One Brain or Two?
Numerous researches and experiments have been done based on whether the human being possess one brain divided into two parts (left and right hemisphere) or whether we have two different brains working together. The psychologist Roger W. Sperry was the first on research this topic with some experiments on animals. Then, he later started working with Michael Gazzaniga. They were able to find split-brain patients. Those patients had their brain split as way of reducing or stopping uncontrollable epilepsy. Many agreed to participate in the experiments. The experiments that they held focused on finding out what kind of limitations would each brain have if they operated independently, how the 5 senses would be affected as well as finding their unique abilities. The two hemispheres were analyzed with three different tests. One of the tests studied their visual abilities and interpretations. The test consisted on placing an image at a specific place while having their eyes fixed at a determined point. So that would make the patient capture the visual information in only one of the visual fields (area) of the right or left hemisphere. Interesting findings came out of this test. The patients claimed verbally to not have seen anything on the right field. However, when they were asked to point at the image seen, they pointed at the image on the right field where they had claimed to not have seen anything. These results lead Sperry and Gazzaniga to a logical conclusion: Our speech is controlled by the left hemisphere only. In other words, split-brain patients were not able to verbally express or even confirm what the right hemisphere has seen. Another of Gazzaniga and Sperry tests focused on tactile stimulation. This test was really simple. It consisted on being able to touch different items without seeing or hearing it. The results of this experiment give to the previous Gazzaniga and Sperry logical conclusion more...
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