Explain one study related to localization of function in the brain. (8)

Explain (8) – Detailed account including reasons or causes.

Sperry – Hemisphere deconnection and unity in conscious awareness
[A] 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.