(CNN) -- A researcher in Wisconsin says he figured out how you can improve your brain power and his advice is "just go play video games."
That includes the sometimes controversial "first-person shooters" like "Call of Duty" -- known for their often graphic violence.
Psychology professor Shawn Green isn't just playing games.
"These games will trigger the fight or flight response," said Green.
Brain scans show he's improving his perception -- cognition and critical thinking.
"You have to identify targets among clutter, you have to make very quick decisions, but they have to be accurate," he said.
Professor Green says its not just first person shooter games, it's also first person driving ones that can benefit brain cognition.
Even after the game is over, Professor Green says the benefits continue.
"We've seen that they've lasted anywhere from six months to two years when we tested," he said.
But do these games increase aggression?
"There is realistically no strong link between playing these types of games and any kind of real criminal violent behavior," Green said.
He does say video game violence could possibly make children more angry.
"Not gonna turn a kid into an ultra-violent individual. On the other hand, you don't want to diminish the fact that it could lead to those minor changes in aggression."
Professor Green says there are new non-violent first-person kid action games:
"In this case you don't shoot bullets or lasers, you shoot plungers at rabbits, so it has very similar dynamics, mechanics and it turns out it has very similar effects on visual attention. But wouldn't be considered a violent game. There is kind of host of games that are coming up in that sphere," he said.
He also says new research shows other gaming forms can do the trick
"Real-time strategy games often aren't as violent. There's some new research suggesting that these have some of the same effect as action games have."
Down the line, Professor Green plans to use MRIs, to see if people's cognition improves when they play those video games.