Lateralisation- split brain research Flashcards
What have split brain patients had done to them?
Had their connection between the left and right hemisphere severed (their corpus collosum has been cut)
What are functions of the left side of the brain?
- Right side of body control
- Math/ science skill
- Written/ spoken language
What are functions of the right side of the brain?
- Left side of body control
- Music/ art awareness
- Face recognition
When testing split brain patients, words were projected to the left visual field (so went to the right hemisphere).
What was this testing, what did it find, and what does it suggest about hemispheric functioning?
TESTING- Verbal responses to language
FINDINGS- Words didn’t seem to be registered (participants would say they hadn’t seen anything)
SUGGESTS- The left hemisphere is responsible for language, so words need to be presented to the right visual field in order to be registered
When testing split brain patients, a word was projected to the left visual field, but the left hand was placed behind a screen and then had to select the object from a number of items.
What was this testing, what did it find, and what does it suggest about hemispheric functioning?
TESTING- Physical responses to language
FINDINGS- Participants could select the correct object despite being unable to verbally report seeing it.
SUGGESTS- Right hemisphere has some language ability for understanding words if not speech.
When testing split brain patients, a different face was presented to each hemisphere at the same time, participants were then given a set of faces and asked to select those they’d seen.
What was this testing, what did it find, and what does it suggest about hemispheric functioning?
TESTING- Matching abilities in response to pictures
FINDINGS- Participants chose the one presented to the right hemisphere, indicating its role in identifying faces and shapes.
SUGGESTS- Right hemisphere is responsible for visuo spatial tasks.
If the point is:
A strength of split brain research is that it has useful practical applications, enabling a greater understanding of the differing functions of the hemispheres.
What is the evidence, explanation and link?
Evidence- For instance, we now know that language is largely processed in the left hemisphere, because participants could select the correct object, despite being unable to verbally report seeing it.
Explanation- This suggests that the right hemisphere has some language ability for understanding words, if not speech, as words were projected to the left visual field.
Link- This allows our scientific understanding of the brain to move forward from split brain research.
If the point is:
However, a weakness of split brain research is that it lacks generalisability, as there was a limited number of participants.
What is the evidence and link?
Evidence- In addition, the participants varied considerably in age, gender and handedness as well as the age at which they developed epilepsy and the degree of drug therapy they had experienced before their operation. These are all factors that will affect behaviour.
Link- This implies that split brain research may not be applicable to all people, and hasn’t been compared to other groups, so should be analysed with caution.
If the point is:
A weakness of split brain research is that the patients were often compared to neurotypical controls.
What is the explanation and link?
Evidence- However, these people often had no history of epilepsy and therefore this could be a potential confounding variable, as a history of epilepsy would effect general behaviour.
Link- This means it’s harder to establish cause and effect and there could be other explanations for split brain findings, such as how the brain is effected by having epilepsy for a certain amount of years.
If the point is:
Another strength of split brain research is that the research has added to the consciousness debate.
What is the evidence and link?
Evidence- Split brain research has bought into debate what it means to be conscious. Previously, everyone assumed that consciousness was needed with full awareness, however split brain patients don’t have full awareness of information to both hemispheres.
Link- This suggests more research is needed into this area to define what human consciousness is.
What are the evaluations for split brain research?
+ It has useful practical applications, enabling a greater understanding of the different functions of the hemispheres
— It lacks generalisability as there was a limited number of participants
— The patients were often compared to neurotypical controls
+ The research has added to the consciousness debate
