A Level Psychology OCR Test 2026 – 400 Free Practice Questions to Pass the Exam

The independent variable in the Sperry et al. (1968) study is the presence or absence of split brain. This study focused on individuals who had undergone a surgical procedure to sever the corpus callosum, which connects the left and right hemispheres of the brain. By manipulating this variable, researchers could investigate how the two hemispheres operated independently, revealing significant insights into lateralization of brain function.

The design of the experiment allowed the researchers to compare the cognitive and perceptual functioning of split-brain patients to those with a normally functioning brain. By using this variable, the study was able to explore the effects of the brain's structural changes on behavior and information processing. A clear distinction in brain function between those with and without this severance was observed through a variety of tasks, demonstrating that the independent variable directly influenced the outcomes measured in the study.