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Manipulating Bodily Self-Consciousness

 

 
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Humans normally experience the conscious self as localized within their bodily borders. This spatial unity may break down in certain neurological conditions such as out-of-body experiences, leading to a striking disturbance of bodily self-consciousness. On the basis of these clinical data, we designed an experiment that uses conflicting visual-somatosensory input in virtual reality to disrupt […]

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Posted August 26, 2007 by thomasr

 
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virtualreality.jpegHumans normally experience the conscious self as localized within their bodily borders. This spatial unity may break down in certain neurological conditions such as out-of-body experiences, leading to a striking disturbance of bodily self-consciousness.

On the basis of these clinical data, we designed an experiment that uses conflicting visual-somatosensory input in virtual reality to disrupt the spatial unity between the self and the body. We found that during multisensory conflict, participants felt as if a virtual body seen in front of them was their own body and mislocalized themselves toward the virtual body, to a position outside their bodily borders.

Our results indicate that spatial unity and bodily self-consciousness can be studied experimentally and are based on multisensory and cognitive processing of bodily information.

Video Ergo Sum: Manipulating Bodily Self-Consciousness

Lenggenhager et al. in Science


thomasr

 


4 Comments


  1.  

    The experiments reported by Lenggenhager et al and by Ehrsson in Science tell us something very important about the nature of the self as a part of the cognitive brain. First, they demonstrate that our sense of self-location can be dissociated from our actual body location. Second, they demonstrate that where we believe we are located in space is more strongly influenced by visual information in 3D space than by somatosensory information. When the phenomenal experience of events in egocentric space is uncoupled from the real world by virtual reality (VR) techniques, self-location becomes consistent with the VR world in which the “touch” occurred rather than the real world in which the touch occurred. So if our sense of self location is not necessarily anchored within the envelope of our physical body, where in the world is it anchored? My answer is that it is anchored at the origin of the egocentric space of our own virtual world. This virtual world is in the brain and is constituted by the neuronal structure and dynamics of what I call the retinoid system.

    See: http://people.umass.edu/trehub/YCCOG828%20copy.pdf

    When the virtual world of the retinoid system is tricked by the substitution of contrived visual input instead of veridical input, the self is naturally located at an egocentric coordinate consistent with the layout of objects and events (e.g., touch) within that other virtual world. It seems to me that this argues against Metzinger’s claim that no such thing as a self exists.

    Arnold Trehub




  2.  

    How could the experiment work with someone that is blind? How does a blind person experience bodily self-consciousness? Which senses of a blind person could be manipulated in order for them to have an Out of Body Experience?




  3.  

    Maybe, a blind person can experience an out of body experience by rapid acceleration/deceleration in the vertical and horizontal plane causing a disruption in the normal functioning of the vestibulo-choclear system. See, Olaf Blanke studies on “out of body experience” (OBE), for a better response.




  4.  

    Josh raises some interesting questions. According to the retinoid theory, a blind person experiences bodily self-consciousness the same as a sighted person. Like a sighted person, the brain of a blind person is innately endowed with a retinoid system that provides an internal neuronal representation of the person’s egocentric space including a compact representation the self-locus at its egocentric spatial origin. The difference, of course, is that in the blind no visual excitation projects into 3D retinoid space. Aside from this difference, all other interoceptive and exteroceptive patterns of bodily stimulation can be projected into their proper spatiotopic coordinates within retinoid space.

    It might be possible to manipulate kinesthetic and somesthetic events to induce an out-of-body experience (OOBE) in the blind. The following experiment occurs to me. Suppose a blind person (S) stands behind the back of a dummy torso clothed in the same fabric worn by S. S is instructed to reach out and touch something in front. Beneath the fabric on the mannequin’s back is a grid of pressure-sensitive sensors that activate a similar grid of electro-mechanical prodders arranged to touch the back of S at the same moment and at the same relative bodily location as S reaches out and touches the back of the dummy. Under these conditions, one might expect a blind person to mislocalize his self to the position of the “body” at some distance in front of his actual bodily location. It is also possible that S would have the weird feeling of reaching in front to touch his own back.

    Does anyone know if such an experiment has been done? Any thoughts on the likelihood of an OOBE under these conditions?

    Arnold Trehub





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