Hampson (1996) developed a study involving the divided visual field paradigm and a phonological rhyme/non-rhyme task to test the speed and accurateness of either side of the brain. This study was used to investigate functional asymmetry between the left and right hemispheres in phonological processing. The research was taken out equally on 15 male and 15 females London Metropolitan University students ranging from ages 18 – 35 years old.
They were all specifically chosen to be right–handed and had English as their first language thus providing a fair experiment to see whether our left hemisphere (left side of the brain) or the right hemisphere is faster and more accurate. In conclusion using the mean and standard deviation to determine our hypothesis, it was calculated that the left hemisphere had a higher mean and standard deviation score compared to the right hemisphere. Introduction
The cerebral hemispheres are very similar in appearance, but they differ significantly in their structure. One of the best known differences between the two structures is motor control; the right hemisphere controls the left half of the body and the left hemisphere controls the right side of the body. These motor control differences were discovered mainly through the examination of paralysis caused by strokes or other damage to a specific hemisphere. Even though the two hemispheres have different functions, they do not work independently of each other.
They communicate back and forth across the corpus callosum. This is not an equal partnership however; one hemisphere usually dominates over the other, an effect best illustrated by the fact that most people are only good with either their right or left hand. In most cases the left hemisphere is believed to be the dominate hemisphere. Since 1836, there has been a lot of research and studies on whether the brain is symmetrical or not. Over the years there has been very debatable discussions based on this study.
There are five methods of studying cerebral lateralization of function: unilateral lesions, the sodium amytal test, the dichotic listening test, functional rain imaging and studies of split brain patients. In acknowledging the stated above we replicated a study developed by mead & Hampson (1996) involving the divided visual field paradigm and a phonological rhyme/non-rhyme task to test the speed and accurateness of either side of the brain. The results of this study show us the brain is not in fact symmetrical and the two hemispheres in the brain work in different ways.
The left hemisphere is known to play the dominant role, which is in control of all complex behavioural and cognitive processes as for the right hemisphere it only plays a minor role. This report will further analyse how different the two hemisphers is the dominant side of the brain. Method Participants There were a total of 30 participants insisting of 15 females and 15 males who are currently student of LMU, with an age range of 18 – 35 giving the mean age of 22. 8.
All participants were specifically chosen to be right- handed with English as their first language. It was also vital that the participants had normal or corrected to vision. Each participant was provided with a consent form for his or her acknowledgment of the experiment and was treated in accordance with the ethical principles of the BPS. Apparatus The equipment used consisted of a 60 Hz monitor on a 19 – inch computer screen. The program for the test ran on a viglen Pentium 4. 30 GHZ.
To present the stimuli’s four types of word pairs were used; ‘Look similar and rhyme’, ‘look similar and do not rhyme’, look dissimilar and do not rhyme. ’ look dissimilar and rhyme. ’ Procedure The participants had a limited amount of time to decide if the cue and targets words that were shown together rhymed or not, if the two words rhymed the participants were expected to press the ‘k’ key and if the two didn’t rhyme they were expected to press the ‘a’ key. The participants were told to sit at a distance of 30 cm from the computer screen.
Before the test began a set of instructions were presented to each participant explaining the test will begin with a set of 20 practice trials (10 rhyming and 10 non-rhyming words), which is then followed by two blocks of 40 experimental trials (40 rhyming and 40 non-rhyming words). The words shown were a mixture of verbs and nouns. After being told to locate and double click the ‘cereb’ icon on the computer desktop. They were told to focus on the central fixation point (+) that appeared for one second, followed by the cue word for one second, the screen would then go blank for 20ms and the target and distracter was displayed for 200ms.
The trials were equally halved of left and right visual field presentation, which were given in random orders for each participant. Results In conclusion, the consequences of the study sided with our hypothesis; “The left hemisphere is faster and more accurate than the right hemisphere. ” Discussion The 30 participants would have a higher score on the left hemisphere than on the right was what our hypothesis had predicted. The results showed that it was indeed the case as they scored an average of 68. 07 on the left and an average of 63. on the right. According to the critical value for the Wilcoxon signed test, the T value is equal to 147. 5. Since our hypothesis is supported, we can reject the null hypothesis that signifies that there is no brain lateralization. On the critical value for the Wilcoxon signed rank test table we looked at the ‘n=30’ considering we had 30 participants in our study, therefore knowing that we have a one-tailed hypothesis and that the T value is equal to 147. 5, the corresponding critical value on the table is 151.
This contemplates that our hypothesis is supported because the left hemisphere appeared to be more accurate in a rhyme/non-rhyming task. While the results support the hypothesis, it would be interesting to have a bigger sample of people. The participants in this study were between 18 and 35 years old, a broader analysis could be done if older and younger participants are also chosen to participate in the study in addition to help us determine whether or not age is a factor to consider in regards of the capability of the hemisphere in performing certain tasks
