People who played action video games that involve first-person shooters, such as Call of Duty and Medal of Honor, experienced shrinkage in a brain region called the hippocampus, according to a study published Tuesday in Molecular Psychiatry. That part of the brain is associated with spatial navigation, stress regulation and memory. Playing Super Mario games, in which the noble plumber strives to rescue a princess, had the opposite effect on the hippocampus, causing growth in it.
Scientists have done dozens of studies looking to see if playing video games affects people’s health and behavior. There’s some evidence they may improve people’s visual short-term memory and eye-hand coordination. But researchers keep looking for negative consequences, too.
These researchers first asked 33 participants how often they had played video games in the past year. They scanned people’s brains using MRIs, and found that the action video game players, who reported spending an average of 19 hours playing action video games each week, had less gray matter in the hippocampus than non-video game players. The difference was statistically significant.
Then the researchers asked 43 other people who don’t usually play video games to spend 90 hours over about 10 weeks playing either action video games or Super Mario games in a controlled setting.
People in the group that played action video games lost gray matter in the hippocampus, according to Gregory West, the study‘s lead author and an associate professor of psychology at the University of Montreal. And people who played Super Mario games gained gray matter in the hippocampus.
“While we train up this one system, this other system is potentially being neglected and potentially showing signs of atrophy,” West says.
Simone Kuhn, a professor of neural plasticity at the University Clinic Hamburg-Eppendorf in Germany, says people who play action video games shouldn’t be too concerned.
“I would never interpret this finding as a big warning against action video games,” she says. Why did action video games seem to shrink the hippocampus, while a different type of game seem to have caused it to grow? West and his colleagues have some ideas.