split brain research into hemispheric lateralisation

Question 1

hemispheric lateralisation

Answer 1

• idea that hemispheres of brain are functionally different i.e certain mental processes are mainly controlled by one hemisphere e.g language which is localised by brocas and wernickes area + lateralised to left hemp

Question 2

sperrys procedure ( before actual study)

Answer 2

• studied individuals who had undergone commissurotomy.
• involved the corpus callosum, which connects both hemispheres being cut down the middle and separating them
• separation was done to control frequent and severe epileptic seizures.
• Resulted in a lack of communication between the hemispheres.-
• Allowed Sperry to investigate independent functioning of each hemisphere.

Question 3

sperrys procedure ( during actual study)

Answer 3

• developed a procedure to project images or words to patients’ visual fields.
  An image could be shown to the right visual field (left hemisphere) and a different one to the left visual field (right hemisphere).
  In a healthy brain, both hemispheres would communicate about the stimuli.
  After commissurotomy, Sperry’s patients could not achieve this communication.

Question 4

sperrys findings -

Answer 4

image shown to right visual field - p could see what was seen

image shown to left visual field - couldn’t describe what was seen, typically said nothing was there

couldn’t describe what they saw in left visual field bc it was processed by right hemisphere, where there was no language centre to use for speech production
- as a result of comminurotony, messages couldn’t be sent from right hempishere to language centres

• right hemisphere - dominant in recognising faces

-when asked to match face from a series of other faces, picture processed by right hemp, consistency selected
- while faces shown to left hemp =. ignored

Question 5

strength = methodology

Answer 5

p- unqieu method used
e- used specialised and standardised procedures
e- ppts = focused on fixed point , while 1 eye blindfolded , image flashed for tenth of second to either right/eft visual field , preventing eye from moving + ensuring info only reached 1 hemisphere
l- high lvl of control = findings reliable / valid

Question 6

limitation , oversimplified

Answer 6

pp- oversimplified the diff between hemp
e - findings suggest clear split , right = non verbal tasks and left = verbal tasks , but argues that its too simplistic , as both hemp = constantly communicating
e- e.g lashley maze study , learning = involved whole brain , and case JW , damage to left hemp , still able to use right hemp to regain speech , = shows evidence of brain plasticity
l- sperrys work = needed, underestimated brain flexibility

Question 7

limitation , generalisability

Answer 7

p- generalisability
e- split brain patients form small group, procedure rarely done today , sample isn’t representative of population
e- sperrys experimental group = consisted of epileptic patents , control group had no history of epilepsy , mismatch made it difficult to draw accurate comparisons as 2 groups aren’t directly comparable.
l- findings= interpreted with cauton , sample doesn’t relfect population , limits how wide results can be applied