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?”