Briefly evaluate research using split brain patients to investigate hemispheric lateralisation of function (4 marks).

A strength of this kind of research is the scientific nature and the fact that it provides empirical evidence that can be replicated, due to Sperry's research being standardised. However, split brain research is largely based off of case studies. This makes it an idiographic approach which cannot necessarily be generalised to the wider population. A further issue of population validity comes from the fact that split brain patients are all epileptic. Therefore, there could potentially be differences in their experiences, that there may not be in the general population.