Do video games make children aggressive? What about cognition? These are not simple yes or no questions as a recent study performed by researchers at the University of Montreal and McGill University in Canada found out.

Their work suggests first-person shooters can reduce gray matter, particularly in the hippocampus — a critical brain region involved in memory, navigation, and spatial learning. The findings don’t apply to all kinds of action video games, though. Rather, the scientists learned that those video games where no spatial memory strategy is required are responsible for the effect. Those video games that emphasized spatial memory strategies were actually associated with an increase in gray matter in the hippocampus.

In-game overlaid map from Call of Duty. A new study found such approaches are turning gamers into responsive spatial learners. This is associated with less gray matter in the hippocampus. Credit: Wikia.

Gray matter bread crumbs

For the first part of the study, the researchers recruited 33 volunteers who either habitually played video games or never did so. Before the experiment, each participant was interviewed about the strategies they use to navigate in order to learn whether or not they were spatial learners or response learners. A spatial learn navigates an environment such as a maze by learning about the relationship between specific landmarks and target objects such as the middle of the maze. Contrary, a response learner uses counting, patterning, and memorizing a series of steps to find their target along the way.

After the participants had their brains scanned, the team found that habitual action video gamers had significantly less gray matter in their hippocampus and used response strategies more.

In the second and third part of the study, 42 and 21 participants, respectively, had to play 90 hours of either an action video game (Call of Duty or Battlefield), a video game platform (Super Mario 64), or an action-role playing game (Dead Island). After the training round, the participants underwent magnetic resonance imaging (MRI) brain scans and had their brain tissue density measured.

Gamers who used non-spatial response strategies had significantly less gray matter in the hippocampus. Those who used hippocampus-dependent spatial strategies, however, saw a marked increase in gray matter.

“These results show that video games can be beneficial or detrimental to the hippocampal system depending on the navigation strategy that a person employs and the genre of the game,” says Greg West, associate professor at the University of Montreal, who led the research.

West and colleagues think that in-game GPS or maps overlayed on the display of most action games are making gamers too spatially responsive. Action games that don’t have overlaid maps prod players to remember relationships between landmarks and thus encourage spatial learning.

“These results show that video games can be beneficial or detrimental to the hippocampal system depending on the navigation strategy that a person employs and the genre of the game,” the authors reported.

Findings appeared in the journal Molecular Psychiatry.