Originally published August 24, 2007 at 12:00 AM | Page modified August 24, 2007 at 2:09 AM
Virtual goggles create out-of-body sensations
New research helps explain the sense people can experience of floating outside their bodies after traumatic events.
Los Angeles Times
Exploring the connection between our mental and physical perceptions of ourselves, scientists Thursday said they used virtual-reality goggles to induce out-of-body sensations in healthy volunteers.
In simple experiments carried out in Switzerland and England, test subjects looking at video images of themselves projected through the goggles reacted as if their own bodies had been touched when their virtual selves were stroked or poked.
Tricked by the illusion, participants reported feeling that their consciousness had drifted from their real bodies into their virtual ones.
The research helps explain the odd sense of floating outside their bodies that people sometimes experience after traumatic events.
Out-of-body experiences have been reported in cases in which a critical area of the brain is damaged, either from stroke, epilepsy or cancer.
The studies, published in the journal Science, "call into question the axiom that everything you are is anchored in your body," said Vilayanur Ramachandran, director of the center for the brain and cognition at the University of California, San Diego, who was not involved in the research.
Instead, Ramachandran said, "what you regard as you is really a transient construct created by the brain from multiple sensory sources."
When visual, tactile or other inputs don't line up, he said, the boundaries of self-perception shift.
Disorienting mismatch
In England, Dr. Henrik Ehrsson, of University College London's Institute of Neurology and the Karolinska Institute in Stockholm, asked 12 volunteers to wear virtual-reality goggles while they sat in an empty room. A camera behind each participant projected an image of their backs. Thus, the participants viewed their own backs from the perspective of someone sitting behind them.
Ehrsson stroked each participant's chest with a stick, carefully keeping his arm and the stick out of the camera's view. At the same time, he moved his other arm in front of the camera and dropped it down as if it were moving to rub the subject's virtual chest.
The subjects saw nothing happening to the image of themselves projected in the goggles. Yet, they could feel the stick on their own bodies. The result was a disorienting mismatch between the subject's tactile and visual senses.
![]()
When touched, participants reported they had the experience of drifting outside their own bodies toward the direction of the camera and viewing themselves from behind.
To test the illusion further, Ehrsson wielded a hammer, swinging it in front of the camera. Even though the participants felt nothing, they flinched and registered fear through sensors attached to their skin.
Ehrsson explained that he was interested in a person's perception of the "self."
"I'm interested in the question of why I feel that my self is located inside my physical body. How does my brain know that I am standing right here," he said.
This type of experiment could also lead to more practical applications in video games or remote surgery, Ehrsson said.
Virtual-reality goggles
In the Swiss experiment, Dr. Olaf Blanke, of École Polytechnique Fédérale de Lausanne, asked seven subjects to wear virtual-reality goggles while standing in an empty room.
A camera behind each person projected three-dimensional images in front of them. Thus, participants felt as if they were standing behind themselves.
When their backs were stroked in sync with the virtual image, participants reported feeling that their consciousness had been transported to the body in front of them.
The experiment was repeated with a virtual image of a human dummy and a large rectangular object. Participants' sense of self floated into the dummy but not into the object.
Blanke and colleagues said future experiments would look at the effect of disturbing a broader range of sensory perceptions, such as a sense of body position and balance.
The studies "allow us to understand how consciousness works," said Susana Martinez-Conde, a scientist at the Barrow Neurological Institute in Phoenix, who had no connection to the latest research. "It is what makes us who we are, what makes us human."
Material from The Associated Press and Reuters is included in this report.
Copyright © 2007 The Seattle Times Company
Service sector shrinks less than expected in June
UPDATE - 01:27 PM
Obama, Medvedev agree to deal to cut nuke weapons
Ousted Honduras leader blocked from return by air
Pakistan attack targets nuclear lab workers
UPDATE - 10:49 AM
Bankruptcy judge OKs GM sale plan, appeal looms

2009 fireworks time lapse
With strict parking rules enforced at this year's July 4th celebration on Wallingford Ave North, less cars and more spectators filled the streets.
Entertainment | Top Video | World | Offbeat Video | Sci-Tech
nwjobs

Post a comment

Michelle Goodman blogs about work/life balance.
Tax tips for new independent professionals
Post a comment
nwautos

Choosing a new sports car/coupe? Weigh the impact of your choice on your wallet and on the planet.
Post a comment
nwhomes

Find a new home or condo that fits your lifestyle.
Search New Developments
Builder Directory
- Seattle may allow homeowners to build backyard cottages
- Landmark Smith Tower mostly vacant
- Relative: Police say woman with McNair bought gun
- Property taxes: Appeals shoot up in King, Snohomish Counties
- Mariners Blog | What the Seattle Mariners learned on their road trip
- Palin links resignation to 'higher calling' and blasts media in Facebook posting
- Former NFL MVP McNair killed
- Hard times for tourist towns means good deals for travelers
- Tukwila residents rally against light-rail noise
- Brier Dudley | Brier Dudley | Learning hard lessons from Boeing giveaways
- Palin links resignation to 'higher calling' and blasts media in Facebook posting
211 - Tukwila residents rally against light-rail noise
140 - Tent City on campus: UW stalls decision
115 - What Mariners learned on this road trip
114 - Seattle may allow homeowners to build backyard cottages
86 - FBI denounces rumors: Palin not investigated
78 - Bicyclist fatally hit by SUV outside Bremerton
57 - 2 wounded in Central District drive-by shooting
57 - Bellevue ordinance would fine retailers for not collecting runaway shopping carts
56 - Mariners did their part, now they need help
51
- Property taxes: Appeals shoot up in King, Snohomish Counties
- Seattle may allow homeowners to build backyard cottages
- Researchers stunned by inmates' success raising endangered frogs
- Hard times for tourist towns means good deals for travelers
- Landmark Smith Tower mostly vacant
- 250 gather in field near Twisp for fairy congress
- New laws help tenants evicted due to foreclosure
- Plasma and LCD beware; OLED screens ready to go mainstream
- The People's Pharmacy | Estrogen mimicker found in sunscreen
- Seattle safety project: A snake shelter on Beacon Hill





