Back in the early 1990s, virtual reality was poised to revolutionise gaming. Games giant Sega, makers of the hugely popular Genesis console, had just unveiled the Sega VR project. At the project’s core lay a headset that coupled state-of-the-art graphics with movement tracking software to immerse gamers in a rich and vibrant virtual world. At least, that was the plan.

The reality of Sega’s virtual reality fell some way short. The biggest problem was that the onscreen graphics didn’t keep pace with the gamer’s head movements, triggering a form of motion sickness. Thomas Piantanida, then principal scientist of SRI International's Virtual Perception Program, test drove a prototype in 1993 and came up with a name for the vomit-inducing phenomenon. The headset’s graphical output, he said, lay in the “barfogenic zone”. By 1994, Sega had quietly shelved the project.

Virtual reality is back in the news this week, as Facebook has just forked out $2 billion for Oculus VR. The social media giant is betting that immersive virtual and augmented reality will become a part of people’s everyday life, which raises the question of whether the technology has managed to escape the barfogenic zone during the last 20 years.

Last year, people’s first descriptions of using the early developer versions of the Oculus Rift device didn’t augur well.

“BOOAGHHOODD THE MOTION SICKNESS,” said one Reddit user. “I couldn’t last long, I had to close my eyes a bit and take it off relatively early.”

Other Reddit users reported similar experiences. “I felt quite v-sick my first day of using it but seem to have my v-legs now.”

That was 10 months ago. In the intervening time, Oculus has made great strides in reducing – perhaps even eliminating – the motion-sickness problem.

The kind of head tracking technology the company uses can normally help refresh on-screen images about 125 times per second – from the beginning the Oculus’ creators insisted on a faster refresh rate of 250 times per second to reduce movement lag. The latest version of the headset refreshes on-screen images four times faster still, reducing the lag between head movement and the headset response to just 2 milliseconds. Reportedly, users can tell the difference. Virtual reality has finally left the barfogenic zone.

Some researchers, however, argue that an entirely different problem may lie ahead for the virtual reality industry – specifically for developers who design the computer graphics that appear inside devices like the Oculus Rift. Just beyond the barfogenic zone lies the uncanny valley, says Prof Paul DiZio, a psychologist at Brandeis University in Waltham, Massachusetts, who has spent two decades investigating the problems we have adapting to virtual environments.

What does he mean? The uncanny valley describes the way that poorly animated near-human CGI animations prompt discomfort in viewers. While some have questioned whether the effect is as pronounced as has been claimed, many have reported experiencing it.

Indeed, the uncanny valley has concerned the games industry for a while. Using motion capture footage of actors rather than pure animation has helped to close the realism gap, but games designers and researchers alike have suggested that crossing the uncanny valley in games is still a way off. “I think every game out there right now has an uncanny valley problem,” Mark Daly of graphics chipmaker Nvidia told Slashdot in February.

And DiZio argues that as virtual reality worlds become more visceral – and, as users report, the feeling of deep immersion is now pronounced – the more likely they are to experience the unnerving sensations of the uncanny valley. “The more physically realistic the rendering becomes, the more icky the perception becomes,” he proposes.

What’s more, unlike movie-goers, gamers expect interaction from characters so unhuman traits are quickly noticed, says Dr Angela Tinwell, senior lecturer in games and creative technologies at the University of Bolton, UK, who co-authored a recent review of the uncanny valley problem in games. In the hyper-real world of virtual reality, she says, this expectation of real human interaction will be raised even further. “You feel you’re in that environment as a first person, integrating with characters. If you’re sitting physically back from the screen, it’s different,” she says.

So while virtual reality may have left the barforgenic zone, it’s possible we may be about to enter an altogether different – and more interesting – region of discomfort. The “creepogenic” zone perhaps?

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