Split Brain Research Flashcards
Define hemispheric lateralisation
Refers to the idea that some mental processes in the brain are mainly specialised to either the left or right hemisphere
Describe main functions associated with the left hemisphere
Language, logic, analytical thought
Describe main functions associated with the right hemisphere
Holistic thought, creativity, intuition
What connects the two hemispheres?
Corpus callosum —> bundle of nerve fibres connecting two halves of the brain
What are the left and right visual fields?
Everything seen from the left side until the nose, and vice versa (processed by opposite hemisphere)
Describe split brain experiment
Sperry 1968
- quasi experiment - 11 ppts, had severe epilepsy and corpus callosum had been split
- ppts gazed at fixation point on a screen
- slides were projected on either side of fixation point (L or R visual field) for 1/10 of a second
- found functions each hemisphere is linked to
Give strengths for split brain research
+ demonstrated lateralised brain function —> research shows left hemisphere = analytical/verbal tasks whilst right = spatial tasks
Sperry:
+ no ethical issues as corpus callosum already severed
+ standardised - can be replicated, high reliability
+ fast presentation at a 1/10 of a second isolates the visual fields, high IV
Give limitations of split brain research
Lack of ecological validity as patients in reality are able to adjust their visual fields, may tell us little
Population validity —> very small sample, not large enough to generalise; also all had severe epilepsy which may alter brain structure, should be compared to others with epilepsy
Individual differences —> Szaflarski found language became less lateralised to L hemisphere after 25, suggests aging affects lateralisation so only generalisable to YAs
confounding research —> patient JW developed capacity to speak from RH, can now speak about info presented to either hemisphere; suggests effect of lateralisation is overstated and not as clear cut as previously thought
