"It appears that individuals who play violent video games habituate, or 'get used to,' all the violence and eventually become physiologically numb to it," write Nicholas Carnagey, M.S., and colleagues.
"The modern entertainment media landscape could accurately be described as an effective systematic violence-desensitization tool," they add.
Their article is in press for the Journal of Experimental Social Psychology. Carnagey is due to get a doctorate in psychology from Iowa State University this August.
Carnagey's team studied 257 college students, 124 men and 133 women.
First, the students noted their typical video game use. They also took aggression surveys and had their heart rate and galvanic skin response checked.
(Galvanic skin response measures the skin's electrical resistance. It's an indication of bodily [physiological] arousal.)
Next, the students played either a violent or nonviolent video game for 20 minutes.
The violent video games were Carmageddon, Duke Nukem, Mortal Kombat, and Future Cop. The nonviolent video games were Glider Pro, 3D Pinball, 3D Munch Man, and Tetra Madness.
When the game session ended, the students repeated the heart rate and galvanic skin response tests. Both groups showed similar results.
But the study wasn't over yet.
Watching Real-Life Violence
The students' last task: Watch a 10-minute videotape of real-life violence (shootings, prison fights, police confrontations, and courtroom outbursts).
During the screening, the researchers monitored the students' heart rate and galvanic skin responses.
Students who had played violent video games showed less physiological response to the real-life videos.
The study "demonstrates that violent video game exposure can cause desensitization to real-life violence," write Carnagey and colleagues.
"Children receive high doses of media violence," they note.
"It initially is packaged in ways that are not too threatening, with cute cartoon-like characters," the researchers continue. "Older children consume increasingly threatening and realistic violence, but the increases are gradual and always in a way that is fun."
Which medium is most desensitizing: TV, movies, or video games? And are some people more affected than others?
Those are good questions for future research, Carnagey's team notes.
SOURCES:: Carnagey, N. Journal of Experimental Social Psychology, July 17, 2006; online edition. News release, Iowa State University.
By Miranda Hitti
Reviewed by Louise Chang, M.D.
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