Evaluation

• Evidence from neurosurgery - s- Damage to areas of the brain has been linked with mental disorders. Neurosurgery is the last resort for treatment of mental disorders targeting specific areas of the brain potentially involved. For example, the cingulate gyrus, had been implicated with OCD. Dougherty et al (2002) reported 44 people with OCD who'd undergone a cingulotomy. During the follow-up after 32 weeks, 30% had met the criteria for a successful response and 14% for partial response. This suggests that behaviours associated with serious mental disorders may be localised.
• Evidence from brain scans - s- Brain scans have supported the idea that many everyday brain functions are localised. eg. Peterson (1988) demonstrated how Wernicke's area was active during listening tasks and Broca's area was active during reading tasks. Moreover, a review of long term memory studies by Buckner and Petersen (1996) revealed that semantic and episodic memories reside in different parts of the prefrontal cortex. These studies support localisation with scientific evidence.
• Counterpoint for brain scan evidence - Lashley (1950) removed 10-50% of the cortex in rats that were learning the route through a maze. No area was proven to be more important in learning than other areas, instead, learning required every part of the cortex rather than being confined to a particular area. This suggests cognitive processes may be distributed in a more holistic way in the brain than localised.
• x- Language may not just be localised to Broca and Wernicke's area. A recent review by Dick and Tremblay (2016) found language to be distributed more holistically with the emergence of neuroscience and scanning techniques such as fMRI's. It was found that only 2% of modern researchers believe language in the brain is completely controlled in Broca and Wernicke's area. This suggests that rather than being confined to some key areas, language may be more holistic eg. language streams identified in the thalamus.