Lateralisation (Split Brain)

Question 1

Hemisphere lateralisation (split brain)

Answer 1

The right and left have different functions and are connected by the Corpus Callosum, a bundle of fibres that connects the 2 hemispheres and allows fix communication.

Question 2

The right hemisphere

Answer 2

“The synthesiser”, responsible for creativity: facial recognition, social awareness, surroundings awareness, objects and contextual perception - controls the left side of the body.

Question 3

The left hemisphere

Answer 3

“The analyser”, responsible for academics: speech and language analysis, sequencing, recognition of names, words, letters and numbers - controls the right side of the body.

Question 4

Visual fields

Answer 4

In each eye you have a right and left visual field, before going to the applicable hemisphere, everything from the right visual field (in both eyes) is gathered then sent to the left hemisphere for processing (same with the left visual field sent to the right hemisphere for processing first).

Question 5

Speppy- research into lateralisation

Answer 5

• Research on 11 participants that had their corpus colossus cut (for medical reasons).
• Ppts sat in front of a screen and fixated on a dot in the centre .
  A stimuli (picture or word) was presented to EITHER the left or right of that dot.
  If an object was presented to the right visual field, the participant could describe/name it.
  If an object was presented to the left visual field, the ppt could draw it but not say what it is!
• proves that functions are lateralised

Question 6

Speppy AO3, methodology issues/strength:

Answer 6

+ standardised procedures for all participants
- small sample sizes therefore hard to generalise.
- Some had their corpus colossus cut, others had it severed (not fully cut) ⬇️validity.
- Some participants were on drug treatment which impacts “control” = confounding variable.

Question 7

AO3 STRENGTHS

Answer 7

+ Rodger’s: Chickens showed enhanced ability to perform 2 tasks at once (vigilant to predators and looking for food). This suggests lateralisation enhances our brain’s efficiency.

+ Luke: split brain participants are twice as quick at identifying ‘the odd one out’ than normal brain controls. ➡️ suggests the right and left brain are distinct in function and ability.

+ real world application: alien hand syndrome, where the hand functions unconsciously without the person intending to move it. > due to split brain