lateralisation and split brain research Flashcards
what does the term lateralisation refer to
the two halves of the brain are not alike they both have ther own specific functions
what is the left hemisphere dominant in
language and speech production
what is the right hemishere dominant in
visual and motor tasks
how do the hemisphere interact
they communicate via the corpus callosum a bundle of nerve fibres that connect the left and the right hemispheres
what is special in those with severe epilepsy
their corpus callosum is severed to prevent communication between the two hemispheres , these split brain patients were studies to find information about each specific hemisphere
what did roger sperry and michael gazzabiga do
they studies the capabilities of the seperated hemisphere, they were able to send visual information to just one hemisphere at one time to study hemisphere lateralisation
what was the method of sperry and gazzaniga research
an image would be rojected on to the patients right visual field which is processed by the left hemisphere and an image is projected to the patients left visual field processed by the right hemisphere
what would happen in a normal brain with sperry and gazzangia study
the corpus callosum would share information between both hemispheres giving a complete picture of the world, but in a split brain patient information cannot travel from one hemisphere to the other.
what were the result if flashed to the right visual field
if dog was flashed and they were asked what they saw they will say dog this id because visual information is processed by the left hemiphere and the left hemisphere is dominant is language and speech tasks so vocally say dog
what were the results if dog flashed to the left visual field
the dog information will be processed by the right hemisphere howver they will be unable to say dog as the right hemisphere cannot communicate with the left hemisphere as the corpus callosum is severed which means the information cannot be gathered by the language centre which is in the left so cannot say name however they can draw with their left hand
what about left visual field and touch
when they see it their left visual field and then processed by the right hemisphere they can still identify it by touch throught the left hand as the right hemisphere is dominant in visual and motor tasks
what is sperry and gazinga research conclusion
the left hemisphere is broadly responsible for speech and language and the right hemisohere is responsible for visual spatial processing and facial expression, split brain research doesnt show functions being localised to specific reigions
what is a strength of application
it has practical application for example the left hemisphere is dominant in language nad speech and right is dominant in visual and motor tasks .
what is the evidence for practical application
this has lead to therapies and specific treatments that helps with the recovery of the hemisphere for example if you damage the left hemisphere you may be given speech and language therapy
what is the explanation of application
through our undertanding it has lead to effective rehabilitiation programme, that will help target a specific hemisphere to speed up recovery therefore effective in improving the lives of others.
what is the point of the pioneering method
one strength is that sperry and gazaniga have used an innovatove method through scientific study of split brain patents
what is the evidence of pioneering method
sperrys and gazzingas original method included a blindfolded patient that fixated on a dot as they flashed an image for a tenth of a second
what is the explanation for pioneering method
the use of objectiveness and operationalised variable such as time flashed on the screen allows replicability, this is a strength due to individually unique nature it is difficult to obtain such a standised method to use on all split brain patients , however their methods were very effectiove thus the scientific rigour findings and understanding of lateralisation is valid
what si the weakness of lateralisation and age
a weakness of lateralisation is that it changes with age, lateralisation function appears to not exactly stay the same thoughoput an individuals life but changes with ageing
what is the evidence for lateralisation and age
for example scaflarski found that language becomes more lateralised to the left hemisphere throughout childhood and adolescence but after the age of 25 lateralisation is decreased becomes more bilateral with each decade of life
what is the explanation of lateralisation and age
this is a weakness because bilateral suggest the s&g is incomplete as if lateralisation is the brains way of functioning it should be demonstrated in individuals of all ages thus if laterlisation is the brains way of functioning their conclusion is incomplete
what is the issue with genralisation
a weakness of research into split brain research that supports lateralisation is that it has issue with genralisability and internal validity
what is the evidence for issues with genralisability
sperrys and gazzingas experiment all 11 of the patients had a history of epileptic seizures , and when the corpus callosum was severed, some had connection between the left and right still intact.
what is the explanation for issues with genralisaability
this is a problem because the epilepsy may have altered the brain structure and functions of the patients brain therfore genralisation of these split brain patients to neurotypicals will be innacurate decreasing population valdiity also soem of the participants experienced more severed connection than others and some may have other connections and pathways like the anterior commissure therefore we cannot produce a cause and effect relationship due to individual differences thus decreasint the validity of applying the research to other [people
