here. Thus, the aphasia that develops from the lack of functioning of the Broca’s area is an expressives and non-fluent aphasia. It is called ‘non-fluent’ due the issues that arise because Broca’s area is critical for language pronunciation and production. The area controls some motor aspects of speech production and articulation of thoughts to words and as such lesions to the area result in the specific non-fluent aphasia.
Wernicke’s aphasia is the result of damage to the area of the brain that is commonly in the left hemisphere above the sylvian fissure. Damage to this area causes many deficits in language production and cognition. Although the speech produced by a person with Wernicke’s aphasia sounds like regular speech, it is riddled with mistakes. They include mild impairments in word selection, grammar, and segmental phonology. Wernicke's aphasia is characterized by phonemic paraphasias, neologism or jargon. Comprehension of spoken language is also mildly impaired in people with Wernicke's aphasia. Another characteristic of a person with Wernicke’s aphasia is that they are unconcerned by the mistakes that they are making.
Misapplication of concept
Terence Hines states that the research on brain lateralization is valid as a research program, though commercial promoters have applied it to promote subjects and products far outside the implications of the research. For example, the implications of the research have no bearing on psychological interventions such as EMDR and neurolinguistic programming, brain training equipment, or management training.
Advantages of brain lateralization
The widespread lateralization of many vertebrate animals indicates an evolutionary advantage associated with the specialization of each hemisphere. In one experiment, baby chicks were lateralized before hatching by exposing their eggs to light. These chicks were set to a task of picking out food from a bed of pebbles. Neither the lateralized, nor the non-lateralized chicks had a problem with this task, but the lateralized chicks only used the eye on the side of which they were lateralized to pick up the pebbles. When presented with a second task of watching for a cutout of a predatory hawk, the discrepancy between lateralized and non-lateralized chicks became evident. Lateralized chicks could pick food out of the pebbles with one eye and one half of the brain while using the other eye and other half of their brain to monitor the skies for predators. Not only could non-lateralized chicks not complete the two tasks simultaneously, but their performance of the single task deteriorated. This suggests that the evolutionary advantage of lateralization comes from the capacity to perform separate parallel tasks in each hemisphere of the brain. It was found in a 2011 study published in the journal of Brain Behavioral Research that lateralization of few specific functions as opposed to overall brain lateralization is correlated with parallel tasks efficiency.
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