in prefrontal cortex portion of the brain result to antisocial behavior or was it that committing crimes crippled the functioning of the prefrontal cortex.

Indeed, there was no significant difference in the level of aggressive tendencies when all the participants of the study were asked to "stab" a computer-generated image of a doll. For this test, the participants were told that they can relieve themselves of any negative feelings by inserting zero to 51 pins into the doll. The number of the pins they inserted represents the level of aggression they felt.

The next step for the researchers is to find out what happens when transcranial direct-current stimulation is administered over long periods and to find out what are the device's possible health risks.

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