Still convinced that violent video games are harmless fun? You might want to put down that console and consider the findings of two new research papers.

The first, a meta-analysis of 98 studies with nearly 37,000 participants, concludes without equivocation that “violent video games increase aggression.”

The second, which describes new research from Italy, provides further evidence of that troubling dynamic, and indicates they also lead to “decreased self-control and increased cheating.”

“Many real-world decisions require self-regulation of moral behavior,” writes a research team led by psychologist Alessandro Gabbiadini. “Our study indicates that playing violent video games can interfere with this ability.”

"Participants who played a violent video game for only 35 minutes exhibited less self-control, cheated more, and behaved more aggressively than did participants who played a nonviolent video game."

The Italian study, published in the journal Social Psychological and Personality Science, featured 172 high school students. After 10 minutes of practice, each played a violent video game (Grand Theft Auto III or Grand Theft Auto San Andreas) or a non-violent one (Pinball 3D or Mini Golf 3D) for 35 minutes.

Participants were told they could snack from a bowl of M&Ms placed next to the computer as they played. However, they were also warned that eating too much candy too quickly was unhealthy. Their level of self-control was measured by noting how much of the chocolate they consumed.

After finishing play, they completed a survey designed to measure their level of moral disengagement. On a one-to-seven scale (“completely agree” to “completely disagree”), participants responded to a series of statements indicating a tendency to think of moral behavior in relative terms.

Examples include “Compared to the illegal things people do, taking some things from a store without paying for them is not very serious” and “It is OK to insult a classmate, because beating him/her is worse.”

The experiment concluded with two tests designed to measure aggression and the tendency to cheat.

Participants were told they could earn one raffle ticket for each problem they solved on a 10-item logic test. They scored their own responses and took a lottery ticket from an envelope for each correct answer. Researchers measured cheating by comparing the number of tickets taken with the actual number of correct answers.

In addition, participants took part in a “competitive reaction time task” in which the winner of each round “could blast the loser with loud noise through headphones.” Researchers measured aggression by how loud and long participants blasted the unpleasant sound.