ROBERT SIEGEL, HOST:
Violent video games have been one focus of the recent national conversation on gun violence. The big question is: Do they make people more violent in the real world? And while the answer to that question is unclear, one thing is indisputable: Violence sells. The most popular video game franchise is Call of Duty, where killing is the goal.
NPR's Sami Yenigun looks into why violent games appeal so much to so many.
SAMI YENIGUN, BYLINE: There are over 40 million copies of Call of Duty in the U.S. One of them is at iStrategyLabs in Washington, D.C. It's a digital marketing agency, and in the center of the office is an 80-inch television, where employees sometimes take breaks and shoot at each other.
MEGAN ZLOCK: Yeah, it's a military game where basically you have an objective on each level, and you need to, like, pass the objective whether that's getting past...
SARAH SUGARMAN: Checkpoints.
ZLOCK: ...like super soldiers.
YENIGUN: Megan Zlock and Sarah Sugarman are gamers. Sugarman likes playing RPGs or role-playing games. She says, for the most part, they're less violent than first-person shooters like "Call of Duty." Zlock, on the other hand, likes her games bloody, especially "Mortal Kombat" and "Diablo."
ZLOCK: You're really just plowing through and killing, like, millions of demons throughout the progress of the story.
YENIGUN: A story which, she says, is better with violence.
ZLOCK: If you want to create a good narrative, you need to create conflict, and, like, violence is a really easy way to create conflict.
YENIGUN: Both Zlock and Sugarman, along with the dozen or so people around the TV, say that violence doesn't have to be part of a good game, but sometimes, it makes the game better. Dr. Douglas Gentile, who studies the effect of violent video games on children, says violent games tap into a primal instinct.
DR. DOUGLAS GENTILE: There are two things that, you know, force us to pay attention. One is violence, and the other is sex. Whenever either of those are present in our environment, they have survival value for us.
YENIGUN: Gentile explains there's a very basic reason that a lot of people think violent games are more exciting than, say, "Tetris."
GENTILE: These gamers do have an adrenaline rush, and it's noradrenaline, and it's testosterone, and it's cortisol. These are the so-called stress hormones. That's exactly the same cocktail of hormones you drop into your bloodstream if I punched you.
YENIGUN: Getting punched in real life, not fun.
GENTILE: But when you know you're safe, having that really heightened sense of stress can be fun.
YENIGUN: Or as Zach Solly of iStrategyLabs puts it...
ZACH SOLLY: It just feels, like, awesome.
YENIGUN: The palpable, frenetic energy that fills this room suggests that Zack Solly's opponents are feeling pretty awesome too.
SOLLY: When I play this, like, since it is more realistic, like it is easier to, like, lose yourself in the game while you're playing it.
YENIGUN: So violence provides thrills that we're hardwired to enjoy, and video games offer an immersive experience that were hardwired to crave, according to Gentile. He says there's an A, B and C of human motivation, and that video games hit all three. A is for autonomy.
GENTILE: You're holding a controller so you are in control.
YENIGUN: B is for belonging.
GENTILE: If you play with other people or you have friends who play the same game or you play online, you also are meeting your belonging need.
YENIGUN: C is for competence.
GENTILE: They often train you how to play as you're playing, and so you start feeling competent.
YENIGUN: Which brings us to a decades-old question: Do violent video games make people more violent? Gentile says his research shows that children who play more violent games by and large behave more aggressively. But he adds...
GENTILE: That does not mean school shootings.
YENIGUN: Gentile says we don't know if games turn people into murderers because the sample size is just too small. And that exposure to violent games is likely just one part of a bigger picture.
GENTILE: Take the killers at Columbine High School. They had been bullied. They had psychiatric illnesses. And, yes, they also consumed a lot of media violence. No one of those things was the cause.
YENIGUN: The people at iStrategyLabs playing "Call of Duty" aren't scientists, but they say something similar. Again, Zack Solly.
SOLLY: I think that people who are going to be prone to violence might be affected by video games, but I think someone who is of, like, sound mind is not going to be affected by a violent movie or a violent video game.
YENIGUN: There is one thing that's for certain: Violence sells. In half of the top 10 selling games of 2012, the main objective is taking lives.
Sami Yenigun, NPR News.