split brain research into hemispheric lateralisation

Question 1

explain Hemispheric lateralisation?

Answer 1

-language is subject to hemispheric lateralisation, due to language in most people residing in the left hemisphere

Question 2

explain Sperry’s Split Brain Studies?

Answer 2

• Sperry studied group of people who had undergone operation (commisurotomy) to remove tissue that connects the two hemispheres to control seizures (corpus callosum)
• this removed main communication line between both hemispheres
• allowing him to see how hemispheres were specialised for certain functions

Question 3

Explain Sperry’s procedure?

Answer 3

• projected image of a word visable to pp’s right visual field (processed by left hemisphere)
• same/different image projected in left field
• in normal brain corpus callosum would share info between both hemispheres however in split-brain presenting image to one hemisphere meant that info couldn’t be conveyed from one to another Sperry’s research

Question 4

explain key findings from Sperry’s research?

Answer 4

• SIGHT: when pic of word was in LEFT field split brain reported they could not describe what they saw (reported seeing nothing as language is processed in left hemisphere)
• WORDS: if two words were presented simultaneously on either visual field eg. ‘key’ on left and ‘ring’ on right, pp would select key with left hand and way the word ring (left hand controlled by left visual)

Question 5

explain practical application?

Answer 5

STRENGTH

• Sperry’s work produced many practical findings eg. left hem responsible for verbal tasks
• right performs spatial and muscle tasks
• key understanding of brain process

Question 6

evaluate Sperry’s procedure?

Answer 6

STRENGTH

• standardised procedures
• Sperry’s method of presenting visual data to one hemisphere at a time was pioneering
• he developed a new and improved procedure compared to other researchers who would project image on screen so quick that pp’s wouldn’t be able to allow image to spread across both sides of visual field and brain

Question 7

evaluate issues with Sperry’s procedure?

Answer 7

WEAKNESS
-11 pp’s, small sample, lack of generalisation ability and external validity
-some pp’s had more hemispheric disconnection than others
-control group made up of pp’s with no background of epilepsy
=unreliable, lacks temporal validity