Lesson 7 - Brain lateralisation

Question 1

What is hemispheric lateralisation?

Answer 1

The idea that each hemisphere is different; they each have their own specific function

Question 2

Contralateral

Answer 2

Parts of the left hemisphere deal with the right side of the body and vice versa. If a person has a stroke in the motor cortex of their right hemisphere, the left side will lose motor function

Taste and smell are also contralateral

Question 3

The right hemisphere

Answer 3

It is said to be responsible for emotional recognition in others (Narumoto et al, 2001)

It is also dominant in spatial relationships, meaning spatial recognition. A case study of a woman who had damage to her right hemisphere would often get lost in familiar locations unless she had verbal instructions

Question 4

Corpus callosum

Answer 4

The corpus callosum is a series of connective fibres that join the two hemispheres together. This allows us to process information regardless of what hemisphere it is presented to, because the two halves communicate to each other via the corpus callosum

The fibres can be cut in order to treat patients with severe epilepsy. This allows us to study brain lateralisation, called ‘split-brain research’

Question 5

Strengths of lateralisation

Answer 5

• Studying brain lateralisation helps us understand more about how we multi-task. Rogers et al. (2004) found that in domestic chickens, brain lateralisation helped them simultaneously look for food and remain vigilant for predators . Therefore this is evidence that brain lateralisation enhances dual cognitive function
• Tonnessen et al (1993) found a small but significant relationship between handedness and immune disorders suggesting a link between lateralisation and the development of the immune system. Left handed people may be more prone to allergies and illnesses

Question 6

Weaknesses of lateralisation

Answer 6

• You should be cautious in assuming that brain lateralisation is set in stone for life, as studies have shown that it changes with age. Szaflarski et al (2006) found that language was more lateralised in the left hemisphere up to the age of 25 but decreased after that. It is only relevant up to a certain age - compensation hypothesis
• Lateralisation does not account for plasticity, because if one hemisphere is damaged then the other will take up some of the function