HEMISPHERIC LATERALISATION/SPLIT BRAIN RESEARCH

Question 1

Lateralisation

Answer 1

• Lateralisation argues the two hemispheres of the brain have functional differences and specialisations.
• Sperry conducted a quasi experiment on 11 epileptic patients who had undergone corpus callosotomy, that involved cutting the corpus callosum and other tissues that connect the two hemispheres to treat their epilepsy.
• This causes the hemispheres to work independently as they cannot communicate through
  the corpus callosum.
• The brain is cross wired, meaning the right side of the brain controls the left side of the body, vice versa. an image was shown to the patients RVF which was processed by the left hemisphere and vice versa.
• He found that the individual’s were unable to describe objects in the left visual field and this was because of the lack of language centres in the right hemisphere; this demonstrates how language is processed in the left hemisphere.
• Nerve fibres cross over in which all information from the RVF is relayed to the visual cortex in the left hemisphere, and vice versa.
• Which can explain why split brain patients can only ‘see’ images from one visual field as there’s no communication between the hemispheres

Question 2

hemispheric lacterisation

Answer 2

• is the idea that two halfs of the brain are functioning at different times and each hemisphere has different functions

Question 3

what is the left hemisphere dominant for

Answer 3

• language

Question 4

what is the right hemisphere dominant for

Answer 4

• visual motor tasks

Question 5

A limitation of split brain research is that it is not generalisable.

Answer 5

• For example, in Sperry and Gazzaniga’s
  experiment, all 11 participants had a history of epileptic seizures and had their corpus callosum severed,
  where some had other connections intact between left and right hemispheres.
• This is a problem because epilepsy may have affected their brains in different ways, so individual differences don’t allow us to generalise findings on a wider-scale, as well as their brain activity cannot always be generalised to people
  without epilepsy.
• Furthermore, the sample was limited to only 11 people which means there is not a reasonable comparison between epileptic and non- epileptic participants; lacks population validity

Question 6

A strength of split brain research is that it has useful real life applications.

Answer 6

• For instance, conclusions about the functions of hemispheres have been applied to specialist rehab programmes that focus onverbal and visuo-spatial therapy for people who have brain damage.
• This means in understanding
  lateralisation we are able to help those gone through brain damage to accelerate the rate of recovery.
• This is an advantage as it can help improve the quality of life for people and enable them to get back to work at a faster rate; beneficial to the economy- and so great economic implications

Question 7

A strength of split brain research is that it uses scientific methodology.

Answer 7

• For example, due to the unique nature of split brain cases; difficulties in designing a standardised method to investigate split brain patients.
• But, Sperry and Gazzaniga’s method of blindfolding one eye and asking participants to fixate on a dot while an image is flashed for a set time, allowed for an objective and operationalised method that can be replicated.
• Therefore, due to the scientific nature of the methodology, the validity of the findings is increased

Question 8

A limitation of split brain research is that studies often have low ecological validity.

Answer 8

• For example, flashing images of words doesn’t represent how we take in or process information in real life.
• Therefore we are unaware of how people would actually react in real life. In real life there are other factors that
  affect the process of information which were not taken into consideration.
• This is a disadvantage because we cannot accurately apply it to real life and therefore limits the usefulness of research