|Sperry – Hemisphere deconnection and unity in conscious awareness
||Investigate behavioural, psychological and neurological consequences when the left and right hemisphere of the brain is disconnected.
- Subjects were patients who had deconnection surgery to stop epileptic seizure.
- Each hemisphere controls the opposite side of the body.
- They were given a series of tests.
- Test one
- Visual information is presented to the left or right side for 1/10th of a second.
- Eyes will not have time to readjust hence stimulus on the right will be received by the left hemisphere, vise versa.
- Test two
- Present tactile (touch) stimulus to the left or right side.
- Screen is used to cover and remove visual identification.
- Stimulus felt on the left side will be received on the right hemisphere, vise versa.
- Object shown on the left side will only be recognized when its shown on the left side again, vise versa.
- Only objects shown to the right visual field can be named verbally or written down.
- Objects shown to the left visual field cannot be named.
- Subjects were shown a Dollar Sign on the left and a Question Mark on the right.
- They were asked to draw what they see with their left hand (the cannot see their left hand), subjects drew a Dollar Sign.
- When asked what they had just drawn, they would tell the experimenter “A Question Mark”.
- If an object was felt by the left hand, it can only be recognized by the left hand again.
- Brain function is localised.
- Speech and writing comprehension happens in the left hemisphere.
- Processing of image and visuals happen in the right hemisphere.
- There is a different visual perception and memory storage in each hemisphere.
- Made use of patients who underwent hemisphere disconnection surgery as a cure for epileptic seizure, bypassed ethical guidelines of needing to physically harm the subject (even with consent).
- Natural experiment, high in ecological validity.