When you're a kid, everything seems huge. Teachers tower over you; playgrounds stretch on to infinity. Now, researchers have found a way to make grownups feel the same way. By placing volunteers in virtual reality, scientists are helping adults see the world through the eyes of a child.
Virtual reality is more than an illusion. To enter it, people put on full-body suits that track their movements and goggles that display an artificial world in which they have a virtual body. If their virtual and real movements sync up, their computer-generated bodies start to seem real. Previous research has shown that subjects begin to feel like their body has changed into the simulated figure, even if it is different from their own body; volunteers placed into the body of a teenage girl, for example, "felt it" when her mother slapped her computer-generated representation. But scientists did not know how this virtual body "ownership" affected people's perception of the world around them and whether this could help people relate with others unlike themselves.
To find out, computer scientist Mel Slater of the University of Barcelona in Spain and colleagues placed adult volunteers into a virtual outdoor scene in which they did not have a computer-generated body. They were asked to estimate the sizes of six different cubes within the scene and were told whether their guesses were too big, too small, or correct. Later, they reentered the scene and repeated the exercise with three cubes, without feedback from the researchers. Their size estimates without a virtual body were noted.
After this training exercise, the researchers placed the subjects in two different avatars, virtual characters controlled by participants. One was a 4-year-old child of the same gender as the participant. The other was an adult who was the same height as the child. While standing in a virtual living room, the participants again gauged the size of the cubes without feedback.
Adults stated that they felt the two virtual bodies were equally real, and they misjudged object size in both avatars. But those in the child avatar rated the cubes about twice as large, on average, as did those in the adult bodies, Slater's team reports online today in the Proceedings of the National Academy of Sciences.
In a test after the simulation, participants who had been in the virtual child body were quicker to mischaracterize themselves with childlike traits than their actual ones. For example, someone who had embodied the virtual 4-year-old was more likely to identify themselves as attending primary school than someone who had embodied the scaled-down adult.
When movements of the virtual and real bodies did not match, participants no longer felt their avatars were real. They still overestimated the size of the cubes, but there were no differences between the adult and child avatars. The researchers conclude that the type of avatar can affect how people see their virtual environment only if they feel connected with their virtual body.
Slater notes that the experimental setup in this study could be used to help people empathize with others who are unlike themselves, for example by putting criminal offenders in the virtual body of the victim at the crime scene to help them see the event from the other perspective.
The study demonstrates that we may need to think harder about the implications of spending time in a digital world, says cognitive psychologist Jeremy Bailenson of Stanford University in California. He describes a hypothetical danger of Google Glass, a pair of glasses that gives users hands-free access to the Internet. "If I'm using Google Glass and I'm in the avatar of a child, I may not be able to cross the street in the right manner because I'm seeing objects as a different size than they actually are out in nature."