Why ‘Super Mario’ May Be Good for Your Brain, But ‘Call of Duty’ Isn’t

Brain scans show that first-person shooter games shrink the hippocampus in certain types of gamers.

Parents worried about the amount of time their kids spend playing video games have to sort through a lot of conflicting messages.

In recent years, there’s been mounting evidence that certain types of video games — particularly first-person shooters known as “action” video games — are actually good for the developing brain, boosting abilities in visual attention, short-term memory, and decision-making. But there’s a separate line of research showing that kids who play violent first-person shooters have an increased risk of aggressive behavior later in life.

So are video games bad or good for the brain? According to new research, the answer depends on the type of game and the type of brain.

A study published today in Molecular Psychiatry found that playing action video games like "Call of Duty" reduces the amount of grey matter in the hippocampus, a critical region of the brain largely responsible for storing long-term memories and processing emotional responses. In contrast, playing 3D “platform” games — named for gameplay that involves jumping around on floating platforms — like Super Mario appears to increase grey matter in the hippocampus. This is important because lower levels of grey matter in the hippocampus have been linked to higher risks of depression, Alzheimer’s, and PTSD.

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Greg West, an associate professor of psychology at the University of Montreal, was lead author of the study. He and his colleagues used computer analysis to study MRI brain scans of action video gamers and found a significant reduction in grey matter — related studies show a 2 percent shrinkage — in key regions of the hippocampus. And that was true both for people who had been gaming regularly for years and for people who trained on action video games for just 90 hours.

But why?

It turns out that there’s a turf war raging between two parts of your brain: the hippocampus on one side of the battle and something called the caudate nucleus on the other. The caudate nucleus is central to your brain’s “autopilot” functions and reward system, helping us know when to eat, drink, and procreate. The problem is that when our brains lean too heavily on the caudate nucleus, the hippocampus suffers.

“There’s evidence that stimulation of the caudate nucleus can directly inhibit the hippocampus, especially under stress,” said West, explaining that the caudate nucleus has evolved to work efficiently under pressure, even the self-inflicted stress of a video game. “But what we now understand is the overuse of that caudate nucleus system will result in inhibition of the hippocampal memory system, which will lead to underuse, and underuse will lead to cell death or atrophy.”

In a healthy adult brain, there should be an equal amount of grey matter in the hippocampus and the caudate nucleus. The new research shows that playing action video games can increase grey matter in the caudate at the cost of the hippocampus. Exactly why this happens isn’t fully understood, but it has something to do with learning styles.

Previous studies have shown that spatial learners — people who navigate mazes through landmarks and spatial clues — have more grey matter in their hippocampus than so-called response learners, who ignore landmarks and rely instead on memorizing a repetitive series of moves. Response learners, in turn, tend to have more grey matter in their caudate nucleus.

When West and his team ran a group of habitual action gamers through a virtual maze, 83 percent of them tested positive as response learners. That’s pretty high, West explained, given that only 50 percent of randomly selected healthy adults will solve the maze using a response learner approach.

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So why the high number? Was it because response learners are simply more likely to play action video games, or that the games themselves turn people into response learners and hurt the hippocampus in the process?

To figure that out, West’s team recruited 51 men and 46 women and randomly divided them into two groups: one that played action titles like "Call of Duty," "Kill Zone," and "Borderlands 2" and a second group that played 3D platform games from the "Super Mario" series. After playing the games for a total of 90 hours, the gamers who played the first-person shooters showed a strong bias toward response learning on the maze test. And that same subgroup that tested as response learners showed a distinct loss in hippocampal grey matter, similar to results from habitual action gamers.

Surprisingly, people who tested as spatial learners actually showed an increase in hippocampal grey matter after playing the very same first-person shooter games. And in the "Super Mario" group, both response learners and spatial learners responded positively to the 3D platform games, increasing their hippocampal grey matter.

So what’s the takeaway for parents?

Video games have a clear impact on the health of the hippocampus, which can increase or decrease the risk of emotional and cognitive disorders later in life. Playing action video games has the potential to inhibit activity in the hippocampus, but only in response learners. The trouble is that action video games also appear to stimulate the parts of the brain that cause people to become response learners.

So if you want to play it safe, it’s better to stick with "Super Mario."

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