A new study of video games found that a player's perception of enemies as human, not alien, led the player to be more verbally aggressive afterward.

The study also found that men were more physically aggressive than women in behavioral tests taken after playing a first-person, shooter-type video game. And the more experience a person had playing violent games, the less that person perceived a shooter-type game to be violent.

"We found that if you just looked at who killed humans and who killed aliens, that didn't have any direct affect on aggressive outcomes," said Kirstie Farrar, associate professor in the University of Connecticut's Department of Communication. But a person's perception was different.

If a person perceived the enemy to be humanlike — regardless of the actual image on the screen — they were more likely to be "verbally and cognitively aggressive" than those who perceived enemies as less human.

The research was conducted by communication professors at UConn and Wake Forest University. They recruited 148 college students, with an average age of 19, to take part.

The participants played Quake 3 Revolution in a cubicle using a Sony PlayStation 2 on a 15-inch Panasonic television. The game pits the player as a first-person shooter in a "death match" against enemies. The goal is to shoot and kill each of five enemies.

Researchers split the participants into two groups: those who fought enemies that looked like aliens and those that looked like humans. The alien enemy had legs and arms, though it was a skeletal, red creature with angular fins jutting from its body. The human resembled a bald, obese member of a biker gang.

"One of the things that we thought was really interesting was that, as you perceived the character, or opponent, to be more human, you were more likely to generate more cognitive aggressive thoughts," said Rory McGloin, assistant professor in residence at UConn's Department of Communication.

People realize there are rules against acting violently, but it is more socially acceptable to think such thoughts, or verbalize them, McGloin said.

Instead of punching someone, however, video-game players who perceived their enemies to be more human were creating more "cognitively aggressive thoughts." The idea is that, if the player can't punch a person in the real world, he can still have aggressive thoughts toward that person, McGloin said.

The study measured cognitive aggression using a set of 50 incomplete words that the participant had to complete in two minutes. For example, "k-i" followed by two blank spaces could be "kiss, kick or kill." The resulting words were measured for aggressiveness.

Physical and verbal aggression was tested by asking the video-game players how they would respond to certain scenarios. For example, "imagine that you leave this building when you're done completing this survey. Someone bumps into you, spilling your drink and the contents of your backpack."

The topic of video games and violence resurfaced in Connecticut after law enforcement officials said the shooter in the Newtown massacre last December played many violent video games at home. Interest by policymakers in video-game research typically surges after a mass shooting, such as the 1999 killings at Columbine High School in Littleton, Colo., Farrar said.

"And then things die down, and that kind of goes away for a while, and then it happens again, unfortunately," Farrar said.

Farrar said video game violence is only one risk possible factor in aggressive behavior.

"It's one of many risk factors, but it is one that parents, for example, can exert some control over," she said. "So, I think parents need to be aware of what some of this research is suggesting when they make their decisions about [whether] they're going to let their kids play these games."