Biopsychology-Hemispheric Lateralisation

Question 1

What is hemispheric lateralization?

Answer 1

Showing hemispheres of the brain are not the same- they specialise in specific processes

Question 2

What is split-brain research and why is the procedure done?

Answer 2

Research on people who’ve had their brains split in half- severing the corpus callosum; often used as treatment for severe epilepsy

Question 3

What is the Corpus Callosum?

Answer 3

Bundle of nerve fibres that allow communication between the two hemispheres

Question 4

What is the left hemisphere specialized in?

Answer 4

• Language

- Analytical Tasks

Question 5

What is the right hemisphere specialized in?

Answer 5

• Facial recognition
• Music
• Drawing
• Spatial tasks

Question 6

What was a study for hemispheric lateralization?

Answer 6

Sperry and Gazzaniga (1968)

-First to investigate hemispheric lateralisation with the use of split-brain patients

Question 7

What was the method for Sperry and Gazzaniga?

Answer 7

1) -Image/word projected to patient’s LVF/RH or the RVF/LH
2) -When information is presented to one hemisphere in a split-brain patient, the information is not transferred to the other

Question 8

How did the different visual fields respond to the ‘describe what you see’ task?

Answer 8

Picture presented to right visual field (processed by left hemisphere)
-Patient could describe what they saw, demonstrating superiority of left hemisphere when it comes to language production

Picture presented to the left visual field (processed by right hemisphere)
-Patient could not describe what was shown and often reported that there was nothing present

Question 9

How did the different visual fields respond to the drawing task however?

Answer 9

Picture presented to right visual field (processed by left hemisphere)
-While the righthand would attempt to draw a picture, the picture was never as clear as the left hand; suggests RH for visual motor tasks

Picture presented to the left visual field (processed by right hemisphere)
-Left hand would consistently draw clearly and better pictures than the right hand; suggests RH for visual-motor tasks

Question 10

What is the conclusion of this research?

Answer 10

• Key differences between two hemispheres
• LH: Speech and language
• RH: Visual-motor tasks

Question 11

What are the strengths of this research?

Answer 11

• Highlights differences between hemispheres. LH more responsible for verbal and analytical tasks whereas the RH is better at spatial and musical tasks. This has strengthened the understanding of how the brain works
• Use of lab experiments means findings are reliable and replicable. This means that it meets the features of science as it establishes cause and effect. We can therefore assume findings are valid and shows support for the theory of lateralisation

Question 12

What are the weaknesses of this research?

Answer 12

• People who have had the corpus callosum severed due to severe epilepsy are rare > small population > difficult to generalise- the main aim for scientific research is to generate a universal law of behaviour, but with a small sample, this is difficult- therefore, we would accept the theory of lateralisation with caution
• The patients suffered severe epilepsy and were on long term drug treatment, so it may not be valid to compare their brains with ‘normal’ brains