Psychology Case Studies

One Brain or Two? There are two halves to the human brain, called hemispheres. The left side of the brain controls the right side of your body, and the right side controls the left side of your body. The left side of the brain also has the control of the ability to speak and communicate using language. The right side has more artistic abilities, such as spatial relationships. Some people believe that the halves may be two completely different mental systems. The two halves of the brain are connected by the corpus callosum; a structure of about two hundred million nerve fibers called. If the corpus callosum is cut then the two halves of the brain have no way of communication, and must operate independently. The first psychologist researching this idea was Roger Sperry. He made many discoveries using animals as the subjects. Researchers developed three different types of tests to study how the brain works when separated. One of the tests examines visual abilities. Another test was designed for tactile stimulation or touch. The third test was used to test your auditory abilities, or hearing.
These various forms of tests were performed on patients after performing surgery of clipping the corpus callsumi. The patients’ intelligence and emotions seemed the same, however when testing began they showed unusual behavior. One of the tests for the visual abilities was to have the patient sit in front of a row of lights. They were asked to look at the center light while the lights flashed on both sides. The patients said they only saw the right side light up. Then when the scientists had them take the test again, and this time asked them to point to the side at which the lights were flashing. The patient responded with pointing at both. This test helped to discover the center for speech is in the left hemisphere of the brain. The information of the flashing lights was sent to both sides of the brain from the eyes. Because the patients first said they only saw the right