In the virtual world, seeing is no longer just believing—it's being. In a new study, volunteers donned virtual reality goggles that put them in the body of a teenage girl in a virtual living room. The girl's mother stroked her on the shoulder while researchers simultaneously stroked the volunteers. Then, suddenly, the virtual mother slapped the girl—and the volunteers "felt" it. Their heart rates rapidly decelerated, a normal, initial response to a threat, even though there was no slap to their real faces. This is a sign that the subjects had begun to "own" their virtual body, the team reports  today in PLoS ONE. The effect was much more powerful if the volunteers had a first-person perspective, looking out of the eyes of the girl, rather than hovering above her in a third-person perspective. As virtual games become more immersive, designers may have to keep health risks in mind.
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