Scene from Grand Theft Auto IV, card game

London - Playing a violent videogame for just an hour in three days is enough to increase aggressive behaviour, a study warns.

But scientists found that playing a non-violent videogame, such as a motor racing game, had no effect on aggression.

Research has already revealed that a single violent gaming session can increase short-term aggression, but this is the first to show longer-term effects.

Lead author Professor Brad Bushman, of Ohio State University in the US, said: “It’s important to know the long-term causal effects of violent videogames, because so many young people regularly play these games.

“Repeated exposure to violent videogames may have a cumulative effect on aggression.”

In the study of 70 French university students, some were given violent videogames, and others non-violent ones, and told to play them for 20 minutes a day for three days.

After each day, those who played the violent games increasingly expected others to behave aggressively towards them and behaved more aggressively themselves.

Professor Bushman said: “People who have a steady diet of these games may come to see the world as a hostile place. That may make them more defensive and more likely to respond with aggression themselves.”- Daily Mail