hemispheric lateralisation and split Flashcards
strength:methodology
E:research is conducted in a laboratory, under controlled conditions. Secondly, the standardised procedure allowed Sperry to present visual information to one eye, and therefore one hemisphere, at a time.
E - The use of controlled conditions allowed Sperry to carefully control for situational variables and the standardised procedure meant that Sperry had close control over the independent variable. As a result, split-brain research has high internal validity. This helps ensure we can trust its findings on hemispheric lateralisation.
limitation:challanged by conventional wisdom on lateralisation.
E – Kim Peek was born without a corpus callosum, meaning he lacked a connection between his left and right hemispheres. He demonstrated many extraordinary mental abilities, including being ableto read pages of a book in 8-10 seconds. He did this by reading the left page with his left eye and the right page with his right eye.
E – Peek’s ability to read with his left and right eyes despite lacking a corpus callosum challenges the claim that language is lateralised to the left hemisphere only. This is clear because if Peek is able to read with his left eye (which connects to his right hemisphere), then his right hemisphere also has the capacity to process language. However, this research is based on a single case study involving a very unique individual. As Kim Peek may not be representative of the wider population, this finding may only provides a weak challenge to the orthodox understanding of hemispheric lateralisation.
L – Therefore, the case of Kim Peek does provide a challenge to the findings of split-brain research on hemispheric lateralisation, albeit limited due the issues with generalising from case studies.
limitation:issues with generalisation
E – Split-brain research tends to involve small samples (Sperry’s original split-brain research was conducted on 11 split-brain patients) composed of participants who have undergone an extreme surgical procedure, usually as a last-resort treatment for severe epilepsy.
E – Generalising from these small and unique samples is difficult. This means that split-brain research may not tell us that much how hemispheric lateralisation works in non-split-brain patients. Consequently, its findings on hemispheric lateralisation may lack population validity. However, due to the unique nature of the split-brain condition, researchers don’t really have a choice about relying on these small and, arguably, unrepresentative samples.
L – Therefore, issues with the representativeness of split-brain patients may make it difficult to draw generalisable conclusions about hemispheric lateralisation.
