split brain research

Question 1

What is split brain?

Answer 1

• split brain patients have surgery to treat epilepsy
• cut area that connects two hemispheres
• corpus callosum
• major side effect - two hemispheres become functionally separate - act as two independent brains

Question 2

AIM of split brain research

Answer 2

• to investigate the effect of severing connection
• between two hemispheres (corpus callosum)
• on functioning

Question 3

METHOD of split brain research

Answer 3

• natural experiment
  (surgery = natural event)

Question 4

PARTICIPANTS in split brain research

Answer 4

• 11 individuals
• had corpus callosum severed due to surgery

Question 5

PARTICIPANTS of split brain research

Answer 5

• 11 individuals
• had their corpus callosum severed due to surgery

Question 6

PROCEDURE of split brain research

Answer 6

1. • ppt sit in front of a screen
   • fixate gaze on a spot
   • in middle of screen
2. • presented visual information
   • either LVF or RVF
   • for 1/10th of a second
   • not enough time to switch focus to other VF

Question 7

RESULTS of split brain research

Answer 7

• objects seen in RVF named verbally and in writing
• as imaged processed by language centres in LH
• objects seen in LVF only identified through pointing
• not be named as processed in RH no language centres

Question 8

CONCLUSION of split brain research

Answer 8

• two hemispheres have different abilities and functions
• only LH able produce language
• RH can recall and identify information but not verbalise

Question 9

AO3 for split brain research: Strength - scientific methods

Answer 9

P - strength research into HL - uses scientific methods
E - based on objective and empirical techniques - e.g. controlled lab settings
E - which are used to identify which hemisphere responsible for which task - e.g. split brain patients only able say what they saw when image presented to RVF suggests LH activated during language task
L - increases overall internal validity of HL - raising psychology’s scientific status

Question 10

AO3 for split brain research: Limitation - individual differences

Answer 10

P - limitation of split brain research individual differences - relation to how lateralised their brain was
E - degree which corpus callousm severed for each ppt varied greatly
E - some had greater disconnection between two hemispheres than others
L - weakness because research may not be measuring effects of lateralisation effectively - reduces internal validity of split brain research

Question 11

AO3 for split brain research: Limitation - causal relationship

Answer 11

P - weakness of split brain research - causal relationship hard to establish
E - behaviour of Sperry’s split brain ppts compared to neurotypical control group - where no ppts had epilepsy
E - could act as major confounding variable - any differences between two groups could have been due to epilepsy rather than split brain - epilepsy may have caused unique changes in brain that influenced findings of how brain lateralised
L - so difficult to establish whether ppt’s cognitive abilities and lateralisation due to split brain or epilepsy - lowering internal validity of split brain research

Question 12

AO3 for split brain research: RTC by patient EB

Answer 12

P - RTC HL of the brain - case study - patient EB
E - EB suffered brain damage - resulted in removal LH therefore language centres
E - however, after some time regained some language ability - not possible if brain completely lateralised
L - demonstrates language must be in more areas than LH - argue against lateralisation of function and HL