Expérience incarnation d

"Virtual reality is a powerful experience"

It is a research project that takes place in an industrial environment. Using a magnetic clamp, the participant takes a metal ingot from a crate and deposits it on a tray that arrives in front of him through a conveyor belt. The place where to place the object is drawn on the board. Then it is necessary to press a button and a heavy press crushes the ingot. And the task repeats itself, immutable. Suddenly, the press rushes and suddenly crashes, in a huge noise, on the hands of the participant !

Let us be reassured: this one emerges unscathed. The experience is indeed virtual. Wearing an HTC Vive headset and equipped with controllers allowing him to act in subjective view, the participant is not injured, struck or even touched by anything. However, when he resumes his virtual task after the incident, he multiplies the cautious, hesitant gestures, his hand hastens to withdraw from the danger zone after the deposit of a new ingot, as evidenced by the visual observation but also the measurements made. So many elements that betray an apprehension to be caught again by the press.

Led by researcher Rebecca Fribourg at Inria Rennes, this project is the subject of an article this week. It shows that a situation of danger does not break the feeling of embodiment of a virtual character, even if a part of the sensory signals (here touch) proves to the user that everything is an illusion. It is thus possible to sensitize someone to a danger through virtual devices, such as in motor rehabilitation (with the risk of falling) or in the framework of industrial training. The fact that the user does not physically experience the consequences of his mistakes will not prevent him from paying attention and therefore progress.

This research extends others, just as troubling, carried out by Inria’s Hybrid team, such as the “sixth finger” or coincarnation. They are part of a technological context that, in recent years, has contributed to the development of work on virtual embodiment. Rebecca Fribourg and Antoine Lecuyer, head of the team and author of a book on the subject (Our brain is a superhero, HumenSciences éditions, 2019) review their research.

Science and the Future: In virtual reality, there have already been works exposing participants to stress or danger. What did you want to study through this project ?

Rebecca Fribourg : In virtual reality, seeing how users appropriate their virtual bodies is often subjective data. There we observe objective data: reactions to a virtual danger. This introduction of a virtual danger is often used to verify the incarnation. But the impact of a dangerous situation on this incarnation had never been measured. But one could wonder if the absence of sensory feedback did not risk breaking the virtual incarnation. In our scenario, after the press has crushed the virtual hand, we see that the participants continue their task with stress, fear of danger, a repeated threat and adapt their behavior while their real hand has nothing. The feeling of embodiment is not altered.

Antoine Lecuyer : The measure of the incarnation is a paradox because asking someone, in the process of experience, if he feels well embodied in a virtual body risks breaking the incarnation. And answering an afterthought questionnaire, by definition, happens out of experience. However, we can observe data such as sweating, heart rate, neurological markers, but this will concern what is called agency [le sentiment de pouvoir agir, ndlr], which is only one dimension of the incarnation. How people adapt their voice according to the avatar can also serve as a real-time measure.

Along the same lines, your book describes an immersive installation where users are given virtual shadows that don’t match them. You tell that, spontaneously, people begin to behave according to the image that the shadow returns of themselves.

Anatole Lecuyer : Absolutely. It was on the fringes of the experience itself, but with the shadow of Lucky Luke, we want to wear his hand to his hat. I also had a ponytail shadow and tried to touch it. That is, at some point, one is ready to consider the possibility of being something else. This project took place in a CELLAR, with the immersive environment projected on walls. We wanted to see if the virtual incarnation could take place outside of a headset [où l’illusion est a priori plus facile à créer car l’utilisateur ne voit pas son corps réel, ndlr]. The answer is partially yes.

In the spring of 2020, several researchers, from the academic and industrial world, published a text arguing for the study of possible negative effects of virtual reality, in particular because we risk seeing one day arrive unhealthy immersions. What is known about this?

Anatole Lécuyer : Many studies show that there is an effect on behavior. This is the so-called Proteus effect, identified by researchers from Stanford University (USA) : our behavior changes according to our avatar. Be careful, it is to be taken with tweezers, it is only a trend. But this raises questions.

Rebecca Fribourg : It is above all the notion of long-term effects that deserves to be studied. Because indeed, virtual reality is a powerful experience, more than being in front of a screen for a video game for example.

At the University of Barcelona, researcher Mel Slater has designed a psychotherapeutic immersion, another tackles the fear of death, a third is used on men convicted of domestic violence by placing them in the role of a victim facing an aggressive husband… Is it still experimental or can VR be part of a care program ?

Anatole Lécuyer : Clearly, virtual reality has become a therapeutic tool : in the treatment of phobias, in so-called cognitive-behavioral therapies. People can be exposed to anxiety elements, put them in uncomfortable situations more easily. Treat fear of public speaking, for example.

Rebecca Fribourg : Laboratories are really developing therapies, as in the United States with veterans suffering from post-traumatic stress disorder. Virtual incarnation has effects full of potential.

What technical advances do we owe to all these developments and perspectives ?

Anatole Lécuyer : The technological context has changed with the arrival of visiocasques. Their applications led to the question of how to represent the user in the virtual environment, which led to the development of research on avatars. Both technically and psychologically.

We are all a little amazed, in the scientific community, by what these projects reveal about our psychological plasticity. Virtual reality is both a way to study certain phenomena but in addition, it allows to do things that would not be possible in the real world. Like adding a sixth finger to a hand.

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