Localisation of Function

• A strength of localisation of theory is that there is brain scan evidence to support it.
• For example, Peterson used brain scans to demonstrate how Wernicke's area was active during a listening task, and how Broca's area was active during a reading task.
• This suggests that these areas of the brain have different functions; Wernicke's area is used for language comprehension and Broca's for language production.
• This strengthens both the internal validity and support for research into localisation of function in the brain as there now exists a number of sophisticated and objective methods for measuring activity in the brain.
• Another strength is that unique cases of neurological damage support localisation theory.
• For example, Phineas Gage who received serious brain damage in an accident in which he survived. However, damage to his brain affected his personality.
• He went from someone who was calm and reserved to someone quick-tempered, rude and 'no longer Gage'.
• This strengthens both the validity and support for research into localisation of function in the brain given that Gage's change in temperament following the accident suggests the frontal lobe is not only responsible for motor functions, but also regulating mood.
• A limitation of localisation theory is that it uses a unique case study.
• For example, the nature of the Phineas Gage case study is unique and idiographic.
• This makes it difficult to re-test and see if the findings can be replicated.
• This therefore weakens both the population validity and support for research into localisation of function in the brain as we are unable to generalise the findings of this study to explain human behaviour for all.