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An avid teenage gamer. A seasoned U.S. Marine. Each has achieved a level of reflexive conditioning that makes him deadly with a weapon, and each has been desensitized to the act of pointing his weapon at another human being and pulling the trigger. There's a crucial difference, however. The Marine is part of an organization that instills discipline in the use of violence. He operates under strict rules of engagement. The teen doesn't.

A Study of Killing
How did we get to such a state of affairs? David Grossman, a retired Army psychologist, has written extensively about the process that takes immature, untrained teens and turns them into killers. His research, called "killology," is documented in his Pulitzer Prize-nominated book, On Killing, which tells how the military confronted a unique problem: Not enough of its soldiers were actually shooting their weapons in battle. Studies after the Civil War and World Wars I and II found that a relatively small number of soldiers—as few as 15 percent—actually fired at the enemy. "Obviously, you can't have that situation in war," he says.

The military realized that simply learning to shoot at a round bull's-eye did not condition soldiers to the battlefield reality of sighting on another human being and taking a life. There was a psychological barrier that had to be overcome. "Hardwired into the brains of most healthy members of most species is a response against killing their own kind," Grossman explains. By using human-shaped pop-up targets and other means, the military was able to desensitize soldiers to the act of aiming at a human shape, which increased the firing rate to as high as 90 percent by the Vietnam War.

With the invention of video game technology, the military began to use this equipment to further train its soldiers. The Marine Corps, for example, adapted a version of the popular game Doom to hone Marines' reactions in a combat environment. In many ways, video games, particularly first-person shooters, exactly mimic the process used by the military. Teens (including the gunmen at Columbine High School) log countless hours with these same games—but without the discipline that comes from military training and, obviously, without any need to develop these skills in the first place.

The psychological process involved in this type of training is called "operant conditioning." Not only is the mind desensitized to a certain level of violence and to the process of sighting on an enemy, but the shooter also develops the muscle memory necessary to become an expert marksman. Grossman cites the example of one school shooter, Michael Carneal, who fired into a group of students at a high school in Paducah, Ky., in 1997. "The kid had never fired an actual pistol in his life," says Grossman, who was an expert witness at Carneal's trial. The teen stole a .22-caliber pistol from a neighbor's house and practiced with two clips of ammo the previous night. That was the sole extent of his marksmanship training—at least with live ammo. "But he'd been on the simulator for nearly a lifetime," Grossman says. The boy's family had converted their two-car garage into a playroom lined with point-and-shoot arcade games, a genre Grossman calls "murder simulators."

Carneal took the stolen gun to school and opened fire on a group of students with an astounding degree of accuracy. "You have kneeling, scrambling, screaming targets," Grossman explains. "Carneal fires eight shots at eight different targets. Five of them are head shots, the other three upper torso. Now, I have trained the FBI. I have trained Navy SEALs, Green Berets and Texas Rangers, and when I tell them about this case, they're simply stumped. Nowhere in the annals of law enforcement, military or criminal history can we find equivalent achievement."

It was, Grossman says, a classic case of operant conditioning.

Feeding the Dog Brain
Until recently, manufacturers of hostile video games and other violent media have dismissed the connection between their products and teen violence, claiming that any correlation has been, at best, anecdotal. But science is now proving the connection.

The Indiana University School of Medicine has conducted a series of tests using functional Magnetic Resonance Imaging (fMRI). This allows researchers to compare the brain activity of teens consuming a heavy diet of violent media to those not as heavily exposed. The scans show decreased brain functioning in the prefrontal cortex, the part of the organ that regulates emotions, impulsivity and conscience.

Grossman explains it this way: "Our frontal lobes are what make us human. This is where the written word and the spoken word are processed and where, incidentally, abstract concepts like God and spirituality exist. Lying underneath the forebrain is the midbrain, the mammalian brain, the part of your brain which is identical to your dog's brain. Images, particularly violent images, bypass the forebrain and go straight to the dog brain."

The differences are also apparent between left and right brain, he adds. "The right brain is your artistic, creative, innovative brain. The left brain is your logical, rational, predictive brain. Your right brain really is kind of like the little devil who sits on one shoulder and thinks foolish things. The left brain is sort of like the little angel who sits on the other shoulder and says, 'Oh, that will get us in trouble; we can't do that.' The left brain really does have veto power."

According to an Indiana University study of brain scans, teens exposed to a heavy media diet, particularly violent media, show almost no activity in the left brain or in the frontal lobes. And just as muscles atrophy when they're not used, the frontal lobes and rational portion of the brain also atrophy when not exercised. Grossman makes it clear that teenagers in this condition aren't necessarily going to become violent criminals, saying, "Not every teen who plays violent video games is going to become a school shooter." He's quick to add, however, "But every school shooter was a consumer of violent video games."

While young people who suppress left-brain activity by feasting on violent media may not open fire in the school cafeteria, there are still consequences. "This kid just won't do his homework, because the ability to understand the logical ramification of not having his homework done tomorrow morning doesn't click," Grossman says. "Who knows what he'll do behind the wheel of a vehicle. This kid is cocked and primed to do drugs. He does not understand, because the left brain is catastrophically shut down."

The good news is that this change in brain functioning does not appear to be permanent. Studies have shown that children weaned from a heavy media diet do better on school aptitude tests, and school administrators report fewer incidents of playground violence and bullying.

A Cultural Problem Needs a Cultural Response
The American Medical Association, American Psychological Association, American Academy of Pediatrics, and American Academy of Child and Adolescent Psychiatry made a joint statement to Congress in 2000 regarding the link between media and societal violence. "They said that 30 years of research and a host of sound, scholarly studies have proven that media violence causes violence in our society," Grossman says.

The solution, it would appear, is obvious. But as much as parents may wish to ban violent media, it's not going to happen. We can, however, prevent impressionable children from consuming it. "There's a social cost to several things that we allow for adults but not kids," Grossman states. "Driving. Alcohol. Tobacco. … We can say there are some things adults can have that kids can't."

Of course, we've all heard the entertainment industry argue, "If you don't like the violence, just turn it off." Grossman's rebuttal is simple. He shares a personal story from one of the first school shootings, which happened to take place in his hometown of Jonesboro, Ark. He stood helplessly, watching a forlorn, single mother as she waited for the final identification of her daughter's body at the morgue. "This mom had lost everything she had in the world because of two kids who decided to act out a violent video game," Grossman recalls. "You tell that single mom who lost her daughter to just hit the 'off' switch."

Published July 2006


Plugged In Plus
"After the first ambush we were in, Lt. Fick and I were discussing [Grossman's book On Killing] and how today's guys have no problem firing their weapons. For instance, Fick remarked after a firefight, 'Did you see what they did to that town? They [expletive] destroyed it.' Cpl. Trombley, the machine-gunner who was next to me in that ambush, he'd even been sort of ecstatic, comparing it to Grand Theft Auto, the video game." —Evan Wright, author of Generation Kill, about his experience of being embedded with a U.S. Marine reconnaissance unit in Iraq