hemispheric lateralisation + split-brain research Flashcards
true or false?
language is lateralised
true
in which hemisphere are the 2 main language centres located?
left hemisphere
give 3 examples of brain areas that are not lateralised
vision area
motor area
somatosensory area
what led to the suggestion that the LH is the analyser whilst the RH is the synthesiser?
RH can only produce basic words, but it contributes emotional context to speech
how does vision work?
what does this enable the visual area to do?
the left visual field (LVF) of both eyes is connected to the RH and the right visual field (RVF) of both eyes is connected to the LH
this enables the visual area to compare different perspectives from each eye
name one limitation of hemispheric lateralisation
the idea that the LH is the analyser and the RH is the synthesiser may be wrong
what did Nielsen et. al. study + provide evidence for within hemispheric lateralisation?
analysed brain scans from over 1000 people aged 7-29 + found that people used certain hemispheres for certain tasks
HOWEVER, there was no evidence for a dominant side within personality (e.g. artist’s brain/mathematician’s brain)
what does research suggest about hemispheric lateralisation within connected brains?
hemispheric lateralisation does occur in connected brains as well as split brains
HOWEVER, even in connected brains the 2 hemispheres process information differently
how did Fink et. al. use PET scans to identify which brain areas were active during a visual processing task?
when participants with connected brains were asked to observe global elements of an image (e.g. forest) regions of the RH were much more active.
when asked to observe the finer detail of an image (e.g. individual trees) specific areas of the LH were more dominant
who was Sperry’s sample?
11 split-brain patients
what was the set-up for Sperry’s procedure?
an image could be projected to a participant’s RVF (processed by LH) and the same/different image could be projected to their LVF (processed by RH)
what would a normal brain do if an image was only presented to one hemisphere?
the ‘corpus callosum’ would immediately share information between both hemispheres, giving a complete picture of the visual world
what would a split brain do if an image was only presented to one hemisphere?
information cannot be conveyed between both hemispheres as the brain is split
what would Sperry’s participants do when an object was shown to their RVF?
they could describe what was seen
what would Sperry’s participants do when an object was shown to their LVF?
why?
they said there was ‘nothing there’ - because in the connected brain, messages from RH are relayed to language centres in LH, but this isn’t possible in a split brain
what could Sperry’s participants do even when they couldn’t give verbal labels to objects projected to their LVF?
they could select a matching object out of sight using their left hand (which is linked to RH)
what is one conclusion from Sperry’s study?
these observations show how certain functions are lateralised in the brain and support the view that LH is verbal + RH is emotional
name one strength of split-brain research
there is further research support
name one limitation of split-brain research
there are issues with Sperry’s sample
what did Gazzaniga et.al. show that?
give an example
split-brain patients actually perform better than connected brains on certain tasks - e.g. they were faster at identifying the odd one out than connected brains
true or false?
Gazzaniga’s research supports Sperry’s findings that LH + RH are distinct
true
list 3 issues with Sperry’s sample
11 split-brain patients were put together as an experimental group, but some patients had experienced more disconnection than others
small sample size
the comparison groups didn’t have a history of epilepsy (whereas split-brain patients all had a history of epilepsy - which is why they had the split-brain operation)
