Either raise your arms or let them dangle by your side. Why the jolt? The answer resides in the right superior and inferior parietal lobules (located above your right ear), where signals from your various senses-visual, somatic-converge to create your internal sense of a body image. The reason for the asymmetry is not clear. You will feel the same kind of jarring sensation, but it will be less powerful than in the preceding case. The left hand appears still but feels like it is moving. Now do the opposite keep the right hand still and move the left hand. The conflict creates a slight jolt it feels spooky, sometimes mildly uncomfortable. The “left hand” in the mirror will appear to move in perfect synchrony with the right but, paradoxically, feel completely still. While continuing to look in the mirror on the right side and keeping your left hand perfectly still, move your right hand, wiggle its fingers or make a fist. (You may need to adjust the position of the left hand to achieve this sensation.) It will now look like you are viewing your own left hand, but of course you are not. If you now look into the right side of the mirror, you will see the right hand’s reflection optically superimposed in the same place where you feel your left hand to be. Now put your left hand on the table at the left side of the mirror (either palm up or down) and match your right-hand position on the right side. Using two bricks, or some duct tape, prop up an 18-inch-square mirror vertically on a table. Would a person who has never looked at his reflection-even in a pool-ever develop a sophisticated self-representation? In doing so, they can reveal a lot about our sense of self.
They can help us explore the way the brain puts together information from different sensory channels such as vision and somatic sensations (touch, muscle and joint sense). But mirrors can reveal a great deal about the brain, with implications for psychology, clinical neurology and even philosophy. YOU PROBABLY LOOK in a mirror every day without thinking about it.