Jeremy Bailenson, author of " Experience on Demand: What Virtual Reality Is, How It Works, and What It Can Do ," is the founding director of Stanford's Virtual Human Interaction Lab and a professor in the Department of Communication. The views expressed in this commentary are his own.

(CNN) Last week, Dick's Sporting Goods banned the sale of assault-style rifles and Walmart raised the age of all gun buyers to 21. While our politicians debate next steps, these companies took swift action. Virtual reality hardware and software companies, which design top-selling video games, should follow suit.

Video games have one mandate: to be fun. But the companies that create and market them must also be socially and morally aware. They must consider the kinds of experiences they are developing, especially in first-person shooter games.

There is at least one documented case of a killer using a first-person shooter game to improve his combat skills. According to the Guardian, the Norwegian shooter Anders Breivik told the court in 2012 that he used "a holographic aiming device" in the game "Call of Duty" to develop his target acquisition abilities.

Breivik played a two-dimensional game, but virtual reality can take skill acquisition to a new level. Players can look all around the scene instead of just staring at a screen. Handheld devices vibrate to simulate touch. Most importantly, players use their arms and body to engage in actual combat moves, instead of just hitting buttons. As a result, the brain's motor system is engaged. Repeated movement while in virtual reality causes changes in brain structure , which in turn improves performance in the real world.

In other words, virtual reality is the ultimate training machine.

The military has been using virtual reality to train soldiers for decades. Today, everyone from NFL quarterbacks trying to improve their play, to retail employees trying to hone their customer service skills, are using virtual reality training to enable an infinite number of mental repetitions.

My argument here is not that virtual reality games are going to cause people to become violent, or that law enforcement or the military, for example, shouldn't have access to them. But if a possible mass-shooter wants to hone his craft, we shouldn't hand him an over-the-counter digital boot camp.

And there are steps we can take to strike a balance between fun and safety.

First, let's change the physics of bullets. Think about a Frisbee. In order to hit a target straight ahead, one needs to arc it to one side, to account for its return swing. If virtual reality bullets also traveled with a slight curve, then virtual shooters would always be pointing away from a target in order to eventually hit it. This learned side-aiming would likely carry over to the real world, and people would have trouble hitting a target straight ahead. A more subtle example can be seen in paintball, which has pellets that move slower than real bullets, and subsequently slightly change the way shooters aim the guns based on gravity, wind and other factors.

Second, guns in games shouldn't have the mechanics of real ones. You shouldn't hold a realistically weighted, gun-shaped object and pull a trigger in virtual reality. Instead, to operate a virtual gun, you should flick your wrist or bend your elbow. Before you discount this idea, think about the wildly entertaining types of weapons one typically sees in superhero movies -- guns that are far too big for normal people to carry, for example. This way, muscle memory for virtual guns will be abstract. A player can log hundreds of hours as a virtual shooter and be utterly perplexed when picking up an actual gun.

Another change that makes sense -- and I am happy that most, though not all, virtual reality games are adopting this strategy -- is to have the targets in games be nonhuman. For example, virtual shooters should aim at robots. Robots move and are shaped differently from humans. But designers can animate them to move much faster than humans, or to have skills that humans don't, like flying. Hence virtual reality would teach skills that would not work as well when aiming at people.

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In a perfect world, perhaps we wouldn't have virtual shooters at all. But for as long as we've had media, people have delighted in violent content. Some of my own favorite science fiction films and television series are gory and terrifying. The US Supreme Court has ruled that violent video games are a protected form of free speech , and for years the top selling video games have been first-person shooters.

Virtual reality is on the cusp of becoming a mainstream consumer product, and every year content becomes more and more realistic. Lucky for the designing companies, they have a little more time to think through some of the potential negative consequences of what they are creating.