Biopsychology- Hemispheric Lateralisation

Question 1

Hemispheric lateralisation

Answer 1

Idea that two halves of brain are functionally different and each hemisphere has functional specialisations

Question 2

Functions within the brain are generally Contralateral- meaning?

Answer 2

Side of brain opposite side of body a condition occurs

• evolutionary strengths

Question 3

What happens if corpus callosum was cut? (Corpus callosum- facilitates inter-hemispheric communication)

Answer 3

Right and left side will not be able to communicate to each other

• can cut if children have severe seizures

Question 4

Split brain A01

Answer 4

Sperry and Gazzangia (1967)- all ppts right handed
Aim: examine extent to which two hemispheres are specialised for certain functions

Method: studied 11 individuals who had commissurotomy- control group 11 people no epilepsy and corpus callosum intact. Image projected to patients left vidual field or right. When info presented to one hemisphere in split brain patients, info not transferred

Procedure- many different experiments- describe what see (picture shown to left or right and describe what see)
Tactile test- object placed in hand and describe what felt or choose object from other objects
Drawing task- picture in left or right and had to draw it

Findings: seeing task- object in left visual field unable to describe
Object in right visual field able to describe
Language in left hemisphere

Drawing task- in left visual field (right hemisphere) can draw
In right vidual field (left hemisphere) can’t draw
Motor tasks in right hemisphere

Question 5

Conclusions of sperry and gazzaniga

Answer 5

Highlights- Number of differences
between two hemisphere

Left hemisphere dominant language
Right hemisphere dominant visual-motor task

Question 6

Evolutionary advantage hemispheric lateralisation

Answer 6

Allows for cognitive multi-tasking which would increase chances of survival

Question 7

Generalisability (Ao3)

Answer 7

Low in generalisability/ population validity
Bc very specific patients- epilepsy- small numbers
Make broad statements about having a split brain making assumptions about functions of split brain from a clinical population
Conclusions only representative of individual with epilepsy

Idiographic approach

Question 8

Scientific nature of research Ao3

Answer 8

Split brain scientifically credible
Highly controlled study- small cohort- carefully documented process, becomes a paradigm
Can test reliability of findings
So increase reliability of findings

Question 9

Lack of controls A03- counter argument

Answer 9

Research can be criticised for lack of controls
Comprised of no epilepsy and no cut CC
Not valid comparison because don’t know if bc of epilepsy or bc of the cut
Cannot establish cause and effect

Question 10

Contradictory research findings (JW)

Answer 10

Case study of JW
Suffered damage to left hemisphere but developed ability to speak using right hemisphere- could speak about info (from fields) sent to either side of brain
Contradicts- shows brain can learn to adapt and compensate- adapting and changing all time
Shows neuroplasticity- become less lateralised as we age

Question 11

Contradictory research from Kim Peek

Answer 11

Case study Kim peek

Born without corpus callosum- large ability to recall books word for word and read 2 pages in 10 seconds

Language normally processed in temporal lobe and involves contralateral transfer to process what’s read- but peek reads 1 page with left eye and 1 page with right so is separate and still works

Has bilateral language centres- shows plasticity of brain and can adapt