Evaluation

• Research support - Gazzaniga showed that split brain research participants actually perform better than connected controls on certain tasks. eg. participants with split brains were faster at identifying the odd one out in an array of similar objects. Kingstone et al (1995) suggested in the normal brain, the left hemisphere's better cognitive strategies are watered down by the inferior right hemisphere supporting Sperry's findings of distinct left/right brain.
• Generalisation issues -x- hard to establish causal relationship between a single variable and a complex outcome. when sperry's split brain participants compared to a neurotypical control group, issue being no participants in the control group had epilepsy presenting as a major confounding variable, therefore differences may not be due to split brain but epilepsy only 11 participants.
• xtra - ethics - Split brain operation not performed for the purpose of the research (operation was already conducted), so participants were not deliberately harmed and all procedures explained and full consent obtained. but the trauma of the operation may have changed the internal state of participants so later, may not have understood the implications of what they agreed to and they were subject to repeat testing which may have been stressful overtime.
• Sperry's split brain patients were not exposed to harm and they gave consent. However, a very small sample size was used making it not generalisable and the control group had a confounding variable.