Body-Swap Illusion Tricks Mind

A New Study Simulates Out-Of-Body Experiences Using Virtual Reality Goggles

(AP)  Shaking hands with yourself is an amusing out-of-body experience. The illusion of having your stomach slashed with a kitchen knife, not so much.

Both sensations, however, felt real to most participants in a Swedish science project exploring how people can be tricked into the false perception of owning another body.

In a study presented Tuesday, neuroscientists at Stockholm's renowned Karolinska Institute show how they got volunteers wearing virtual reality goggles to experience the illusion of swapping bodies with a mannequin and a real person.

"We were interested in a classical question that philosophers and psychologists have discussed for centuries: why we feel that the self is in our bodies," project leader Henrik Ehrsson said. "To study this scientifically we've used tricks, perceptual illusions."

It sounded intriguing enough for me to try it, though entering the laboratory on Monday, I was having second thoughts.

The first props I saw were two kitchen knives, three naked dummies and a prosthetic hand sticking out from behind a curtain.

"You have the right to say stop at anytime if you feel uncomfortable," said Ehrsson's colleague, Valeria Petkova, as she rubbed my left hand with electrolytic gel and attached electrodes to the middle and index fingers.

She assured me I was not in any danger. Still, a nervous tingle rushed through my body as she placed the headset over my eyes.

In the first experiment, the goggles were hooked up to CCTV cameras fitted to the head of a male mannequin, staring down at its feet. Through the headset I saw a grainy image of the dummy's plastic torso. I tilted my head down to create the sensation I was looking down at my own body.

At that point, it didn't feel very real. But when Petkova simultaneously brushed markers against my belly and that of the mannequin, the effect started setting in. As my brain processed the visual and tactile signals, I had a growing impression that the mannequin's body was my own.

That was good fun, until the gleaming blade of a bread knife entered my field of vision. Petkova slid it across the dummy's stomach, sending shivers down my spine and a pulse of anxiety through the electrodes. My heightened stress level was illustrated by a spike in a computer diagram shown to me after the experiment.

"Approximately 70-80 percent of the people experience the illusion very strongly," Petkova said.

Apparently, I was one of them.

The second experiment was more benign. This time my headset was connected to cameras mounted on a round hat that Petkova was wearing. We faced each other, extended our right arms and shook hands.

Now that was weird: I was supposed to have the sensation of shaking hands with myself. The illusion wasn't perfect as I couldn't quite recognize Petkova's grip as my own, even though that's what the goggles meant to make me believe.

Perhaps the session was too short. The actual study, in which 87 volunteers participated, consisted of repeated sessions that gradually provided more accurate data. The results were published in PLoS One, the online journal of the Public Library of Science.

The principle finding was that under certain conditions a person can perceive another body as his or her own, even if it is of an opposite gender or an artificial body.

"These findings are of fundamental importance because they identify the perceptual processes that make us feel that we own our entire body," the study said.

Ehrsson said the study built on a previous experiment known as the "rubber hand illusion" in which participants were manipulated to experience a rubber hand as their own.

Charles Spence, a professor of experimental psychology at the University of Oxford, said the Karolinska study was a "step up" from other research on the subject.

"This goes beyond other recent studies, where you've taken ownership of rubber hands and rubber legs," said Spence, who was not involved with the study.

His only concern was whether there might be any lasting effect on participants.

"The questions is what happens if you did it much longer? If you were in there for days and weeks. Would it be like something out of Total Recall?" Spence said, referring to the 1990 Arnold Schwarzenegger science fiction movie about a virtual vacation that turns into a nightmare.

Ehrsson suggested the findings could be applied in research on body image disorders by exploring how people become satisfied or dissatisfied with their bodies. Another possible application could be developing more advanced versions of computer games such as Second Life, he said.

"It could lead to the next generation of virtual reality applications in games, where people have the full-blown experience of being the avatar," Ehrsson said.

[sophroniscus]

Where can I sign up?

[mrmeatspin]

my God!! I dont think our human mind is psychologically ready to keep up with advancements in science.

we should be very very carefull what we wish for.

[rf35]

I don''t even experience my OWN body as mine. Maybe we''re already in a virtual reality world.
Posted by brucestevens

Welcome to the Matrix.

[silverstar06]

Why, with my perfect sounding English and all, you''da never thought I have a foreign accent! Is that out of body or just stupid?

[toolmangler-2009]

My cousin is employed at the Pentagon and saw the Plane hit the building with his own eyes, But when he tells some people they refuse to believe him. Just like Holocaust survivors are called liars by certain Non-Jewish peoples in the mid east

[remarkor]

Actually, the porno industry may be the first to use this, but not the last. Who do you think pioneered vhs movie rentals, and then online commerce?

[swingset4u]

...most of you probally still believe a 757 can enter the Pentagon and only leave a 16 ft diameter hole...

Posted by skarrzpapi

I like your post up until this paragraph... The hole I saw was a lot larger than 16ft in diameter. The initial impact, with no explosion would create such a hole of 16ft. Heres why... The exterior height of the fuselage is only 12ft 4in. The interior is only 11ft 7in. So the initial hole would ONLY be as big as the projectile itself. But with the following explosion and the breakaway of stressed matter a hole the size of 16ft in diameter is completely plausible.

[swingset4u]

Another worthwhile project from the science community...whatever. If these bozos were in the US, they''''d probably be looking for bailout money to continue these ridiculous experiments.

Posted by heathme2003

The mind is a terrible thing to waste... on you....

[swingset4u]

Face it, what man wouldn''''t pay $500 or $1000, or more, for a tech solution that would make him believe he was having se*x with a supermodel?

Posted by AnitaY417

Okay I had to make a couple of corrections to your post. The corrections are capped.

Face it, what man OR WOMAN wouldn''''t pay $500 or $1000, or more, for a tech solution that would make him OR HER believe he OR SHE was having se*x with a supermodel?

[skarrzpapi]

i guess most of you miss the philosphical implications of these experiments...and physiological as well...pay attention...try opening a book and reading about the mind/body duality...as an American it saddens me to see so many think this is a pointless experiment..no wonder our kids lag so far behind in education and abilities vs the rest of the industrialized world...try turning off your TV''s and reading..or better yet..turn off your TV''s and make ur kids....ahh forget it...most of you probally still believe a 757 can enter the Pentagon and only leave a 16 ft diameter hole...WAKE-UP AMERICA!!!!

[rozzzzzzy]

Would this be useful for amputees with phantom pain? There was a study that used mirrors to trick an amputees mind into thinking a mirror image of their remaining arm was the missing arm, so they could move the "missing arm", flexing it to alleviate the pain.

[evian_ycnan]

You say "Potato." I say "Vodka." Enough Grey Goose and anyone can have an out-of-body experience and for less than $40.

Ha! I laugh at their illusion of having one''s stomach slice with a knife! Ten martinis and you can have illusion of throwing up your shoes.

[heathme2003]

Another worthwhile project from the science community...whatever. If these bozos were in the US, they''d probably be looking for bailout money to continue these ridiculous experiments.

[torva-2009]

I bet there is going to be a lot money made in the porno industry with this new technology!

[torva-2009]

Just because something is way over your head doesn''''t mean it''''s not news worthy...you probably think Palin is great speaker. Idiot.

Posted by ThinTheHerd2 at 02:45 PM : Dec 02, 2008

Yeah...but she can field dress an elephant carcass in sixty seconds, you betcha she can!

[pat1967-2009]

ThinTheHerd2

You betcha! Lol!

[dbstevens]

I don''t even experience my OWN body as mine. Maybe we''re already in a virtual reality world.

It amazes me how some people will spend so much time and money on stuff that is easy to figure out otherwise...this isn''t rocket science.