No, you’re not just good at “Call of Duty” because you play it eight hours a… No, you’re not just good at “Call of Duty” because you play it eight hours a day.

It’s because you have a big brain, too, a recent research study says.

The study was conducted at the University of Illinois by a team of researchers, including Kirk Erickson, a psychology professor at Pitt and lead author of the study. Before coming to Pitt, Erickson worked at the University of Illinois as a graduate student and postdoctoral scholar.

Other members of the team include Ann Graybiel, a professor at the Massachusetts Institute of Technology and investigator for the McGovern Institute for Brain Research; Arthur Kramer, a psychology professor at the University of Illinois; and Walter Boot, a researcher from Florida State University.

The study, published Wednesday in the journal “Cerebral Cortex,” asserts that about a quarter of the variability of achievement seen in men and women who are trained on a new video game can be predicted — just by the size of three structures in their brains.

Research shows that expert gamers trump their novice counterparts in both attention and perception.

And other studies show that even with 20 hours of training, novices still show no signs of measurable cognitive development. These two findings suggest that existing individual differences in the brains of men and women could be a predictor of variability in learning rates, according to the research team.

The research branches into other areas of life too, Erickson said in an e-mail.

“This work could have enormous implications in other areas of life,” he said. “It reveals some interesting individual difference factors in learning that could be related to people with learning and memory deficits or degeneration of these structures.”

Graybiel and others have conducted animal studies that indicate the striatum, a collection of distinctive tissues tucked inside the cerebral cortex, is a sort of learning machine.

The team focused on three brain structures: the caudate nucleus and the putamen, both in the dorsal striatum, and the nucleus accumbens in the ventral striatum.

The caudate nucleus and the putamen are both involved in motor learning, and research shows that they help with the brain’s cognitive flexibility — that is, how quickly it is able to switch from task to task.

The nucleus accumbens, on the other hand, is associated with emotions related to reward and punishment.

In terms of video games, the researchers chose to focus on these three structures and question if their size is related to a person’s performance on a new video game.

Thirty-nine healthy adults, aged 18 to 28, were given MRI scans that analyzed these three regions of their brains. The researchers required that they all had not played video games for more than three hours a week for the past two years.

The team trained the participants on one of two versions of “Space Fortress,” a video game created in the ’80s at the University of Illinois as a tool for psychologists to study video game playing. The game, which features very low quality graphics, requires players to destroy a fortress without forsaking their own ships.

“We chose this particular game because it allowed us to have complete control over the different dimensions of the game — which is very important in science,” Erickson said. “This type of control allowed us to manipulate certain game parameters while keeping others constant.”

The question is, why not use real games on the market?

This degree of control is not available in off-the-shelf games, which would have created several problems in interpretation, he said.

Participants were split into two groups: one was told to focus on obtaining a high score while paying attention to different aspects of the game, and the other was told to employ variable-priority training, or to periodically shift their focus of training to different areas.

Research shows that variable-priority training encourages the same task in everyday life, often improving skill.

Simply put, the researchers found that bigger is indeed better — when it comes to the brain, that is.

Participants who had larger nucleus accumbens performed better in the early stages of training. The team suggested that this was because those players were more affected by achieving a certain goal — the nucleus accumbens is a part of the brain’s reward system, after all.

Additionally, those with a larger caudate nucleus and putamen performed better on the variable-priority training.

Even though Erickson and his team have hypothesized and theorized about these results, he said he still finds the way the research works a bit shocking.

“I think on some level all scientists are somewhat surprised that their research works the way it does,” he said.

“The brain remains a mystery on many levels,” he said, so there is still more to learn.

Be it destroying a fortress or going for that 10-kill streak, bigger is better — regarding your brain structure, of course.