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Virtual reality: Five key principles to avoid motion sickness by Guillaume Jegou

Research on virtual reality has had the teams of the Human Factors Technologies Lab working for years, particularly on the phenomenon of motion sickness. Guillaume Jégou, Head of the Lab, tells us more about their work on this issue.

Can you explain to us what motion sickness is?

Motion sickness is a disorder that occurs when there is a discrepancy between what the brain interprets, particularly through vision, and the perception of the inner ear. It is also known as kinetosis or travel sickness. This sensory conflict is generally characterized by symptoms of discomfort, eye strain, disorientation, and nausea. In a virtual reality experience, the user's perceptions are artificially stimulated, and in some cases, motion sickness may occur. In particular, it's correlated with the characteristics of the content and terminals. Today, virtual reality is becoming increasingly accessible to the public, thanks to low-cost terminals and the wealth of content available on the Internet. This democratization of virtual reality is a good thing, in that it enables the opening of new markets, but only if experience doesn't suffer. In fact, although there are few consequences for a mini-app that lasts several seconds, it is hard to see why anyone would spend several hours in a situation they find uncomfortable. Ultimately, it's essential to offer concrete solutions to this motion sickness problem, so that the promises of virtual reality can be kept!

What ideas are your teams currently working on in order to solve this problems?

One of the approaches we've adopted is detecting physiological discomfort in order to be able to take it into account in real time. We're currently working on biosensor-based automatic detection algorithms. These sensors can be used to capture various psychophysiological signals, and after processing, to categorize the comfort of usage, and to detect the effects of motion sickness before they start to cause trouble for the user. This detection step, which draws on machine learning, is an essential point, because it makes it possible to act preventively or correctively. The same approach can also be used to qualify one's cognitive or emotional state in real time, such as stress, cognitive load, or engagement.

Furthermore, to limit the phenomenon of motion sickness, several factors may be taken into account. The first is hardware performance to avoid the problem of lag, which can be a major cause of discomfort, or even queasiness. Second, it's essential to work on appropriate content, in an approach that combines design with knowledge of human perception. From this standpoint, some "tips" are beneficial to test, such as adding stable visual markers to the content or making a relevant use of peripherical vision during some movements. Likewise, a representation of one's own body may serve as one of these markers. If you let users see their own hands, for example, it's possible to limit the uneasiness of perceiving oneself as a purely phantom being. We also believe greatly in multi-user experience. In addition to making the experience collaborative and engaging, it gives the user an additional visual marker. Collaboration also makes it possible to be a protagonist through interaction, not just a simple spectator to the experience. Lastly, to limit physiological discomfort, it's essential to pay attention to the consistency between the motion of one's own body and its translation into virtual reality. This is why we're now working mainly on one-to-one scale. That means that when the user moves a meter within the content, they move a meter within reality, with 6 degrees of freedom (6DOF).

More generally speaking, what properties should any virtual reality experience offer?

The main property of a successful virtual reality experience is Presence, which is the authentic feeling of being in a place other than where you physically are. The science fiction author Arthur C. Clarke said: "Any sufficiently advanced technology is indistinguishable from magic". This could be a summation of the ideal virtual reality experience: Being transported, as if by magic, to another world, while ignoring the technological environment needed to get there.  For this to work, acceptability is an issue that must be dealt with on several levels.

Cognitive acceptability is unique to each user, but will be heavily tied to the believability of the virtual experience. There are general principles of action-reaction that must be consistent to the user. It's helpful to suggest natural interactions between the user and the content in order to immediately plunge them into "deep" immersion. In the field of cognitive sciences, we're also working on designing smarter content, based on behavioral artificial intelligence architectures. To bolster believability, not everything can be scripted; some behaviors of virtual entities should be emergent, meaning that they arise from certain general properties but are not foreseeable. For example, a school of fish or a marine mammal will change its behavior dynamically, with no pre-set script, based on the interactions with the user (a compromise between fear and curiosity). This way, one can relive the same scene multiple times, with a fresh experience each time. Finally, social acceptability is critical. This is because social depictions of a technology, and particularly a disruptive technology like virtual reality, may be powerful sources of appeal or rejection. There are many underlying issues about dependency, addiction, and psycho-pathological risks, but also many expectations about the possibilities of deep immersion in terms of accessing culture, training, recreation, social media, simulating new worlds, medicine, and more. Between fantasy and reality, these representations can be studies to better design technologies, products, and services and act responsibly.

What virtual reality projects are you currently working on at b<>com?

In late April, we're presenting a preview at NAB Show of content created in partnership with Océanopolis, the ocean discovery park in Brest, France. This is an edutainment project that will enable Océanopolis visitors to explore the seafloor using virtual reality. The experience will offer viewers the chance to interact immersively with other users and have total freedom of movement. It will also be possible to interact naturally with a smart environment populated with marine mammals and fish brought to life by artificial intelligence, and to witness an improved representation of oneself and others.  A test phase will also be carried out among Océanopolis visitors this summer, and will enable our teams to get user feedback to improve the experience and confirm the technological choices. All of these issues are being handled in a multidisciplinary way at b<>com, and are making use of many different professions: Designers, cognitive science and artificial intelligence experts, R&D engineers, ocean scientists, and more.