Hack 64. Mold Your Body Schema (2)
One easy way of moving your hands together is to run a curtain rail under the mirror, if you have one handy, and place each hand on a curtain ring (this is what I’m doing in Figure 6-2). Move your hands toward and away from the mirror for 30 seconds, until your brain has confused your right hand and your reflected left hand in the mirrorthen release the curtain ring from your right hand. You can feel the ring has gone, but in the mirror it looks as though you’re still holding it. To me, the disconnect felt like pins and needles, all through my right hand.
Alternatively, you can manipulate your body schema into incorporating a table as part of yourself.1 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 stroke your hidden hand andwith identical movements using her other handto 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.
6.4.2. How It Works
These techniques provide conflicting touch and visual feedback, making it difficult to maintain a consistent impression of exactly where body parts are located in space. They’re similar to the crossed hands illusion [Hack #63], in which twisting your hands generates visual feedback contradictory to your body schema. In the crossed hands illusion, this leads to movement errors, and in the preceding techniques leads to the sense of being momentarily disconnected from our own movements.
Some of our best information on the body schema has been from patients who have had limbs amputated. More than 90% of amputees with reporting an experience of a “phantom limb”: they still experience sensations (sometimes pain) from an amputated body part. This suggests that the brain represents some aspects of body position and sensation as an internal model that does not entirely depend on sensory feedback. Further evidence is provided by a rare disorder called autotopagnosia: despite the patients having intact limbs, brain injury (particularly to the left parietal lobe [Hack #8]) causes a loss of spatial knowledge about the body so severe that they are unable to even point to a body part when asked.
Taken from : Mind Hacks
