Updated Wednesday, February 6, 2013 at 08:35 PM
DAYTON, Ohio — A new Ohio State University study shows that playing violent video games can make people more aggressive over time, but the report’s co-author said it is impossible to link such games to violent criminal behavior like the recent Sandy Hook Elementary School shootings.
The new study provides the first experimental evidence that the negative effects of playing violent video games can accumulate over time, said Brad Bushman, an Ohio State professor of communication and psychology who researches factors that can influence aggressive behavior.
People who played a violent video game for three consecutive days showed increases in aggressive behavior and hostile expectations each day they played, he said.
Video-game publishers are facing growing pressure from Washington and advocacy groups concerned about possible links between violent games and tragedies like the mass shootings in Newtown, Conn., and Aurora, Colo.
President Obama last month called for the Centers for Disease Control and Prevention (CDC) to renew scientific research into the relationship between “video games, media images and violence.” He also urged Congress to support a bill that would grant the CDC $10 million to conduct this research.
The video-game industry adopted a voluntary rating system in 1994 that limits the sale and rental of games with violent or adult content to customers over ages 17 and 18, respectively. In June 2011, the U.S. Supreme Court ruled that a ban on the sale and rental of “violent” video games to minors is an unconstitutional infringement of speech rights.
The Ohio State study, conducted by Bushman with fellow researchers in France and Germany, involved 70 French university students who were told they would be participating in a three-day study of the effects of brightness of video games on visual perception.
The students then were randomly assigned to play a violent or nonviolent video game for 20 minutes on each of three consecutive days. After playing the game each day, participants took part in several exercises that measured their hostile expectations and aggression.
People who played the violent video games expected others to behave aggressively and were more likely to respond with aggression themselves, Bushman said.
Students who played the nonviolent games showed no changes in either their hostile expectations or their aggression.
“There is a difference on day one: Violent-video-game players are more aggressive,” Bushman said. “The difference is even bigger on day two, and on day three it is bigger still.”
Testing players for longer periods of time isn’t practical or ethical, he said.
Bushman’s research also showed that violent video games decrease pro-social behavior, such as helping or cooperating with others, and decrease feelings of empathy and compassion for others.
“It is impossible to know whether playing violent video games causes violent criminal behavior such as the Newtown shootings, because in our laboratory experiments we can’t give people guns to see if they shoot each other with them,” he said.
ARIANA CUBILLOS / AP
In this photo taken Sept. 2, 2009, a boy, using a toy weapon, plays a video game.
A bloody battle is seen in a frame made from Midway Games' Mortal Kombat: Deceptions.