Biopsychology - Localisation of function in the brain Flashcards
What is the cerebral cortex?
The cerebral cortex is the 3mm thick covering of the brain, and is much more developed in humans than in other animals.
What are the 4 lobes and what areas do they contain?
Frontal lobe - motor area
Parietal lobe - sensory area
Occipital lobe - visual area
Temporal lobe - auditory area
Damage to any of these areas will result in reduced specific functioning. For example, damage to the auditory area leads to possible hearing loss.
Describe the language areas of the brain
The language area seems to only exist in the left hemisphere (for most people).
Paul Broca identified an area in the left frontal lobe known as Broca’s area, which is responsible for speech production. Damage to this leads to a lack of ability to speak fluently and clearly- a condition known as Broca’s aphasia. An extreme example of this was one of Broca’s patients, who could only say the word ‘tan’.
Karl Wernicke identified a region in the left temporal lobe known as Wernicke’s area, which is responsible for language comprehension. When damaged, a person may say nonsense words. This condition is known as Wernicke’s aphasia.
Evaluate localisation of function - Broca & Wernicke
Petersen et al (1988) found that Wernicke’s area was active when performing listening tasks, and Broca’s area was active when undertaking reading tasks. This supports the idea that different areas of the brain have specific functions.
Evaluate localisation of function - Phineas Gage
The case of Phineas Gage (1848) supports localisation of function. Gage suffered an accident when a large metal pole was forced up through his head following an industrial accident, removing most of his left frontal lobe. Amazingly, he survived, his personality changed- he became short-tempered and rude. This suggests that mood regulation may be the responsibility of the frontal lobe.
Evaluate localisation of function - OCD
Dougherty et al (2002) found that a third of OCD sufferers who had part of the cingulate gyrus removed from their brain showed improvement in symptoms following the procedure. This, and similar studies of neurosurgery, shows that particular areas of the brain may be responsible for specific behaviours.
Evaluate localisation of function - beta bias
Some psychologists argue that the idea of localisation fails to take into
account individual differences. Herasty (1997) found that women have
proportionally larger Broca’s and Wernicke’s areas than men, which can perhaps
explain the greater ease of language use amongst women. This, however, suggests
a level of beta bias in the theory: the differences between men and woman are
ignored, and variations in the pattern of activation and the size of areas observed
during various language activities are not considered.
Outline what is meant by localisation
Scientists such as Broca and Wernicke discovered in the 19th century that, contrary to the previous explanations, specific areas of the brain are associated with particular functions and behaviours. Prior to this, the holistic theory suggested that the brain worked as a whole to undertake all tasks, activities and behaviours.
