The Relationship Between Handedness and Hemispheric Dominance PDF

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An investigation working on laterality...

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The Relationship Between Handedness and Hemispheric Dominance Abstract: In this study, the correlation between handedness and hemispheric dominance was investigated. It was hypothesised that year 11 students who do psychology and use and prefer their right hand as measured by completion of a survey, will use the left hemisphere of their brain more than those who prefer their left or are ambidextrous which was assessed based on a response of a video presented. 17 year 11 students were conveniently sampled and given a survey to complete. Results were collated and found a weak negative correlation between handedness and hemispheric dominance, indicating that people who preferred their right hand had a more dominant left hemisphere. The hypothesis was supported but could not be generalised to all year 11’s due to convenient sampling rendering the results unrepresentative of the whole population. Introduction: Handedness is described as the tendency to use one hand over another. This is associated with whether someone is right-handed, left-handed or ambidextrous (uses both hands equally), (Laterality, 2019). Hemispheric dominance is a theory which proposes that the two hemispheres of the brain specialise in different types of thinking, (Cherry, 2018). Past research by Paul Broca in the 1800’s, demonstrated that when he localised a section in the left frontal lobe, and that section became damaged, a person’s reading, writing and speaking ability would decrease. This area is known as Broca’s Area, (Laterality, 2019). More recently, Sperry and Gazzaniga were researching effects of epilepsy. They found that cutting the corpus callosum in half will reduce or eliminate epileptic seizures. The corpus callosum is a band of fibres connecting the two hemispheres of the brain allowing them to communicate with one another. So, when their patients were unable to name objects that were registered by the right hemisphere but able to name the object when processed by the left hemisphere, they concluded that language was controlled by the left hemisphere. The aim of the investigation was to determine the relationship between handedness (hand preference and strength) and hemispheric dominance of the brain. It was hypothesised that year 11 students who do psychology who use and prefer their right hand as measured by completion of a survey, will use the left hemisphere of their brain more than those who prefer their left or are ambidextrous which was assessed based on a response of a video presented. The two behavioural variables were the hemispheric dominance of participants (whether they were left or right-brained) and the handedness of participants (whether they were left handed, right handed or ambidextrous) Methodology: Participants: Seventeen year 11 psychology students from Kennedy were used in the study. Ages ranged between 15 and 18, with a split of 7 males and 10 females. Materials: The following materials were used to conduct the study - A list of numbers between 1 and 17 to use as student identification - 17 pens - 17 video response and handedness questionnaire sheets (appendix A) - Hemispheric dominance video - 17 handedness and hemispheric dominance score sheets (appendix B) - 1 data sheet to record scores (appendix C)

Procedure: Participants were selected from the Year 11 psychology class using convenient sampling and randomly given a participant number. Participants then filled out the handedness questionnaire followed by watching a video and filling out their responses on the sheet. The participants were then given their score sheet to calculate their handedness and hemispheric dominance scores, their gender and participant number was to be written on the top and given in. The results were then collated and used to compare handedness with hemispheric dominance Results:

The Relationship Between Handedness and Hemispheric Dominance 18

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Handedness Score

The points have a general trend along a negative line, this indicates that the two behavioural variables have a weak negative correlation and go in the opposite direction, this means people who were right handed were generally more left brained.

Discussion: It was hypothesised that year 11 students that do psychology who use and prefer their right hand as measured by completion of a survey, will use the left hemisphere of their brain more than those who prefer their left or are ambidextrous which was assessed based on a response of a video presented. The two behavioural variables are the hemispheric dominance of participants (whether they were left or right-brained) and the handedness of participants (whether they were left handed, right handed or ambidextrous). The hypothesis was accepted in that the results showed a weak negative correlation between handedness and hemispheric dominance, which means that people who preferred their right hand had a more dominant left hemisphere. An extraneous variable that could have affected the results include lying. Because this was self-report questionnaire, people could have lied to achieve the results they wanted, this could have given the results bias. One way to overcome this is to have a spoken survey and to give the participant 2 seconds to reply, this would mean that the first thought to come to their brain would be given rather than the informed thought. Another extraneous variable could be sample size, a larger sample size would be beneficial to the investigation as it would be more representative of the population, unfortunately we only had the Year 11 psychology class to test, this resulted in convenient sampling which introduces bias to the study. This could be avoided by opening the investigation up to the all the year 11s in the school and using random sampling to eliminate bias. Conclusion: It can be concluded that year 11 students that do psychology who use and prefer their right hand as measured by completion of a survey, will use the left hemisphere of their brain more than those who prefer their left or are ambidextrous which was assessed based on a response of a video presented. These results are unable to be generalised to all year 11 students who do psychology as only one class was used. References: Cherry, K. (2019, 3 16). Left Brain vs Right Brain Dominance: The Surprising Truth. Retrieved from verywellmind: https://www.verywellmind.com/left-brain-vs-right-brain2795005 laterality. (2019). laterality. Retrieved from Britannica school: https://school.eb.com.au/? target=%2Flevels%2Fhigh%2Farticle%2Flaterality%2F47279...