Hemispheric Lateralisation

Question 1

What is hemispheric lateralisation?

Answer 1

the idea that the two halves of the brain are functionally different and that each hemisphere has functional specialisations
e.g. the left is dominant for language, and the right excels at visual motor tasks

Question 2

What is the corpus callosum?

Answer 2

A bundle of nerve fibres that allow information received by one hemisphere to be sent to the other hemisphere

Question 3

What is contralateral organisation?

Answer 3

The fact that each hemisphere controls functioning and information processing from the opposite side of the body

Question 4

Who carried out the first split brain research study?

Answer 4

Sperry and Gazzaniga (1967)

Question 5

What was the aim of the split brain study?

Answer 5

To demonstrate that each hemisphere has a specialised function and ability

Question 6

What was the sample of the split brain study?

Answer 6

11 male, split brain patients
Their corpus callosum had been severed intentionally as a result of severe epilepsy

Question 7

Explain the procedure of the split brain study.

Answer 7

Describe what you see:
A picture was presented to both the left and right visual fields (respectively) and the patient was asked to describe what they saw
Tactile test:
The patient was given an object in their left and right hand (respectively) and were asked to describe what they felt, then pick a similar object from a series of alternate objects
Drawing task:
A picture was presented to both the left and right visual fields (respectively) and the patient was asked to draw the picture with their left and right hand

Question 8

What were the findings of the split brain study?

Answer 8

Describe what you see:
LH - patient could describe what they saw
RH - patient could not describe what they saw

Tactile test:
LH - patient could describe verbally what they felt and pick a similar object from a series of alternate objects
RH - The patient could not describe verbally what they felt, but could pick a similar object from a series of alternate objects

Drawing task:
The right hand would attempt to draw a picture, but the left hand drawing would always be clearer
This happened even though all participants were right handed

Question 9

Ability of multitasking: AO3 ✅

Answer 9

• Rogers et al (2004) found that in domestic chickens, brain lateralisation is associated with ability to multitask (eat food and look for predators)
• Using only one hemisphere means that the other is free to engage in other tasks
• Shows enhancing brain efficiency in cognitive tasks

Question 10

Lacks population validity: AO3 ❌

Answer 10

• Sperry’s research only included 11 participants as cutting the corpus callosum is a rare procedure
• Psychologists have argued that his research is a collection of case studies, so therefore cannot create general laws
• Results cannot be generalised to wider populations

Question 11

Language may not be restricted to the left hemisphere: AO3 ❌

Answer 11

• Turk et al. (2002) discovered patient J.W who suffered damage to the LH
• Despite this, he developed the capacity to speak in the RH
• This led to the ability of speaking about info presented to either side of the brain
• This shows that lateralisation may not be fixed and can adapt following damage to certain areas