Split brain research Flashcards
Hemispheric Lateralisation
2 hemispheres function differently.
Certain behaviours and cognitive processes controlled by a particular hemisphere. (localisation and lateralisation of language)
Cross- lateralisation
left hemisphere controls the right side of the body & the right hemisphere controls left side of the body.
Sperry’s research
- 11 ppts who all experienced commissurotomy (corpus callosum cut to help control severe epileptic seizures).
- control group -> ppts without commissurotomy.
- Experiment -> different images/ words presented to each visual field (processed in opposite hemisphere.
- ppts had one eye blindfolded, focused on fixation point.
- stimulus material presented for 1/10 second to prevent eye movement + use of both visual fields.
Method
This method assumes that ‘normal’ brains communicate information between hemispheres to process a holistic view but information cannot be shared in split- brain patients.
Sperry’s research- findings 1
RECOGNITION BY TOUCH: object perceived in left visual field, information would be processed in RH- not connected to language centres. Hand placed under screen to identify object correlated to what they had seen. Language issue not lack of recognition.
findings 2
COMPOSITE WORDS: ppts saw key in left eye + ring with right eye. Info from RVF could be verbalised. Couldn’t verbalise info from LVF- could draw a key in response to what they had seen with left hand.
findings 3
MATCHING FACES: ppts shown a face in either visual field, shown a series of faces and asked to determine if any matched the first. If faces seen in LVF, ppts could pick the match but couldn’t verbalise. RVF vocalise- but couldn’t match.
Matching is verbalised, as is language.
findings 4
DESCRIBING WHAT YOU SEE: ppts shown object in LVF, ppt could not say what they had been shown. Shown in RVF, ppts could vocalise what they had been shown.
