Watching too much violence on television could make men more immature. A new study published by the Indiana University School Of Medicine says that young men who watched more violent programs on television had less mature brain development.

“We found that the more violent TV viewing a participant reported, the worse they performed on tasks of attention and cognitive control,” lead author of the study Dr. Tom Hummer said in a press release. “On the other hand, the overall amount of TV watched was not related to performance on any executive function tests.”

Hummer and other researchers used psychological testing and MRI scans on 65 healthy males, ages 18 to 29, with normal IQs. They measured their inhibitory control, attention, and memory. The researchers purposely chose an age group that they assumed didn’t frequently play video games, which themselves may pose risks toward violent tendencies.

For the study, the men reported the yearly amount of time they spent watching TV, and were told to keep a detailed diary of what they viewed for one week. The MRI scans were used to measure their brains' structures, and they were tested on executive function tasks, including making decisions, formulating plans, reasoning, problem solving, regulating attention, and inhibiting behavior in order to achieve goals. Hummer found that these executive functioning abilities were critical for controlling impulsive behaviors, including aggression. “The worry is that more impulsivity does not mix well with the behaviors modeled in violent programming,” Hummer said in the release.

When they compared the participants' TV habits to brain images, they found that violence had significant effects on the brain.“When we looked at the brain scans of young men with higher violent television exposure, there was less volume of white matter connecting the frontal and parietal lobes, which can be a sign of less maturity in brain development,” Hummer said. The tests also measured working memory, but this subtype of executive functioning was not proven to be a result of violent TV watching. 

White matter is the tissue in the brain that connects different brain regions. In a normally developing brain, the amount of white matter increases as the brain makes more connections, usually until about 30 years old. Despite their findings, the researchers were not able to determine a relationship between how the amount of violent television shows we watch and their impact on important aspects of brain functioning, like controlled attention and inhibition. “With this study we could not isolate whether people with poor executive function and slower white matter growth are more drawn to violent programming or if exposure to media violence modifies development of cognitive control,” Hummer said.

The researchers didn't make comments regarding whether or not we should stop watching violent TV. They couldn't determine why violent shows may stunt brain development, either. Nevertheless, there will probably be more answers to come soon. 

Source: Hummer T, Kronenberger W, Wang Y, Anderson C, Mathews V. Association of television violence exposure with executive functioning and white matter volume in young adult males. Brain and Cognition. 2014.