split brain research and hemispheric lateralisation ao3

Question 1

Split brain research weakness

Answer 1

Small sample
Ppt variables - some had drug therapy So not generalised
Task lacks mundane realism and has low external validity

Question 2

Strength - research support

Answer 2

Sperry et al
Pioneering work into the split brain phenomenon had produced impressive and sizeable body of research finsgigs
LH- verbal and analytical tasks
RH - emotional and facial recognition
Rh is synthesiser and LH is analyser
A key contributions to our understanding of brain processes

Question 3

Strength methodology

Answer 3

Sperrys method of presenting visual info to one visual field at a time was quite ingenious typically ppt would be asked to stare at a given point - fixation point
Whilst one eye was blindfolded
The image would be flashed up for 1/10 th of a second meaning that split brain patient wouldn’t have time to move their eye across the image and so and so spread the info across both sides of the visual field
And subsequently both sides often the brain
This allowed Sperry to vary aspects of the basic procedure ans

Question 4

Theoretical basis

Answer 4

Sperrys work prompted a theoretical and philosophical debate about the degree of communication between the 2 hemispheres in everyday functioning and nature of conciuinesse
Some theorists ie pucetti 1977 have suggested that the 2 hemispheres are so functionally different that they represent a form of duality in the brain that in effect we are all 2 minds
In contrast other researchers have argued that far from working in isolation that the 2 hemispheres form a highly inter grated system and both are involved in most everyday tasks
The value in sperrys work is in promoting this complex debate

Question 5

Weakness - issue of generalisation

Answer 5

There were only 11 ppts who took part in all variation of the basic procedure all of whom had a history of epileptic seizures this may have caused unquique changes in the brain that may have influenced findings the drugs taken for this and level of damage is different in each patient before operation so can we even compare results in expirimetl group
Eg some patients had expirenceed more disconnection of the 2 hemispheres as part of their surgical procedure than others
Finally the control group sperry used made up of 11 ppl with no history of epilepsy may have been inappropriate should have compared to other patients with seizures that didn’t undergo procedure of severing the corpus callosum

Question 6

Differences may have been overstated

Answer 6

One perhaps unfortunate legacy of sperrys work is a growing body of pop-psychological
Literature that overemphasised and oversimplified the functional distinction
Although the verbal and non verbal labels can on occasion be usefully applied to summarise the differences the hemispheres modern neuroscientists would contend that actual distinction is less clear cut then this \in the normal brain the 2 hemispheres are in constant communication when performing everyday tasks and many of the behaviours associated with one hemisphere can be effectively performed by the other when the situation requires it
This limits the extent to which findings can be generalised to normal brains reducing the validity of conclusions

Question 7

Further issue w generalsiation

Answer 7

In addition to overestimation in the diffences between both hemispheres there are further issues with generalisation of lateralisation research
Szaflarksi 2006 found that language becomes more lateralised to the left hemisphere with increasing age
But after 25 lateralisation decreased with age
This means that after the brain matures at 25 its harder for the brain to compensate for damage
Therefore this research demonstrates that we cannot generalise findings to all age groups