We tend assume that if you spend hours and hours shooting up people in a video game like Halo, all the violence can leave you angry.
But it's not the violence. "Across our studies we look at both violent and non-violent games. What we found is it's not the content that drove post-game aggression, it was more whether you're frustrated in the game itself by a failure at mastery," explains the University of Rochester's Professor Richard Ryan.
Ryan had his test subjects play violent and non-violent games, and then he played tricks on them, like sabotaging the controls to slow down the response time. He found that post-game rage was linked not to what game you played but to how well, or badly, you played it.
What created rage was not shooting, it was losing.
And it doesn't even have to be a violent game! You could be playing Candy Crush.
"Any game where you feel like you can't control it."
And it doesn't even have to be games, you could become enraged when your word processor computer is just running slow or losing data.
"Our theory says that too leads to aggression," said Ryan. "Very similarly too, you see a lot of aggression after sports - if you feel like you've a had a bad call from the ref - it feels like it takes the game out of your control."
We all know how that feels. So what does this research say for parents who are worried about the effects of video games on their kids? Well, seems to me, instead of worrying about the violence, you may just need to upgrade your Internet speed. Or buy your kid a faster computer.