Read Online The New Drawing on the Right Side of the Brain by Betty Edwards - Free Book Online Page A

evidence that each hemisphere, in a sense, perceives its own reality—or perhaps better stated, perceives reality in its own way. The verbal half of the brain—the left half—dominates most of the time in individuals with intact brains as well as in the split-brain patients. Using ingenious procedures, however, the Cal Tech group tested the patients’ separated right hemispheres and found evidence that the right, nonspeaking half of the brain also experiences, responds with feelings, and processes information on its own. In our own brains, with intact corpus callosa, communication between the hemispheres melds or reconciles the two perceptions, thus preserving our sense of being one person, a unified being.
    In addition to studying the right/left separation of inner mental experience created by the surgical procedure, the scientists examined the different ways in which the two hemispheres process information. Evidence accumulated showing that the mode of the left hemisphere is verbal and analytic, while that of the right is nonverbal and global. New evidence found by Jerre Levy in her doctoral studies showed that the mode of processing used by the right brain is rapid, complex, whole-pattern, spatial, and perceptual—processing that is not only different from but comparable in complexity to the left brain’s verbal, analytic mode. Additionally, Levy found indications that the two modes of processing tend to interfere with each other, preventing maximal performance; and she suggested that this may be a rationale for the evolutionary development of asymmetry in the human brain—as a means of keeping the two different modes of processing in two different hemispheres.
    Based on the evidence of the split-brain studies, the view came gradually that both hemispheres use high human-level cognitive modes which, though different, involve thinking, reasoning, and complex mental functioning. Over the past decade, since the first statement in 1968 by Levy and Sperry, scientists have found extensive supporting evidence for this view, not only in brain-injured patients but also in individuals with normal, intact brains.
    A few examples of the specially designed tests devised for use with the split-brain patients might illustrate the separate reality perceived by each hemisphere and the special modes of processing employed. In one test, two different pictures were flashed for an instant on a screen, with a split-brain patient’s eyes fixed on a midpoint so that scanning both images was prevented. Each hemisphere, then, received different pictures. A picture of a spoon on the left side of the screen went to the right brain; a picture of a knife on the right side of the screen went to the verbal left brain, as in Figure 3-4. When questioned, the patient gave different responses. If asked to name what had been flashed on the screen, the confidently articulate left hemisphere caused the patient to say, “knife.” Then the patient was asked to reach behind a curtain with his left hand (right hemisphere) and pick out what had been flashed on the screen. The patient then picked out a spoon from a group of objects that included a spoon and a knife. If the experimenter asked the patient to identify what he held in his hand behind the curtain, the patient might look confused for a moment and then say, “A knife.” The right hemisphere, knowing that the answer was wrong but not having sufficient words to correct the articulate left hemisphere, continued the dialogue by causing the patient to mutely shake his head. At that, the verbal left hemisphere wondered aloud, “Why am I shaking my head?”
    “The data indicate that the mute, minor hemisphere is specialized for Gestalt perception, being primarily a synthesist in dealing with information input. The speaking, major hemisphere, in contrast, seems to operate in a more logical, analytic, computer-like fashion. Its language is inadequate for the rapid complex syntheses achieved by the minor