Washington: Young adult men who watch more violence on television show indications of less mature brain development and poorer executive functioning, according to a new study. Researchers from the Indiana University School of Medicine used psychological testing and MRI scans to measure mental abilities and volume of brain regions in 65 healthy males with normal IQ between the age of 18 and 29.
The men were specifically chosen because they were not frequent video game players. Lead author Tom A Hummer, assistant research professor in the IU Department of Psychiatry, said the young men provided estimates of their television viewing over the past year and then kept a detailed diary of their TV viewing for a week.
Participants also completed a series of psychological tests measuring inhibitory control, attention and memory. At the conclusion, MRI scans were used to measure brain structure. Executive function is the broad ability to formulate plans, make decisions, reason and problem-solve, regulate attention, and inhibit behaviour in order to achieve goals.
"We found that the more violent TV viewing a participant reported, the worse they performed on tasks of attention and cognitive control," Hummer said.
"On the other hand, the overall amount of TV watched was not related to performance on any executive function tests," Hummer added.
Hummer noted that these executive functioning abilities can be important for controlling impulsive behaviours, including aggression. Comparing TV habits to brain images also produced other results that Hummer and colleagues believe are significant.
"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," he said.
White matter is tissue in the brain that insulates nerve fibres connecting different brain regions, making functioning more efficient. In typical development, the amount or volume of white matter increases as the brain makes more connections until about age 30, improving communication between regions of the brain. Connections between the frontal and parietal lobes are thought to be especially important for executive functioning.
Hummer cautioned that more research is needed to better understand the study findings. "With this study we could not isolate whether people with poor executive function are drawn to programmes with more violence or if the content of the TV viewing is responsible for affecting the brain's development over a period of time," Hummer said.
The study was published in the journal Brain and Cognition.
