The concept of swapping our body with that of another person may sound science-fictional, but it is actually the latest subject for discussion in the scientific community. A recent experiment conducted by Swedish researchers from the Department of Neuroscience at the Karolinska Institutet in Stockholm, Sweden, revealed that by manipulating the visual perspective of a person, one could experience being in someone else’s body.

The study revolves around one essential question that psychologists found hard to answer: how come we are able to perceive our body as part of ourselves? According to researchers, we experience our body as our own as an adaptive function, possibly correlated with the problem of localizing and identifying oneself in the sensory environment.

This scenario is however broken by some pathological cases, in which frontal and parietal lobe conditions could trigger the failure to recognize our body as our own. Furthermore, damage to frontal, parietal or temporal regions has also been associated with being outside the body, the Swedish researchers explained.

As they attempted to better understand our centre of awareness, the researchers realized that focusing on bodily self-perception will provide them with invaluable information. In order to do this, they’ve conducted several experiments in which they demonstrated that it is possible to experience the illusion of ownership of a body other than our own.

In one experiment, the scientists used a life-sized mannequin equipped with two CCTV cameras which recorded the events from the mannequin’s eyes perspective, and a set of head mounted displays (also connected to cameras), worn by the participants.

The participants were asked to tilt their heads down as if they were looking at their own bodies, but in fact, the headset created the illusion that they were looking at the mannequin’s body. Experimenting with simultaneous strokes on the mannequin and the participant’s bodies caused participants to perceive the mannequin’s body as their own.

A second experiment focused on the psychological evidence for owning a new body, based on threatening the artificial body with a knife, which caused the participants to respond as if the mannequin’s body was in fact their own.

But the most exciting experiment of all was the body-swap experience, in which a participant and an experimenter stood face to face, wearing the specially designed, camera-equipped helmets. They were asked to hold each other’s hand as if to shake it, and repeatedly squeeze each other’s hand for two minutes. Both of them were able to see their bodies from the shoulders to slightly above the knees.

The conclusions of the experiment were amazing, with the participants describing the sensation of the squeezing of the hands as if it had originated from the experimenter, and not from their own hand.

The researchers explained that the body-swap illusion was possible even if the mannequin or the other person in the experiment was not the same gender as the participant.

The conclusion of the experiment was that matching the multisensory and motor signals from the first person perspective was enough to create the sense of ownership of one’s body, thus opposing the theory according to which body perception is a direct result of bottom-up processing of afferent signals from muscles, joints and skin. The findings are detailed this week in PLoS One.