Viewing physical violence in the media can increase aggression in adults and children, previous research has shown.
Now, a new study has revealed that onscreen relational aggression - including social exclusion, gossip and emotional bullying - may lead to real aggression.
The study of 250 college women showed that mean screens may also activate the neural networks that guide behaviour.
"What this study shows is that relational aggression actually can cause a change in the way you think. And that matters because of course, how you think can change your behaviour," said Douglas Gentile, an associate professor of psychology at Iowa State University.
Gentile co-authored the study with Sarah Coyne and David Nelson, both researchers in Brigham Young University's School of Family Life; and Jennifer Ruh Linder, a professor of psychology at Linfield College (Ore.).
In the study, the researchers evaluated the cognitive patterns of the college women after they viewed one of three fictional video clips.
One clip depicted physical aggression, including a gun and knife fight that ended in murder. A second clip portrayed relational aggression, where girls steal boyfriends, spread malicious gossip and kick someone out of their social circle. The third clip was simply a scary scene, one that would raise the heartbeat.
Researchers assessed physiological arousal, finding that all three films produced similar levels of excitement. They then measured reaction times when aggressive or neutral words flashed on a screen. Participants who had watched either aggressive film clip ascribed more meaning to words connected with aggression.
"Past research has shown that viewing physical violence on TV activates aggressive scripts in the brain, but our findings suggest that watching both onscreen physical or relational aggression activates those cognitive scripts," Linder said.
"Viewers don't simply choose to imitate TV characters or make a conscious decision to engage in aggressive behaviour. Aggressive reactions are more automatic and less conscious than most people assume," she added.
Gentile sees the study having significance to today's societal norms.
"This matters because relational aggression tends to be considered more socially acceptable - it's often portrayed on television as funny and how friends treat each other. Yet, several studies are starting to show that relational aggression can cause long-term harm," he said.
And some of the most highly publicized effects have been a result of the rising incidence of cyberbullying, which Gentile says is a classic case of relational aggression.
"We're treating cyberbullying as if it's something totally different and totally new. It's actually relational aggression and it does all the things that relational aggression does," Gentile said.
"You can spread rumors, you can ignore people, I can unlike you on Facebook, I can tell your secrets, and I can lie and make up stuff. So this study relates to cyberbullying," he added.
The researchers say more research is needed to determine whether their results are gender-specific, and whether this script activation indeed changes behaviour.
The study was recently published by the journal Aggressive Behavior.