Webcomic xckd once did a take on a phenomenon most of us have experienced: the perceived difference between the actual size of a place and our childhood memories. The same playground that felt like an entire country to our grade-school selves feels smaller, even cramped, to our adult vantage points. A recent study by scientists at the University of Barcelona, however, managed to induce that feeling in reverse, making adults feel childlike again through the use of virtual reality (VR).
Mel Slater and colleagues outfitted their participants with motion-capture suits, the same technology used to create movie performances like Andy Serkis’s Gollum in “The Lord of the Rings: The Fellowship of the Ring.” The movements of each subject were then scaled down and mapped to a virtual model of a four-year-old, which the participant could see in a virtual “mirror” while wearing a head mounted display. After adapting to the movements of this virtual body, the participants were asked to estimate the sizes of a number of cubes in the virtual environment, and those inhabiting the child avatars nearly doubled the size of their guesses over a control group of subjects inhabiting adult avatars of the same height. Additionally, an implicit association test conducted after the VR experiment showed that participants in the child group had subconsciously begun to identify themselves with traditionally childlike traits and images.
Previous research has also established a physical link between virtual and real-world responses. An earlier study by Slater’s group had participants experience a virtual slap to the face, which generated the very real physiological response of reduced heart rate. A similar experience can be generated with a much lower-tech trick, the “rubber hand illusion.” In this setup, the participant’s real hand is placed under a realistic false hand that is “connected” through a sleeve to the rest of the body. Watching the false hand get stroked or hit generates a real sensation, and functional magnetic resonance imagining (fMRI) of the brain during these experiments has shown increased activity in regions associated with integrating sense information. As neuroscientist Arvid Gutersam explains, “It therefore seems as if these areas of the brain automatically associate the sight from the brush moving in empty space with the touch felt on the real hand, leading to the bizarre consequence that one feels touch in midair and perceive having an invisible hand in this location.”
True VR systems are likely to remain in the laboratory for some time due to their expense, but new technology like Google Glass may open at least some of their possibilities to a wider audience. Users should remain mindful of how immersion in a virtual world can have effects in the real one; in the case of Slater’s experiment, it’s possible that adults who have recently spent time in a child’s body might misjudge distances while driving and have an increased accident rate. Yet there are many possibilities for productive use: for example, the military has studied VR as a way to treat soldiers suffering from PTSD. The interface between real and virtual experience remains a relatively unexplored territory, but it is surely a fascinating one.