Ethan Gibson loves playing Call of Duty.
"Basically shoot anybody who's not on your team," said Ethan, 16, of Charleston. "Shoot them dead."
Call of Duty simulates several war zones, and Ethan said the techniques he uses to play the game could improve anybody's marksmanship.
"It's all hand-eye coordination," said the junior at George Washington High School in Charleston. "It gets your heart pumping. 'Cause it's like, real. It's addicting. It's an adrenaline rush."
Ethan is 16 years old, and his brother, Jonah, is 14. They're not old enough to buy Call of Duty, which is rated "M" for mature. The rating requires a buyer be at least 17 years of age.
That's why the boys' mother, Grace Gibson, purchased the game for them.
"I still don't really like the violence," Gibson said. "But I don't see a violent streak in them. They don't hurt other people."
Ethan said he plays for fun and for no more than seven hours per week.
But he admitted he understands how a troubled person could get carried away by playing such a realistic game.
"I think this is just a boost for them. It just gives them a feeling of what it's like to take a life. And they take it way too far."
It's a theory that some who've committed mass shootings were also avid gamers.
"Violent video games deal with blood, gore, death, and destruction," said Michael Bayly, a psychology professor at University of Charleston. "A person who is desensitized is no longer bothered by it."
Bayly said a link exists between violent video games and negative behavior. He explained that violent video games can cause callousness, heightened physiological responses, and feelings of anger in the gamer--but these factors alone cannot independently cause a gunman to go on a shooting spree.
Bayly blames lackluster parenting.
"Saying it's the video game's fault is an excuse not to do your job. It's not the video game. It's the culture," Bayly said.
"It's a pastime," Ethan said. "And people take it way too seriously."
It's Ethan's other pastimes that convince Gibson to let her sons play on. Ethan said more than anything he loves playing the drums and has spiked a recent interest in basketball.
Gibson said they can kill zombies in the cyber world, just as long as they can make a distinction between fantasy and reality.
Half of the top twenty video games in the United States feature violence, according to data published on procon.org, a nonpartisan, nonprofit organization that compiles research on various topics.