Hemispheric lateralisation Flashcards
what is hemispheric lateralisation
The idea that the two hemispheres of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere.
Right and left hemispheres
The two main centres of language are only in the left hemisphere, Broca’s area in the left frontal lobe and Wernicke’s area in the left temporal lobe. We say language is lateralised – performed by one hemisphere rather than the other.
Many functions aren’t lateralised, for example vision, motor and somatosensory areas appear in both hemispheres
Evaluation of hemispheric lateralisation (brief)
strength - fink et al, connected brains
weakness - Nielsen et al, no dominant side
strength of hemispheric lateralisation
one strength is research showing that even in connected brains the two hemispheres process information differently. Fink et al (1996) used PET scans to identify which brain areas were active during a visual processing task. When participants were asked to attend to global elements of an image regions of the right hemisphere were much more active. When required to focus in on the finer detail, the specific areas of the left hemisphere tended to dominate. This suggests that, at least as far as visual processing is concerned, hemispheric lateralisation is a feature of the connected brain as well as the split brain
weakness of hemispheric lateralisation
one weakness is the idea of the left hemisphere as an analyser and right hemisphere as a synthesiser. There may be different functions in the LH and RH, but research suggests people do not have a dominant side of their brain which creates a different personality. Nielsen et al (2013) analysed brain scans from over 1000 people aged 7 to 29. He found that people used certain hemispheres for certain tasks, which provides evidence for lateralisation, but there was no evidence of a dominant side. This suggests that the notion of right or left brained people is wrong.
