AO3 - Split Brain Research

• A strength of split brain research is that it uses scientific methods. This is because it is based on objective and empirical techniques such as controlled laboratory settings. These are used in order to identify which hemisphere of the brain is responsible for which task, for example the split brain patients were only able to say what they saw when the image was presented to the right visual field, which suggests the left hemisphere is activated during language tasks. Arguably, this increases the overall internal validity of split brain research, thus raising Psychology’s scientific status.
• One limitation of the research is individual differences in the participants, in relation to how lateralised their brain was. The degree to which the corpus callosum was severed for each participant varied greatly with some having a greater disconnection between the two hemispheres than others. This is a weakness because the research may not be measuring the effects of lateralisation effectively which reduces the internal validity of split brain research.
• Moreover, research to contradict hemispheric lateralisation of the brain comes from a case study on a patient named EB. EB suffered from brain damage that resulted in the removal of his left hemisphere and therefore his language centres. Despite this, after some time EB managed to regain some of his language ability which would not be possible if the brain was completely lateralised. This demonstrates that language must be in more areas than just the left hemisphere, arguing against lateralisation of function in the brain.