08 December 2007

Touch | Sight| Relocated Self

By deliberately scrambling a person's visual and tactile senses, it is possible for scientists to give them an out-of-body experience.

Most popular of this type of perceptual illusion is the "Rubber Hand Illusion."

New Scientist cites the next demonstration, also performed by UCL's Henrik Ehrsson. Cameras and projections are set up to confuse subjects into experiencing that they are standing somewhere else in the room, reinforcing the idea that peoples' perception of 'self' is tightly bound to how information is processed by the senses.

In these experiments, the sense of touch is synchronized with visual movement. These perceptions are put in conflict with where the synchronization is happening. The brain defaults to vision, which is the most informationally rich sensory modality. As the self is no longer 'within its borders', subjects feel like they're having an out-of-body experience.

Here's a DIY version, brought to you from the guys at Mind Hacks:
"Sit at a table with a friend at your side. Put one hand on your knee, out of sight under the table. Your friend’s job is to tap, touch, and stoke your hidden hand and—with identical movements using her other hand—to tap the top of the table directly above. Do this for a couple of minutes. It helps if you concentrate on the table where your friend is touching, and it's important you don't get hints of how your friend is touching your hidden hand. The more irregular the pattern and the better synchronized the movements on your hand and on the table, the greater the chance this will work for you. About 50% of people begin to feel as if the tapping sensation is arising from the table, where they can see the tapping happening before their very eyes. If you're lucky, the simultaneous touching and visual input have led the table to be incorporated into your body image."

Beyond the practical applications of creating more realistic avatars in virtual reality games, and for doctors' performing remote surgery, these experiments explore the question, 'Why do we feel we own our body?' They indicates that "self" is closely tied to a "within-body" position, which is dependent on information from the senses. Swiss researcher Olaf Blanke concludes, "We look at 'self' with regard to spatial characteristics, and maybe they form the basis upon which self-consciousness has evolved."

Evolving Perception: Tele-Synesthesia and Touch Technology

via Mind Hacks

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