IMPACT OF VIOLENT MEDIA ON THE BRAIN : DEPENDS ON EACH INDIVIDUAL'S BRAIN CIRCUITRY
With the longstanding
debate over whether violent movies cause real world violence as a backstop, a
study published in PLOS One found that each person's reaction to violent
images depends on that individual's brain circuitry, and on how aggressive they
were to begin with.
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. The findings may have implications for
intervention programs that seek to reduce aggressive behavior starting in
childhood.
"Our aim was to
investigate what is going on in the brains of people when they watch violent
movies," said lead investigator Nelly Alia-Klein, PhD, Associate Professor
of Neuroscience and Psychiatry at the Friedman Brain Institute and Icahn School
of Medicine at Mount Sinai. "We hypothesized that if people have
aggressive traits to begin with, they will process violent media in a very
different way as compared to non-aggressive people, a theory supported by these
findings."
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 (shootings and street fights) on day one, emotional, but non-violent
scenes (people interacting during a natural disaster) on day two, and nothing
on day three.
The scans measured
the subjects' brain metabolic activity, a marker of brain function.
Participants also had their blood pressure taken every 5 minutes, and were
asked how they were feeling at 15 minute intervals.
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.
"How an
individual responds to their environment depends on the brain of the
beholder," said Dr. Alia-Klein. "Aggression is a trait that develops
together with the nervous system over time starting from childhood; patterns of
behavior become solidified and the nervous system prepares to continue the
behavior patterns into adulthood when they become increasingly coached in
personality. This could be at the root of the differences in people who are
aggressive and not aggressive, and how media motivates them to do certain
things. Hopefully these results will give educators an opportunity to identify
children with aggressive traits and teach them to be more aware of how
aggressive material activates them specifically."
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