John Vlahos
Professor Bob Melara
Psychology 102
31 October 2016

Using the Correlation Method to Study the Divided Brain
The purpose of this paper is to evaluate the correlational method as a means for examining the relationship between functions of the left and right hemispheres. I will compare the performance of people with intact brains with the performance of so-called split-brain patients. In many ways, the brains of these two groups are very similar. 1a. The brainstem is located at the innermost center of the brain and is connected directly with spinal cord. The functions of the brainstem are alertness, arousal to stimuli, breathing, controlling the blood pressure, controlling the heart rate, regulating digestion, and controlling other autonomic functions. There are not any differences in the functions of a normal brainstem and a split-brain brainstem. 1b. The hippocampus is located in the medial temporal lobe, near the center of the brain. The main function of the hippocampus is to store long-lasting memories, such as events or facts. No differences are observed in the anatomy of hippocampus between a person with a normal brain and a person with a split-brain. 1c. The corpus callosum is a group of neural fibers that connect the two hemispheres of the brain and share the neural messages of the hemispheres to one another. The anatomical differences of the corpus callosum of a normal brain person and a split-brain person is that the split-brain person has his corpus callosum severed through surgery. 1d. The cerebral cortex is located at the top of the cerebrum. The cerebral cortex is the place that information processing takes place and complex thinking and perception. People with a split-brain still retain the functions of their cerebral cortex, but because their corpus callosum is severed the neural messages of one hemisphere are not passed to the other hemisphere therefore they have localized functions on their cerebral cortex.

The split brain patient provides scientists with a window into the normal functions of the brain. 2a. The split-brain patients originally suffered from epilepsy. Epilepsy caused high brain activity that resulted in seizures. The surgical technique to treat epileptic seizures is to cut the corpus callosum. 2b. In order for psychologists to learn in which hemisphere language perception occurs, split-brain patients have taken a test where they had to look at a screen with a dot in the center. On the left of the dot was the word "HE". On the right side was the word "ART". The image "HE*ART" flashes for an instant in the screen. When asked what word did they see the say the saw the word "ART". But when asked to show what word they saw they used their left arm to pinpoint the word "HE". Therefore, because objects in the right visual field are processed in the left hemisphere language perception must be a function of the left hemisphere. 2c. The results of the split-brain patient studies gave a new insight on the lateralization of the brain in the general population. It is now known that the normal brain show laterality in its functions even though the carpus callosum is intact. Further studies showed that the normal brain hemispheres perform the same function as split brain hemispheres.
Cognitive tests performed on split-brain patients have identified a division of labor between hemispheres. It is conceivable that functions handled by the different hemispheres will show a strong relationship in the general population, but not in split-brain patients. 3a. The functions that are specialized in the left hemisphere are the functions of thought and logic, the ability to recognize and imagine details, performing computations, and understanding language. The functions that are specialized in the right hemisphere are the functions of perception, the ability to understand groups of objects, making connections and deductions, and emotions and creativity. 3b. Split-brain patients and intact brain persons can be tested in order to determine the lateralization of the hemispheres in the human brain, using the Correlation Method. 3c. After the tests have been performed and the results noted, the Correlation Method will be used to help determine if split-brain patients and intact brain people have substantial similarities in brain laterality.
Data were collected from a group of split-brain patients and