Sperry (1968) Hemisphere Deconnection And Unity In Conscious Awareness Flashcards
What is the name of the bundle of fibres which connects the two hemispheres of the Brain?
Corpus callosum
What is the Corpus Callosum’ primary function?
The structure allows the two hemispheres to communicate with each other. information that is processed in one hemisphere passes through the Corpus Callosum into the other hemisphere.
Why might someone undergo a commisurotomy
If they have severe epilepsy- if the hemispheres were separated the seizures could be contained in one half of the brain. Therefore causing less damage to the person.
What information does the left hemisphere of the brain process?
- Language
- Maths
- Info from right visual field
What information does the right hemisphere of the brain process?
- Pictures/Symbols
- Emotion
- Info from the left visual field
What is the aim of the study?
To study the effects of hemisphere de-connection and to show each hemisphere has different functions. (Lateralisation of functions).
Describe Sperry’s Sample
> 11 split-brain patients with a history of advanced epilepsy that couldn’t be controlled with medication
First patient (male) had surgery over 5 and a half years before the study.
Second patient (female) had surgery over 4 years before the study.
The other 9 patients had surgery at varying times but not long before the study
RESEARCH METHOD
1) what type of experimental method was used?
2) what are the IV and DV
3) why can this study also be considered to be a case study?
1) Quasi-experiment
2) IV= split-brain participant or not
DV= performance on various tasks (that used one hemisphere)
3) This piece of research studied a small group of participants in depth.
How did Sperry ensure visual information only reached one hemisphere of the participants brains in the visual task?
Images flashed on a 35mm transparency from the standardised projector for 1/10th of a second to either the left or right visual field whilst the other eye was covered with an eye patch.
Why was visual information only presented for 1/10th of a second in the visual task?
To ensure that participants didn’t have time to move their eyes as if information was presented to both fields it would be presented to both hemispheres.
Sperry was also interested in how the brain processes tactile information. How did he test this in the tactile tasks?
Below the screen there was a gap so they could reach objects but not see their hands. Objects were placed in the left or right hands or both. Information about the objects in the left hand were processed in the right hemisphere and vice versa.
HYPOTHESIS
1) what would happen if visual information is presented to the left visual field?
2) what would happen if tactile information is processed by the left hand?
1) you would not be able to verbalise the information but could draw it with your left hand
2) you would not be able to verbalise it but you would be able to select the object with your left hand.
In what task did the split brain participants perform better than ‘normal’ participants? And why?
When searching for 2 objects in a tactile task. This was because each hand worked independently as information is not communicated between hemispheres but stored solely in its processed hemisphere, therefore the corresponding hands would locate their own object independently.
Did the split Braun operation have any impact in the participants intelligence?
No
What effects did the split brain operation seem to have?
Short term memory, orientation and concentration.
