Virtual reality messes with your brain -- and it gets especially weird when neuroscientists use it to scramble your illusion of self. A new VR study uses a few simple tricks, like a paintbrush, to fool the brain into thinking the body has disappeared.
The study published in Scientific Reports riffs on an old trick in neuroscience: the rubber hand illusion. If you see a rubber hand being stroked and feel your hand being stroked in the same way, your brain unconsciously begins to take ownership of that hand. You might, for example, wince to see the rubber hand whacked with hammer.
In virtual reality, the rubber illusion can a little more sophisticated. Scientists at Karolinska Institutet in Sweden put 125 volunteers inside virtual reality, where if they looked down at their bodies, they saw nothing. Then they poked their chests with a paintbrush while the blank space of their "invisible body" in VR was also poked with a paintbrush. The combination of feeling and seeing was enough to get most participants to accept the illusion.
How? Well, if the researchers changed the virtual paintbrush into a virtual knife, the volunteers unconsciously reacted in fear. Their bodies were invisible, but the threat was still "real". Their hearts raced and their skin got sweaty. In a follow-up experiment, the participants saw a large crowd of people staring back at them -- a normally stressful situation. But those who believed their bodies were invisible felt less social anxiety.
As VR has improved, psychologists have been using it to probe how our brains perceive of reality. Our unconscious brains are actually pretty easily fooled, but that also means VR could be used fool it in productive ways. For example, as this study demonstrates, maybe virtual invisibility can help people deal with social anxiety. Future therapy might just comes with a dose of the virtual.
Picture: Study co-author Zakaryah Abdulkarim (middle) creates the invisible body illusion on a participant (left) wearing a set of head-mounted displays connected to a pair of cameras (right). Credit: Staffan Larsson