Taking another person's life is often seen as an impulsive act, but according to new research, the brain plays a larger role in processing this moral judgment.
Researchers at the Monash University in Australia studied brain activity in people during violent situations. They conducted an experiment aimed at identifying particular areas of the brain that may present factors in an individual's tendency to commit violence.
During the study, participants were asked to watch three videos portraying violent scenes. The first video showed a soldier killing an enemy soldier, while the second showed the soldier killing an innocent civilian. The last video, which was used by the researchers as a control, showed the soldier firing a weapon but hitting no one.
The first video was used to simulate justified violence and the second was for unjustified violence. Functional magnetic resonance imaging (fMRI) was used to observe the brain activity of the participants.
According to lead researcher Dr. Pascal Molenberghs, when the participants imagined themselves shooting civilians, their orbitofrontal cortex (OFC) showed greater activity than when they were shooting the enemy soldiers.
"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," Dr. Molenberghs said.
The temporoparietal junction (TPJ) was also affected during scenes that required moral judgment. This is where humans get their sense of agency, or the act of doing something deliberately and taking responsibility for it.
The results also demonstrated significant activity in the region of the brain known as the fusiform gyrus. This occurred when the participants imagined themselves killing civilians. The region is used when analyzing other people's faces, suggesting that the participants tried to humanize their imaginary victim by studying the expressions on their face.
"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," Dr. Molenberghs said.
Dr. Molenberghs and his team hope to continue their research regarding how individuals become desensitised to acts of violence. They will also look into how the personality and group membership of both the perpetrator and the victim affect the violence.
This study was published in the Social Cognitive and Affective Neuroscience journal.
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