Scientists at the Brain, Body, and Self Laboratory at Karolinska Institutet in Sweden outfitted pairs of friends with video goggles so they saw things from each other's point of view. "To further the illusion," reports Science Daily, "they applied simultaneous touches to both participants on corresponding body parts so they could also feel what they saw in the goggles." They discovered that the participants in the study "tended to rate themselves as more similar to the friend whose body they were in."
After just a few moments, the illusion generally worked; to show that it did, the researchers threatened the friend's body with a prop knife and found that the participant broke out into a sweat as if they were the one being threatened. "Body swapping is not a domain reserved for science fiction movies anymore," Tacikowski says.
Participants were only made to feel like they had "woken up in someone else's body" for a brief period of time, but that was long enough to significantly alter their self-perception. Before the body swap, participants rated their friends on traits like talkativeness, cheerfulness, independence, and confidence. Compared to this baseline, during the swap, they tended to rate themselves as more similar to the friend whose body they were in.