When Virtual Reality Feels Real

Despite advances in computer graphics, few people would think virtual characters or objects are real. Yet placed in a virtual reality environment most people will interact with them as if they are really there. European researchers are finding out why. In trying to understand presence – the propensity of humans to respond to fake stimuli as if they are real – the researchers are not just gaining insights into how the human brain functions. They are also learning how to create more intense and realistic virtual experiences, opening the door to myriad applications for healthcare, training, social research and entertainment. Working in the EU-funded Presenccia project, researchers, drawn from fields as diverse as neuroscience, psychology, psychophysics, mechanical engineering and philosophy, conducted a variety of experiments to understand why humans interpret and respond to virtual stimuli the way they do and how those experiences can be made more intense. For one experiment they developed a virtual bar, which test subjects enter by donning a virtual reality (VR) headset or immersing themselves in a VR CAVE in which stereo images are projected onto the walls. As the virtual patrons socialise, drink and dance, a fire breaks out. Sometimes the virtual characters ignore it, sometimes they flee in panic. That in turn dictates how the real test subjects, immersed in the virtual environment, respond. In another instance, the researchers re-enacted controversial experiments conducted by American social psychologist Stanley Milgram in the 1960s that showed people’s propensity to follow orders even if they know what they are doing is wrong.

Instead of using a real actor, as Milgram did, the Presenccia team used a virtual character to which the test subject was instructed to give progressively more intense electric shocks whenever it answered questions incorrectly. The howls of pain and protest from the character, a virtual woman, increased as the experiment went on. Some of the test subjects felt so uncomfortable that they actually stopped participating and left the VR environment. Around half said they wanted to leave, but said they did not because they kept telling themselves it wasn’t real. All had physical reactions, measured by their skin conductivity, perspiration and heart rate, showing that, at a subconscious level, people’s responses are similar regardless of whether what they are experiencing is real or virtual. The plausibility of the events enhances the sense that what is happening is real. Plausibility, is therefore more important to presence than the quality of the graphics in a VR environment. For example, when a test subject was made to stand on the edge of a virtual pit, staring down at an 18-metre drop, their level of anxiety increased if they could see dynamically changing shadows and reflections of their virtual body even if the graphics were poor. In other experiments, the researchers made people believe that a virtual hand was their own – replicating in VR the so-called ‘rubber hand illusion’ – or that they were looking at themselves from another angle, creating a kind of out-of-body experience. In one trial, they even gave male test subjects a woman’s body. By understanding what makes people perceive virtual objects and experiences to be real, the researchers hope to create applications that could revolutionise certain psychiatric treatments. Patients with a fear of spiders or heights, for example, could be exposed to and helped to overcome their fears in virtual reality.

More information:

http://www.presenccia.org/

http://cordis.europa.eu/ictresults/index.cfm?section=news&tpl=article&BrowsingType=Features&ID=90561