The power of invisibility has long fascinated man and inspired the works of many great authors and philosophers. In a study from Sweden's Karolinska Institutet, a team of neuroscientists now reports a perceptual illusion of having an invisible body, and show that the feeling of invisibility changes our physical stress response in challenging social situations. The history of literature features many well-known narrations of invisibility and its effect on the human mind, such as the myth of Gyges' ring in Plato's dialogue The Republic and the science fiction novel The Invisible Man by H.G. Wells. Recent advances in materials science have shown that invisibility cloaking of large-scale objects, such as a human body, might be possible in the not-so-distant future; however, it remains unknown how invisibility would affect our brain and body perception. In an article in the journal Scientific Reports, the researchers describe a perceptual illusion of having an invisible body. The experiment involves the participant standing up and wearing a set of head-mounted displays. The participant is then asked to look down at her body, but instead of her real body she sees empty space. To evoke the feeling of having an invisible body, the scientist touches the participant's body in various locations with a large paintbrush while, with another paintbrush held in the other hand, exactly imitating the movements in mid-air in full view of the participant.
“Within less than a minute, the majority of the participants started to transfer the sensation of touch to the portion of empty space where they saw the paintbrush move and experienced an invisible body in that position,” says Arvid Guterstam, lead author of the present study.