Biopsychology Evaluations

Question 1

Localisation of Function: Evidence from Neurosurgery

Answer 1

A strength of localisation theory is that damage to areas of the brain have been linked to mental disorders. Neurosurgery has been used for treating mental disorders by targeting specific areas of the brain.For example, Dougherty et al reported on 44 people with OCD who had undergone a cingulotomy. At post-surgical follow-up after 32 weeks, about 30% had met the criteria for successful response and 14% for partial response. The success of these procedures suggests that behaviours associated with serious mental disorders may be localised.

Question 2

Localisation of Function: Evidence from Brain Scans

Answer 2

A strength of localisation theory is evidence from brain scans which support the idea that many everyday brain functions are localised. For example, Petersen et al used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task. Also, Tulving et al revealed that semantic and episodic memories reside in different parts of the prefrontal cortex. These studies confirm localised areas for everyday behaviours and due to the objective methods used, provide sound scientific evidence that many brain functions are localised.

Question 3

Localisation of Function: Contradictory Research Evidence

Answer 3

A weakness of localisation theory is that not all research evidence supports its claims. For example, Lashley removed areas of the cortex (between 10% and 50%) in rats learning the route through a maze. No area was proven to be more important than any other area in terms of the rats’ ability to learn the route. The process of learning seemed to require every part of the cortex rather than being confined to a particular area. This suggests that higher cognitive processes, such as learning, are not localised but distributed in a more holistic way in the brain.

Question 4

Localisation of Function:Language Localisation Questioned

Answer 4

A weakness of localisation theory is that language may not be localised just to Broca’s and Wernicke’s areas. Dick and Tremblay found that only 2% of modern researchers think that language in the brain is completely controlled by these areas. Advances in brain imaging techniques mean that neural processes in the brain can be studied with more clarity. Language function seems to be distributed far more holistically in the brain than first thought. This suggests that, rather than confined to a couple of key areas, language may be organised more holistically in the brain, contradicting localisation theory.