Bio Psych: Sperry Flashcards
(16 cards)
What was the aim of sperry’s study?
To investigate the effects of hemispheric deconnection on perception and memory
What is a commisurotomy?
The division of the two hemispheres via surgery
What is the lateralisation of function?
Hemispheres of the brain have different and specific functions
Why did Sperry conduct the study?
He set out to use split brain patients to show that each hemisphere possess its own stream of conscious awareness and has its own separate chain on memories the other doesn’t have access too
What was Sperry’s sample?
- 11 split brain patients, all had their corpus collusion severed
-opportunity sampling
-repeated measures design
What methodology did Sperry use?
- quasi experiment
-qualitative data
-involved comparing the participants performance to people who didn’t have a split brain
-IV= where participants had their hemispheres disconnected
-DV=performance of the various tasks
Summary of task 1
-sending visual information to one hemisphere then asking the ppt to name it
-ppt will have a blind fold over one eye then asked to fixate on the black dot in the centre of the screen
-visual stimulus will be shown on the right or the left on the screen for 0.1 seconds
-language is processed in the left hemisphere, so when a stimulus is presented to the LVF the split brain ppt shouldn’t be able to name it
Summary of task 2
-sending tactile information to one hemisphere then asking the ppts to name it
-ppts will have a stimulus placed in one of their hands while still unable to see and asked to name it
-as this is dealt with the left hemisphere, when a stimulus is presented to their left hand the split brain ppts should not be able to name it
Results of task 1
-when an object was presented to a visual field one after another the ppt only recalled seeing it once
-if a stimulus was presented to the RVF for a second time they responded as if they had seen it before
-they were not able to give a description of the stimulus if presented to the LVF as it went unnoticed, however those who were right handed were able to match the stimulus with their left hand
-if two symbols were presented they would draw what they saw in the LVF with their left hand, the would name the stimulus presented to the RVF
Results of task 2
-objects put in the ppts right hand for identification could be described both verbally or written down, when in left hand they would either guess or the object would go unnoticed
-if an object was in their left hand and placed in a grab bag they would recognise and retrieve the object with the same hand
-if two objects were placed in both hands then placed in two separate grab bags, the ppts were able to find the object with the hand it was placed in
Strengths of Sperry’s study
-looks at the brain, unable to show demand characteristics
-quasi experiment, high in ecological validity
-qualitative data, rich in detail
Weaknesses of Sperry’s study
-small sample, can’t be generalised
-would be more valid to compare the split brain people to people who have suffered with severe epilepsy
-quasi experiment, no control over the IV
Is Sperry’s study reliable?
-yes, highly standardised, lab environment
-easily replicable, all do the same tasks
Is Sperry’s study valid?
-yes, non-tested eye was covered with an eye patch and were unable to see their hands in the tactile test
-however, comparison group could have been people with epilepsy like the ppts had
Is sperry’s study ethnocentric?
-no, it may only be generalisable to English speakers, differences in lateralisation of function in different cultures eg: bilingualism
What was the usefulness of of sperry’s study?
-found that the hemispheres do have different functions, can help with therapies
