Aggressive people's brains react lesser to violent media

A new research has found that people with aggressive traits react differently to exposure to violence.

The study, which was led by researchers at the Icahn School of Medicine at Mount Sinai and the NIH Intramural Program, featured brain scans which revealed that both watching and not watching violent images caused different brain activity in people with different aggression levels.

Lead investigator Nelly Alia-Klein said that they had hypothesized if people had aggressive traits to begin with, they would process violent media in a very different way as compared to non-aggressive people.

After answering a questionnaire, a group of 54 men were split by the research team into two groups, one with individuals possessing aggressive traits, including a history of physical assault, and a second group without these tendencies. The participants' brains were then scanned as they watched a succession of violent scenes on day one, emotional, but non-violent scenes on day two, and nothing on day three.

Investigators discovered that during mind wandering, when no movies were presented, the participants with aggressive traits had unusually high brain activity in a network of regions that are known to be active when not doing anything in particular. This suggests that participants with aggressive traits have a different brain function map than non-aggressive participants, researchers said.

Interestingly, while watching scenes from violent movies, the aggressive group had less brain activity than the non-aggressive group in the orbitofrontal cortex, a brain region associated by past studies with emotion-related decision making and self-control. The aggressive subjects described feeling more inspired and determined and less upset or nervous than non-aggressive participants when watching violent (day 1) versus just emotional (day 2) media. In line with these responses, while watching the violent media, aggressive participants' blood pressure went down progressively with time while the non-aggressive participants experienced a rise in blood pressure.

Dr. Alia-Klein said that the results would give educators an opportunity to identify children with aggressive traits and teach them to be more aware of how aggressive material activated them specifically.

The study is published today in PLOS One.