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Men have more activity in their mesocorticolimbic centre, the region of the brain researchers say is associated with reward and addiction, than women. ((Associated Press/Jim Mone))

Men are more rewarded by video games than women on a neural level, which explains why they're more likely to become addicted to them, researchers at Stanford University claim.

In a brain-imaging study by Stanford's school of medicine, researchers discovered that, when playing video games, the part of the brain that generates feelings of reward is more stimulated in men than in women. That helps explain why they're more likely to get hooked, the study's authors say.

The researchers, whose work was recently published online in the Journal of Psychiatric Research, created a video game where a vertical line, or a "wall," divided the middle of the screen. Ten balls would appear at the right of the screen and move toward the wall, and test participants would have to click on them before they hit. If the balls were clicked on before they hit the wall, the player would gain territory; if the player missed, space would be lost.

The test subjects — 11 men and 11 women — were told to click on as many balls as possible but were not told that they would win or lose territory.

All participants quickly figured out the point of the game, but the men wound up gaining significantly more territory than the women because they identified which balls — the ones closest to the wall — would get them the most space.

Males more motivated to win

"The females 'got,' the game, and they moved the wall in the direction you would expect," said Allan Reiss, who headed up the study, in a statement. "They appeared motivated to succeed at the game. The males were just a lot more motivated to succeed."

Participants were hooked up to a functional magnetic resonance imaging machine, which produces an image that shows which parts of the brain are working during a given activity. Researchers saw activity in the brain's mesocorticolimbic centre, the region they said is typically associated with reward and addiction.

Male brains showed much greater activity, and the amount was proportionate with how much territory they gained, which wasn't the case with women.

The scientists also found that three brain structures — the nucleus accumbens, amygdala and orbitofrontal cortex —influenced each other more in men than in women, and the better that circuit was connected, the better the males did in the game.

"I think it's fair to say that males tend to be more intrinsically territorial," he said. "It doesn't take a genius to figure out who historically are the conquerors and tyrants of our species — they're the males."