How People Justify Killing Other People, According To Brain Scans


New brain research may offer some insight into a topic of great debate: how humans justify the use of deadly force in certain situations.

The study, published in the journal Social Cognitive and Affective Neuroscience, centered on a group of subjects who played video games in which they shot innocent civilians, a situation that may be considered “unjustified,” and enemy soldiers, a situation that’s considered more “justified.” During the activities, scientists measured participants’ brain activity via functional magnetic resonance imaging.

Researchers found that the neural systems that activate when one harms others show less vigor when that person believes the killing is justified. Dr. Pascal Molenberghs of Monash University in Melbourne said that these findings could pave the way for further study into how certain groups — including soldiers and police officers — become desensitized to violence, particularly when views about the victim and perpetrator are brought into question.

“When participants imagined themselves shooting civilians compared to soldiers, greater activation was found in the lateral orbitofrontal cortex (OFC), an important brain area involved in making moral decisions,” Molenberghs told EurekAlert.


“The more guilt participants felt about shooting civilians, the greater the response in the lateral OFC. When shooting enemy soldiers, no activation was seen in lateral OFC,” Molenberghs added. “The findings show that when a person is responsible for what they see as justified or unjustified violence, they will have different feelings of guilt associated with that — for the first time we can see how this guilt relates to specific brain activation.”

The recent study has the potential to add a scientific layer to the ongoing conversation about law enforcement’s relationship with men and women of color, and how those who bear the shield view their use of deadly force against victims in the context of their mission. In each situation that has recently made national headlines, officers gunned down and inflicted harm upon those who they considered to be resistant perpetrators. A recent incident in South Carolina involves an officer who shot a black man in the back eight times as the man ran away from him.

The high-profile case in Ferguson last year provides another potential example of how officers’ guilt — or the absence thereof — can factor into situations involving police and people of color. Days before a grand jury declined to levy charges against former Ferguson police officer Darren Wilson for the shooting death of black teenager Mike Brown, Wilson vehemently defended his decision, describing Brown as a “demon.”

Critics of the grand jury process said Wilson’s portrayal influenced the outcome of the case. “When I grabbed him the only way I can describe it is I felt like a 5-year-old holding onto Hulk Hogan… that’s how big he felt and how small I felt just from grasping his arm,” Wilson said during his testimony in November.

Outside of the law enforcement system, a similar debate about killers’ motives has unfolded in Boston, where a jury is deliberating how Dzhokhar Tsarnaev, the 21-year-old man who admitted to planting bombs at the Boston Marathon in 2013, will spend the rest of his life. Though it took them less than 12 hours to find Tsarnaev guilty on 30 counts, jurors still have to decide whether Tsarnaev will be executed.


Much of the legal arguments have centered on how Tsarnaev may have justified the act of terror and whether he felt any remorse about those acts. During the trial, a prosecutor described Tsarneav as a callous killer who orchestrated the act of terror — which killed three people and injured more than 260 others — as part of an effort to punish America and compel radical Islamists to rise up. Jurors also saw surveillance of Tsarnaev smiling as he walked through the aisles of a Whole Foods, purchased food and stopped by his college gym shortly before the bombing.

“The claim of course that he’s an Islamic radical and that this is almost an army-like attack on civilians,” CNN legal analyst Paul Callan recently said while assessing the battle ahead for Judy Clarke, Tsarnaev’s defense attorney. “It was so well planned and so callously planned so that civilians would die, so that children would be maimed.”

Research that uses video games to investigate bigger questions about people’s violent nature is quite controversial, especially when it attempts to examine a potential cause-and-effect relationship between gaming and violence. The new brain scan study comes on the heels of other research that dispelled notions that violent video games cause violent crime and “moral immaturity.” A study conducted at the University of Oxford examined the effects of various games and the length of time spent using video game consoles, and found that the time spent playing games had a greater impact than the type of games played.