Sperry's Split Brain Research Flashcards
How many symmetrical halves is the brain split into? What are these halves called?
The brain is split into two symmetrical halves. The left and right hemisphere
What is the keyword used to describe how a particular hemisphere may control a specific function?
Hemispheric localisation - when some functions are controlled by a particular hemisphere
What are the two hemisphere connected by?
The two hemispheres are connected by the corpus callosum - a bundle of nerve fibers
What is the function of the corpus callosum?
The function of the corpus callosum is to allow information to be received from one hemisphere to be sent to the other hemisphere
Outline the split brain research:
a. No of patients
b. Purpose of study
c. Procedure
d. Results?
The split brain research used 11 patients known as the split brain patients. The patients were used to study how info from the left visual field goes to the right hemisphere and information from the right visual field goes to the left hemisphere
Sperry blindfolded the patients’ eyes and presented an image to their other eye for a few seconds. This ensured he knew which hemisphere of the brain was being used
Results: Composite words and Matching fsaces
What were the results of composite words?
If two words were presented at the same time, one on either side of the visual field (e.g a key on the left and ring on the right), the patient would write and draw with their left hand the word ‘key’ and say the word ‘ring’. This shows that the right hemisphere is superior in terms of drawing taks. Additionally it would show that speech production is processed by the left hemisphere
What were the results of matching faces?
When participants were asked to match a picture of a face to a series of other faces, the picture processed in the right hemisphere was consistently selected correctly. Whilst the picture on the left was consistently ignored. When a composite picture was shown to each hemisphere, the left hemisphere dominated when they asked to verbally describe it, whereas the right dominated in terms of selecting a matching photo. As a result, Sperry found the right hemisphere specialised in music and spatial skills
What is a strength of the Sperry split brain research? (ethical approach)
Sperry conducted the research in the most ethical way to investigate the isolation of the two hemispheres. The brain being connected by the corpus callosum allows information to be sent to and from both hemispheres.. Practically the way to test this theory would be to find participants with severed corpus callosums or physically severing the bundle of nerve fibers. By using the 11 patients who had undergone commissurotomy Sperry maintained ethical guidelines provided by the BPS
What is the limitation of the Sperry split brain research? (sample size)
Many researchers have urged caution in widespread acceptance, as split brain individuals constitute such an unusual sample of people. There were only 11 participants who took part in all variations of the basic procedure, who all had an epileptic seizures. Therefore it can be argued that unique changes may have occurred in the brain that could have had an influence in the findings. Additionally the control group Sperry used, was made up of 11 people with epilepsy, which may not be generalisable to all.
