Researchers have shown the first experimental evidence that proves people who play violent games for three days continuously show more aggression.

Previous studies have shown that a single session of a violent game can have a short-term impact on aggression, but according to Brad Bushman, co-author of a new study and professor of communication and psychology at Ohio State University, long-term effects can be linked with violent video games, according to Science Daily.

"It's important to know the long-term causal effects of violent video games, because so many young people regularly play these games," Bushman said. "Playing video games could be compared to smoking cigarettes. A single cigarette won't cause lung cancer, but smoking over weeks or months or years greatly increases the risk. In the same way, repeated exposure to violent video games may have a cumulative effect on aggression."

A study was conducted on 70 French University students who were asked to participate in a three-day study and were allowed to play a violent and non-violent game for three consequent days, according to Science Daily report. After playing the game each day for about 20 minutes, the participants were asked to answer a questionnaire in response to a particular situation. The results of the study showed that students who played violent games had an increased aggression and hostile expectation and the ones who played non-violent games had no change in their hostile expectation or aggression.

"People who have a steady diet of playing these violent games may come to see the world as a hostile and violent place," Bushman said. "These results suggest there could be a cumulative effect.

"Hostile expectations are probably not the only reason that players of violent games are more aggressive, but our study suggests it is certainly one important factor. After playing a violent video game, we found that people expect others to behave aggressively. That expectation may make them more defensive and more likely to respond with aggression themselves, as we saw in this study and in other studies we have conducted," he said.

The study results are published online in the Journal of Experimental Social Psychology.