Sperry Flashcards
What were the hemispheres of the brain?
This means the brain was divided into two halves, communicate through a small group of connections and the main connection is called the corpus collosum.
What is hemispheric disconnection?
This involves cutting through the connection between the two hemispheres, the name of this operation is commissurotomy. The two brains would function independently, the problem for functions that are cross wired.
What is the aim?
To record the psychological effects hemispheric disconnection in patients with severe epilepsy. To use the results to understand how the right and left hemispheres work in ‘normal’ individuals.
What were the method designs?
Controlled observation, snapshot study and a quasi experiment.
What are the IVs and DVs?
IV - presence or absence of split brain.
DV - participants performance on the various visual and tactile tasks.
What was the sample?
11 split brain patients who experienced severe epileptic seizures. This was an opportunity sample of participants referred to the white memorial centre in Los Angeles.
What were the materials used?
A tachistoscope - a device that shows an image for a specific amount of time, a back projector. Below the projector screen, there was a gap so that participants could reach objects but couldn’t see them.
What was the basic procedure?
Participants were seated in front of a screen and asked to focus on the middle of the screen, with one eye covered. Images were flashed on the screen for 0.1 seconds. They completed tasks to test how the right and left hemispheres respond to input from the left visual field and the right visual field and the left and right hands.
What was task one?
Recognition of visual stimuli represented to left and right hemisphere separately. A visual stimulus of a picture to the lvf or rvf. Participants were shown same image again to either of the same vf and asked whether they recognised the object.
What was task two?
Responding with speech to visual stimuli presented to the left and right hemisphere separately. A visual stimuli was presented to either the lvf or the rvf. Participants were asked to describe the visual stimulus.
What was task three?
Responding in writing to a visual stimuli presented to the left and right hemisphere separately. Test was identical to second task, except the participants were required to write the name of the stimulus rather than say it.
What was task four?
Pointing to a visual stimuli presented to the left and right hemisphere separately. Test was identical to the second test except the participants were asked to point to the stimulus they had seen.
What was task five?
Recognition of visual stimuli presented to the left and right hemisphere simultaneously. Two figures flashed simultaneously on to the lvf and one to the rvf. Participants were asked to draw with their left hand what they had seen, without looking.
What was task six?
Recognition of pairs related words presented visually and simultaneously to the left and right hemisphere. Words composed of two smaller words were presented to the participants such that half word fell into the lvf and the other into the rvf. Three ways to indicate what they saw: search through objects, write it or say it.
What was task seven?
Verbal identification of objects placed in hands. Participants presented from seeing an object placed in left or right hand. Asked to name the object they had held or retrieve object using either their left or right hand.
