some mental processes are specialised in one hemisphere only e.g. language
each hemisphere has its own functional specialisations
LEFT: speech and language
RIGHT: visual- motor tasks
the hemispheres are connected by the corpus callosum (a bundle of nerves)
allows interaction and transfer of information
hemispheric lateralisation strenghts
increases neural processing capacity
by only using one hemisphere to engage in a task, the other hemisphere is free to engage in a idfferent function
ROGERS found in the little domestic chicken that lateralisation is associated with an enchamced ability to perfrom two tasks at once
hemispheric lateralisation strengths
RILEA found no sex differences in all categories investigated which demonstrates how the dominant hemispheres arent as dominant as one thought
split brain research aim
SPERRY AND GAZZANIGA
tested the capabilities of the separated hemispheres by sending visual info to just one hemisphere
becasue the right hemisphere receives info from the left
split brain research procedure
SPERRY AND GAZZALINGA
1. patients fixate on a dot in the middle of a screen, their hands are under the table and out of sight
2. imagfe appears in either left or right visual field and asked to respond
left hand response (controlled by right hemisphere)
verbal response (controlled by left hemisphere)
e.g. patient sees a dog in left visual field 'i saw a dog' as left hemisphere controls right visual field and has language centre and sees a cat in the left ' i see nothing'
right hemisphere controls left visula field but has no language centre
split brain research results
SPERRY AND GAZZANIGA
left hemisphere is responsible for speech and language
right hemisphere is responsible for visual spatial processing and facial recognition
connectivity between the hemispheres are as important as localised regional functions
split brain research strength
scientific - produced large amount of research findings
strong, scientific methodology
split brain research limitations
quantitative data
very few people undergo severing their corpus callosum and even less in modern time
confounding variable - language isn't restricted to the left hemisphere
how was SPERRY and GAZZANIGA'S research limited
by the small sample size of split-brain patients
there was very few people who had there corpus callosm severed
e.g. some patients had been disconnected for longer and the bran would have experienced different degrees of adaption to loss of functions