Hemispheric lateralisation

Question 1

what is hemispheric lateralisation?

Answer 1

Hemispheric lateralisation refers to the fact that some mental processes in the brain are mainly specialised to either the left or right hemisphere

Question 2

what does each hemisphere have?

Answer 2

functional specialisations i.e neural mechanisms for some functions such as language which are localised in one half of the brain

Question 3

what has research found?

Answer 3

Research has found that the left hemisphere is dominant for language and speech whereas the right hemisphere specialises in visual-motor tasks

Question 4

how do these two hemispheres communicate?

Answer 4

through the corpus callosum which enables the hemispheres to be connected

Question 5

Name research that supports hemispheric lateralisation

Answer 5

Szaflarski et al., (2002) used functional magnetic resonance imaging (fMRI) on individuals who were left hand dominant, whilst they completed language acquisition and non-linguistic tasks.
It was found through the fMRI that there was more activation in the right hemisphere of the participants, concluding that they had typical language dominance.

Question 6

Name an evaluation point

Answer 6

• it is related to neural capacity
• by using one hemisphere to engage in a particular task (language/mathematical ability) this would leave the other hemisphere free to function
• however despite this assumption, there is little empirical evidence that suggests that lateralisation confers any advantage to the functioning of the brain in humans.
  Except for research conducted by Rogers et al 2004 who found that in the domestic chicken, brain lateralisation is associated with enhanced ability to perform two tasks simultaneously

Question 7

Name a second evaluation point

Answer 7

There are disadvantages associated with hemispheric lateralisation
such as the fact that it may lead to poor immune system functioning
architects and arithmeticians tend to have superior right-hemispheric skills but are also likely to be left handed and suffer from high rates of allergies and problems associated with poor immune abilities
Tonnessen et al 1993 found a small but significant relationship between handedness and immune system disorders, suggesting that the same genetic processes that led to lateralisation may affect the development of the immune system

Question 8

Name a final evaluation point

Answer 8

Lateralisation changes with age
For example, research has found that lateralised patterns associated with younger children develops into bilateral patterns in healthy adults.
Szaflarski et al in 2006 found that language became more lateralised to the left hemisphere with increasing age in children and teenagers but after the age of 25, lateralisation decreased with each decade of life