Researchers asked participants in a new study how likely they were to behave like protagonists in two hypothetical vignettes — hitting someone over the head with a beer bottle and raping an acquaintance.
Those who had received 20 minutes of painless, non-invasive brain stimulation one day earlier were, respectively, 47 percent and 70 percent less likely to say they would.
Thirty-one percent of the stimulation’s effect was attributed to participants’ perception that the hypothetical acts were morally wrong.
The new study is based on lead author Olivia Choy’s doctoral dissertation at the University of Pennsylvania. Choy is an assistant professor of psychology at Nanyang Technological University — and LifeZette spoke to her about the research.
“What’s new is the finding that ‘upregulating’ the prefrontal cortex can reduce the intent to commit violent acts. Moreover, we found that the reduction in aggressive intent was partly accounted for by improved judgments of how morally wrongful the aggressive acts were,” Choy said.
“This research may help to inform future approaches to reducing aggressive intent and behavior through a non-invasive, relatively benign intervention that targets a biological risk factor for crime.”
She noted that her research is still in the early phases — and that findings would “need to be replicated and extended before practical applications are considered.” However, the experimental design she employed sheds light on the causal role the prefrontal cortex plays in violence and aggression — a high bar the bulk of neuroimaging and neuropsychological studies in the past have largely failed to surmount.
Specifically, the researchers administered stimulation to the dorsolateral prefrontal cortex of 81 healthy adult volunteers who were recruited in Philadelphia between April 2015 and April 2016.
The next day, researchers measured those participants’ intent to commit physical and sexual violence via their responses to hypothetical vignettes depicting rape and physical assault. They also measured aggressive behavior through a task involving placing pins in a virtual doll meant to represent a friend.
The results of the study, “Stimulation of the Prefrontal Cortex Reduces Intentions to Commit Aggression: A Randomized, Double-Blind, Placebo-Controlled, Stratified, Parallel-Group Trial,” appeared in the Journal of Neuroscience earlier this week.
The study controlled for baseline levels of aggression and other factors that might have explained the effect. In addition, gender and ethnicity did not significantly impact the findings.
In her dissertation, Choy noted, “Understanding of the etiology of aggression and the development of new interventions are paramount to a public health approach to violence reduction.”
“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, in Penn Today. Hamilton is a neurologist at Penn’s Perelman School of Medicine and one of the authors of the Journal of Neuroscience write-up.
“Changes in behavior start with changing intent, and this is a first step.”
Johns Hopkins Psychiatry and Behavioral Sciences describes transcranial direct current stimulation (tDCS) as a “non-invasive, painless brain stimulation treatment that uses direct electrical currents to stimulate specific parts of the brain … It is cheap, non-invasive, painless and safe. It is also easy to administer and the equipment is easily portable. The most common side effect of tDCS is a slight itching or tingling on the scalp.”
Choy said she intends to continue her research into this exciting area of study.
“Reductions produced by tDCS were limited to aggressive intent, rather than aggressive behavior. It might be, however, that repeated sessions over a longer time period could produce changes in behavior. Nevertheless, changes in behavior start with changing intent, and this is a first step,” said Choy.
Michele Blood is a Flemington, New Jersey-based freelance writer and a regular contributor to LifeZette.