Hemispheric lateralisation and split-brain research

Question 1

What is brain lateralisation?

Answer 1

-The way different hemispheres of the brain have different functions
-e.g. Right hemisphere controls left side of the body and vice versa

Question 2

What is hemispheric lateralisation?

Answer 2

-The idea that the two halves of the brain are functionally different
-certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other.

Question 3

What is contralateralisation?

Answer 3

• it is when the RH is responsible for the left side of the body and vice versa
  -e.g this happens in the motor area- right side controlled by LH
  -vision is contralateralised and ipsilateral (opposite and same-sided)

Question 4

Explain how vision is contralateralised and ipsilateral?

Answer 4

• The RVF of both eyes are connected to LH , and LVF of both eyes are connected to RH

Question 5

Evaluation of hemispheric lateralisation

Answer 5

-S: Research support for lateralisation connected brains: Gereon Fink et al. (1996) used PET scans and showed when people were looking at wider details of pictures RH was more active and LH more active in finer details
-L: One brain: idea that RH is synthesiser and LH is analyser may be wrong as the idea that people have a dominant side of the brain which creates a different personality. Jared Nielsen (2013) analysed brain scans from over 1000 people aged 7-29 and found people use different hemispheres for different tasks but there was no evidence of a dominant hemisphere- no artists brain or mathematics brain

Question 6

Describe the procedure of Roger sperry’s (1968) research into split-brain?

Answer 6

-11 people who had a split brain( because of removing corpus callosum to reduce epilepsy)
-they were studied in a set up where images could be projected to LVF (RH) and the same or different image projected to RVF (LH)
-In a “normal brain” the corpus callosum would instantly communicate what it saw but this is not applicable in split-brain people

Question 7

Describe the findings of Roger Sperry’s (1968) research into split-brain?

Answer 7

-If an image was shown to RVF the person could describe what they see but if it was shown to the LVF they said ‘there was nothing there’
- while the person could not describe it they were able to select a similar object using their left hand (RH) and would produce a emotional response to images (e.g. giggling)

Question 8

What are the conclusions of Roger Sperry’s research?

Answer 8

-shows how some brain functions are lateralised
-LH is verbal
-RH is silent but is emotional

Question 9

What is the evaluation of split-brain research

Answer 9

-S: Research support: Michael Gazzaniga (luck et al. 1989)found that split-brain participants perform better than normal brain people in tasks such as identifying the odd one out in an array of similar objects. Kingstone et al . (1995) the LH’s cognitve abilities are watered down by RH
-L: Generalisable issues: None of the control group of neurotypical people had epilepsy which is a massive confounding variable as the differences between the 2 groups could have been because of epilepsy.