Repeated viewing of violent scenes in films, television or video games could make teenagers behave more aggressively, US research suggests.The National Institutes of Health study of 22 boys aged 14 to 17 found that showing dozens of violent clips appeared to blunt brain responses.Dr Jordan Grafman said it might make aggression feel more “acceptable”.However, a UK expert said the reasons behind violence were too complex to be explained by laboratory research.
Call for child screen-time limit Games ‘don’t lead to violence’ The effect of violent imagery on young people has been debated from the early days of television, and, more recently, that debate has expanded to include video games.Various studies have suggested that exposure appears to have an effect on the way that the brain processes emotional responses, yet it is unclear whether this can have a direct impact on behaviour.
The US study, published in the journal Social Cognitive & Affective Neuroscience, involved 60 violent scenes from videos being collated, mostly involving street brawling and fist fights. The response of the boys as they watched the clips was measured in a number of ways.
They were asked to rate whether they thought each clip was more or less aggressive than the one which preceded it, and were brain scanned using functional magnetic resonance imaging, which shows in real time which areas of the brain are active.In addition, electrodes attached to the fingers detected increasing sweat – a sign of an emotional response.
The longer the boys watched videos, particularly the mild or moderate ones, the less they responded to the violence within them.In particular, an area of the brain known as the lateral orbitofrontal cortex, thought to be involved in emotional processing, showed less activity to each clip as time went on.