AQA Psychology for A Level Year 2: Rev Guide

If we’re talking hemispheres of the brain, it would seem that opposites attract. Split-brain research into hemispheric lateralisation AO3 Evaluation @ookx hs @ookx hs Daisy had a split-brain operation to treat her severe epilepsy. Most of the time it doesn’t seem to affect her everyday life. But some psychologists have asked her to take part in experiments to test her visual and language abilities. She knows you are studying psychology, so has asked you to explain what she can expect. Use your knowledge of split-brain research to outline what Daisy might expect. 1. Outline research into hemispheric lateralisation. (6 marks) 2. Describe one spilt-brain study. In your answer explain what the researcher(s) did and what they found. (6 marks) 3. Discuss one strength and one limitation of research into hemispheric lateralisation. (3 marks + 3 marks) 4. Describe and evaluate split- brain research. (16 marks) Knowledge Check One strength of split-brain research is it shows lateralised brain functions. The left hemisphere is analytical and verbal (‘the analyser’) and the right is adept at spatial tasks and music (the ‘synthesiser’). The right hemisphere can only produce basic words and phrases but contributes emotional content to language. Recent research suggests this distinction may be too simplified and several tasks associated with one hemisphere can also be carried out by the other. Another strength is the methodology that Sperry used. Sperry’s carefully standardised procedure of presenting visual information to one hemispheric field at a time was quite ingenious. Participants stared at a fixed point with one eye. An image was flashed up for 0.1 seconds, so the patient had no time to move their eyes over the image and spread the information across both sides of the visual field or both sides of the brain. This allowed Sperry to vary aspects of the basic procedure and ensure only one hemisphere received information at a time – a very useful and well-controlled procedure. A further strength is Sperry’s work started a debate about the nature of the brain. Sperry’s work triggered a theoretical and philosophical debate about the nature of consciousness and the degree of communication between the two hemispheres in everyday functioning. Pucetti (1977) suggested the hemispheres are so functionally different they represent a form of duality in the brain (we are effectively two minds). Others argued the two hemispheres are highly integrated and work together in most tasks. The value of Sperry’s work is in prompting this complex debate. One limitation is issues with generalisation in relation to Sperry’s work. Many researchers have said these findings cannot be widely accepted, as split-brain patients are such an unusual sample of people. Only 11 patients took part in all variations and all had a history of seizures. This may have caused unique changes in the brain that influenced the findings. This limits the extent to which the findings can be generalised to normal brains, reducing the validity of the conclusions. A further limitation is differences in hemispheric functions may be overstated. A legacy of Sperry’s work is a growing body of pop-psychological literature that oversimplifies and overstates the difference in function between the two hemispheres. Modern neuroscientists argue these distinctions are not at all clear-cut. Many behaviours that are typically associated with one hemisphere can be performed by the other when situations require. The apparent flexibility of the two hemispheres suggests some of the conclusions drawn by Sperry may be too simplistic. 35