Lateralisation of Function*

Question 1

Name the area of the brain that connects the two hemispheres.

Answer 1

Corpus Collosum.

Question 2

Define contralateral control.

Answer 2

The idea that the left hemisphere controls the right of the body and vice versa.

Question 3

What did Sperry and Gazzaniga study?

Answer 3

Sperry and Gazzaniga studied patients with a severed corpus collosum. Either from surgery or injury.

Question 4

What did Sperry and Gazzaniga find?

Answer 4

Describe what you see:

• Right visual field - able to describe
• Left visual field - unable to identify any image

Tactile test:

• Placed in right hand - able to describe what they felt
• Placed in left hand - could only make wild guesses.

Drawing tasks:

• Right visual field - drawings were clearer with the left hand
• Left visual field - drawings were clearer with the left hand.

Question 5

What can be concluded from Sperry and Gazzaniga’s findings?

Answer 5

• The left hemisphere is dominant for speech and language.
• The right is dominant regarding visual-motor tasks.
• The two hemispheres are specialised.

Question 6

Give an advantage of lateralisation of function.

Answer 6

• Supporting evidence from Rogers et al - evolutionary advantages for chickens with separate hemispheres - animal study - difficulty extrapolating.
• High practical validity - Sperry’s findings demonstrate the impact of treatment for epilepsy useful for weighing the risks and benefits of treatment.

Question 7

Give a disadvantage of lateralisation of function.

Answer 7

• Findings question the principle of lateralisation - Szaflarki et al. - lateralisation becomes more profound with age - increased lateralisation to the left in terms of language - becomes less lateralised with age - samples in studies must be mindful of this change.
• Language may not be restricted to the left hemisphere - Turk et al - JW suffered damage to the left though developed an ability to speak using the right hemisphere - challenges the accuracy of this theory.