When Jayne Gackenbach’s son took up Nintendo in the 1990s, she began to worry. As she watched him spend hours manipulating characters on the screen, she wondered if all that time in fictional worlds was messing with his head.

It’s a concern that any parent might have. But Gackenbach, a psychologist at MacEwan University, put the question to the test.

Put down your phone after an intense Pokémon Go session, and you might find yourself thinking about “catching” the dog across the street as if it were a character in the game. That momentary mix-up between the world on the screen and the physical reality of the street is called game transfer phenomenon, and it’s a common effect among gamers. As Gackenbach puts it: “Your brain’s kind of stupid, at least when it comes to reality.”

The effect isn’t confined to waking life. It also shows up in dreams, as well as during the blurry, hypnagogic period between sleep and waking. “Gamers have seen images from the game in front of their eyes, or felt involuntary movements as if their fingers were pushing the gamepad,” says Angelica B. Ortiz de Gortari, a postdoctoral fellow at the University of Liège who co-authored the first report on the phenomenon. Other researchers have documented similar effects in players of World of Warcraft and Tetris.

“When you alter people’s waking realities, their memory changes.”

Gackenbach’s research found that gamers report a greater sense of control in their dreams than non-gamers, as well as more awareness that they are dreaming—what researchers term “lucidity.” This suggested that spending time in a fictional, controllable world might teach gamers to view dream worlds through the same lens.

Her latest research extends the same questions to virtual reality, a technology that has a potentially wider reach than video games, with applications in areas from brain surgery to roller coasters. Manufacturers have leapt to fill the perceived demand, sparking bright-eyed proclamations that 2015—and then 2016—would be the year virtual reality goes mainstream. Following in the footsteps of Facebook’s Oculus Rift, HTC and Sony have also created their own immersive devices.

These gadgets are appealing because they’re temporary: Take off your headset, and you’re back in the real world. But Gackenbach suspects that as with video games, what is thought of as a momentary diversion is actually messing with people’s brains.

Because virtual-reality devices are more physically immersive than ordinary video games, Gackenbach hypothesized that the Oculus Rift would intensify the effect she’d observed. In a study she presented at a conference in June, participants played a 15-minute car-racing game on a computer, then described a dream from the previous night. Half the group donned the Rift to play the game; they remembered those dreams as higher in lucidity than the control group, which did not use the device. This difference disappeared when both groups reported on their dreams again the following week.

“All this points to one thing,” Gackenbach said. “When you alter people’s waking realities, their memory changes. The more you think you’re in one reality, it alters your memory of other realities.”

Could regular forays into virtual reality actually trigger lucid dreams, too? A survey Gackenbach conducted in conjunction with her study finds a correlation between heavy Rift usage and increased dream lucidity. Participants, including both Rift developers and gamers, described having increasingly lucid dreams as they spent more time immersed in virtual reality. “I seem more in control of my dreams now and am somewhat aware that it is a dream,” one technical writer reported.

“By using a virtual-reality device, you are putting yourself into a brain state that is remarkably like the REM brain state.”

Many virtual environments have a surreal quality, enabling users to experience activities—deep-sea diving, flying—would be unusual or even impossible in their real lives. Dreams operate in a similar way, leading some researchers to speculate that VR devices might train users to approach any “unreal” situation with heightened awareness. “One of the strategies to increase lucid dreaming frequency is to engage more in dream-related thinking,” says Martin Dresler, a psychologist at Radboud University, in the Netherlands. “So it’s indeed plausible that engagement in dream-like environments—like many virtual-reality programs are—increases lucid dreaming frequency.”

An increasing number of psychologists believe that the dreaming brain serves as a built-in virtual-reality generator, testing out various models of the world so that dreamers are better equipped to handle novel situations in waking life.

“A virtual-reality device is a simulation machine, just as the brain is,” says Patrick McNamara, a neuropsychologist at Boston University. “By using a virtual-reality device, you are putting yourself into a brain state that is remarkably like the REM brain state: a simulation without correction by external input. So it’s easy to recall similar brain states or simulations under those conditions.”

New technologies are almost always hyped as transformational. But Gackenbach's research provides some of the first evidence that virtual reality fundamentally alters the nature of consciousness. As far back as the 1990s, the art critic Jonathan Crary foresaw that the development of computer graphics would lead to the creation of visual spaces “radically different” from photography and film, where what people see no longer reflects the world that they can touch. In its transformative effect on human experience, virtual reality recalls the effect of engine technology, which with railroad and later airplane travel fundamentally altered how people understood space and time.

While virtual-reality devices might still be too cumbersome and expensive to be widely adopted, the recent Pokémon Go craze offers a glimpse at how this kind of technology might change society. Augmented-reality apps, where the virtual world overlays the real world rather than replacing it, might be less physically immersive than virtual reality—but they could be even more confusing for the brain. When bizarre things happen in an Oculus Rift game, they happen in a fictional world; when you play Pokémon Go, they’re happening right there on the street.

Gackenbach plans to look at augmented reality’s effects on consciousness with a new study on the popular video game. While she thinks augmented reality has a “huge future,” she also seems wary of what that might entail.

“We’re playing with people’s reality,” she says. “What’s that going to do?”