Split Brain Research

Question 1

Split Brain

Answer 1

• Two hemispheres surgically separated by cutting the connections (the corpus callosum)
• Used to treat severe epilepsy to reduce the ‘electrical storm’ across hemispheres

Question 2

Sperry- Procedure

Answer 2

• Eleven spilt-brain participants were studied. An image or word would be projected to RVF (processed by LH), and same, or different, image could be projected to the LVF (processed by RH)
• Presenting the image to one hemisphere meant that the information could not be conveyed from that hemisphere to the other.

Question 3

Sperry- Findings

Answer 3

Object shown to RVF:
- Participant can describe what is seen (language centres in LH)
Object shown to LVF:
- Cannot name object (no language centres in RH)
- Cannot select matching objects behind screen using left hand
- Can select object closely associated with picture
- Pinup picture show to LVF, participant giggled but reported seeing nothing.

Question 4

Sperry- Conclusions

Answer 4

Demonstrates how certain functions of the brain are lateralised in the brain, shows that LH is verbal and the RH is ‘silent’ but emotional

Question 5

A03 (Support From More Recent Split-Brain Studies)

Answer 5

E- Luck et al. showed that split-brain participants were better than neurotypical controls e.g. twice as fast at identifying the odd one out in an array of similar objects. In the neurotypical brain, the LH’s superior processing abilities are ‘watered down’ by the inferior right hemisphere.
E- This supports Sperry’s earlier findings that the ‘left brain’ and ‘right brain’ are distinct in terms of functions and abilities

Question 6

A03 (Causal Relationship Are Hard To Establish)

Answer 6

E- In Sperry’s research the behaviour of the split-brain participants was compared to a neurotypical control group. However, none of the control group had epilepsy. Any differences between the groups may be due to epilepsy not the split-brain (a confounding variable).
E- This means that some of the unique features of the split-brain participants’ cognitive abilities might have been due to their epilepsy.

Question 7

A03 (Ethics)

Answer 7

E- Sperry’s participants were not deliberately harmed and procedures were explained in advance to gain informed consent. However, participants may not have understood they would be tested for many years, and participation was stressful.
E- This suggests that there was no deliberate harm but the negative consequences make the study unethical.