Carey's 8-year-old son Tully plays the game "Skyrim" on their family computer. (Susan Hagner for WBUR)

"Oh, God, I'm going to die now," my 8-year-old son, Tully, laments. "Come on! How am I supposed to press Tab that fast?"

He's interrupted by a serene but authoritative female voice from the speakers. "You have five minutes left," it says. His computer time is almost up.

Tully started playing video games when he was still in preschool, first driving games because he was obsessed with cars, and then more elaborate games of exploration and battle.

His game-playing sparked the only major parenting conflict I've ever had with my husband, a software developer who’s worked on games and wanted to introduce Tully to their fun challenges. As a mother, I felt all my alarms going off: too much violence, too much screen time. At one point I even played the crack-cocaine card, as in: “You’re introducing our child to the media equivalent of crack cocaine!”

But then my attitude began to shift. Tully picked up reading early because he so wanted to decipher instructions on the screen. He started to spout historical facts. And he played one particular spelling game, "Bookworm Adventures," that was undeniably violent but also clearly educational — and I loved it. You got a grid of letters, and the longer a word you spelled, the harder you got to clobber a mythical enemy.

So I’ve ended up... confused. In over 30 years — a full human generation — computer games have evolved from primitive ping-pong to rich, immersive worlds, some with more content in them than "War and Peace." Many children now spend more time with games than with books or even TV. Critics warn that games may be addictive and lead to aggression. Supporters say that games may be the best educational tools ever. But what do we really know about their long-term effects?

I'm not the only one posing this question. Last week, President Obama asked Congress for $10 million to fund research into what causes gun violence, including possible links to violence in the media.

"Congress should fund research into the effects that violent video games have on young minds," he said. "We don’t benefit from ignorance. We don’t benefit from not knowing the science of this epidemic."

Surveys find that nearly all American children play some sort of digital games, whether it’s "Fruit Ninja" on a phone or "Halo 4" on an Xbox. They’re growing up at a time when games out-earn movies and television. "Clearly games are the 21st century’s most important form of media," says MIT professor Eric Klopfer. So what does it mean to grow up gaming?

Sharply Divided Research

Dr. Michael Rich, director of the Center on Media and Child Health at Boston Children’s Hospital, says it’s hard to get definitive about games when they’re evolving so quickly. They are, he says, "a rapidly moving, morphing and diversifying target. And second, the concerns people have are usually ones of long-term outcomes, so while the research can look at short-term outcomes, we need to have decades of time between when the 4-year-old plays the game and the 24-year-old is out in the world, to see if there are any long-term changes in brain development, in learning and in behavioral expectations."

At this point, the field of video game research is sharply divided between two opposing camps.

There’s a whole book that has alternating chapters with names like “Violent video games cause aggression” and “Violent video games do not cause aggression.” Or, “Video games help children learn” and then “Playing video games causes poor grades.” Or, “Video game addiction is a legitimate addiction” versus “Video game addiction is not a true addiction.”

On the one hand are findings that fuel parents’ concerns. Dr. Rich, who says he sees young patients every week for game addiction problems, lists a few: Violent games may increase some children’s fear and anxiety, desensitize them to violence, and, in some cases, may lead to aggression; some early research even implies that games may make kids worse at contemplative reflection. He says he hears from some teachers that they can identify which kids are the big video gamers.

“They’re not as socially comfortable interacting with real people, they don’t look you in the eye, they’re not able to read cues," Rich says. "They are not as able to take in information, synthesize it and bring it back. They’re more involved in reflexive responses to things — they are looking for the trigger."

Click to hear four video gamers weigh in on their playing and its effects.

On the other hand, some researchers point out that over the last generation, gaming has gone from fringe to almost universal and yet violent crime among youth has gone down.

"Often you think a kid is repeating some violent act over and over in the game and they’re learning to do bad things, they're trying, they're processing that into their brains," says Dr. Cheryl Olson, a public health researcher and co-author of the book “Grand Theft Childhood: The Surprising Truth About Violent Video Games.” "But really, when you think about what’s happening, they’re often learning how to solve problems. 'Hmmm, what happens if I open this chest here? What if I go into that room there?' "

She continues: "What are video games doing? If you have an age-appropriate game that's not too easy or too hard, a video game is teaching a child how to cope with failure, deal with frustration, delay gratification, and often doing it in a social context, where they’re learning to negotiate with their friends, working as a team, or 'OK, I beat you, you beat me, how do I handle all of these things?' "

That teaching can be so powerful, Olson says, that "One thing people are looking at now is, can schools use video game methods to teach better?"

The research by Olson's Harvard-based team, carried out under a $1.5 million grant from the federal Department of Justice, is the biggest study yet to directly address the question of whether video games cause violence.

Her work isn’t perfectly reassuring. It initially found a correlation between heavy playing of games rated "M for mature" and involvement in real-life fighting and bullying. But, she says, further analysis showed that aggressive personality traits and high stress levels in this subset of children accounted for the apparent link.

"You can say ‘Oh my gosh,’ but you have to unpack it further," she says. "That's why research doesn't lend itself well to soundbites."

Harvard psychiatry professor Eugene Beresin wrote last month about that research:

Is the tail wagging the dog, in other words? Are the children who are thought to wander towards aggression as a result of playing video games in fact attracted to video games because they are already prone to aggression in the first place? On the other hand, the researcher found that parent involvement and parent/peer support seemed to be protective of these negative behaviors. The study did in fact find that aggressive kids seem to be drawn to these games, and that these games might have affected them differently compared to the other kids who are not angry or aggressive. However, there seems to be a relationship between about 5-6% of kids who get into trouble, sometimes violent, and the amount of time playing violent games. It must be emphasized that there were no CAUSAL relationships found between violent games and violent behavior, just CORRELATIONS, and this could mean there are other things in life that may be involved.

My son Tully and his friends do act out computer game battles in real-life play sometimes, but it’s no more or less violent than when kids of my generation played cops and robbers, or acted out cowboy movies.

What I do see that’s different — and fascinating to me — is a style of play in which kids take on the role of the computer game itself, and offer each other choices and plot lines just as a game's creators do. In this imaginary game, which he calls "Mage," Tully’s giving me a mission from an alchemist:

Go to the money market and steal back my recipe, defeat the guards, and then I want you to sabotage the production field on the way out. Oh, by the way, this is a very advanced quest, so I wouldn’t do it until much later, or at least some later when you have better equipment and more life and stuff.

Gaming's Effects On 20-Somethings

How might all this translate into real life when Tully’s grown up, one of those “24-year-olds out in the world” that Rich mentioned? At Intrepid Labs — a co-working center for tech start-ups, particularly game companies, in Cambridge — 20-something gamers abound, including Alex Boerstler, the 25-year-old creative director of a company called Joust.

"Gaming has affected my life in a huge way," he says. The effects have been "overwhelmingly positive, though I will admit there are a lot of dark spots where gaming gets out of balance."

Boerstler says he spent a good five years of his youth playing "World of Warcraft" very heavily, and though he acknowledges that it got obsessive, he says it also brought him myriad benefits, including friendships that pointed him to art school and into Web design. And some of the skills honed by gaming have proven surprisingly relevant in the workplace.

For example, he once helped orchestrate 120 other "World of Warcraft" players in a mass attack on enemy cities.