Hemispheric Lateralisation Flashcards
What does the left hemisphere control?
Right side of the body
Number skills
Logic and reasoning
Is language always in the left hemisphere?
96% of right handers and 70% of left handers have left hemispheric dominance for language
What does the right hemisphere control?
Left side of body
Creativity
Emotion
Spatial
What is the Broca’s area?
Posterior portion of the frontal lobe of the left hemisphere which is critical for speech production. Broca found patients with deficits who could understand language but could not speak or write had lesions in their left frontal hemisphere whereas patients with damage in these areas on the right hemisphere did not have the same language problems. Not all words are affected - nouns and verbs seem to be fine but conjunctions and prepositions have major problems.`
What is Wernicke’s area?
Posterior portion of the left temporal lobe. People with Wernicke’s aphasia could speak but were unable to understand language. Wernicke proposed that language involves separate sensory and motor regions located in different cortical regions. The motor region, located in Broca’s area controls the mouth, tongue and vocal cords, hence involved in speech production. Sensory region, which is located in Wernicke’s area in close to regions of the brain responsible for auditory and visual input. In the Wernicke’s area it is recognised with language and associated with meaning.
Is there case study evidence to support Broca’s and Wernicke’s areas?
Demonstrated functions being lateralised to the left hemisphere. Tan could not produce language due to damage in the left hemisphere. Caused by damage to the Broca’s area.
Is there problems for using case study evidence to support hemispheric lateralisation?
Only specific to individuals concerned so may not be generalisable to others. Patient Tan.
Is there support from human clinical case studies to support hemispheric lateralisation?
Receptive aphasia (difficulty understanding spoken language) following damage to the Wernicke’s area is seen in many cases, suggesting functions in the brain are localised and lateralised
Is the theory of lateralisation biologically reductionist?
Cannot reduce complex brain function into one specific area. No evidence for 100% left hemisphere dominance as it is 96% for right handers and 70% for left handers. Need to use a more holistic approach.
Problems using post mortem examinations to explain hemispheric lateralisation?
Could pinpoint different areas of the brain involved with particular functions, it is not possible to then refine the understanding of these functions by getting participants to do further tasks.
