A01

• Hemispheric lateralisation explains how the two hemispheres are functionally different. Some functions are not lateralized, for instance the motor cortex appears in both hemispheres but is contralateral i.e. the left hemisphere (LH) controls the right side of the body. The visual cortex is contralateral and ipsilateral i.e. the right hemisphere (RH) receives information from the left visual field of the left eye and the right eye.
• Sperry investigated whether the hemispheres are lateralized using a sample of 11 patients who had undergone split-brain surgery, where their corpus callosum was removed (shares information between hemispheres). Sperry was able to present information to one hemisphere only, by briefly flashing a stimulus in either of the visual fields.
• Presenting a word (e.g. cat) in the left visual field (connected to RH) meant the patient wasn’t able to verbally express what he saw as the language centres are located in the LH. However, they were able to draw a picture of a cat, using their left arm (connected to their RH). Sperry concluded that some functions are indeed lateralized to the hemispheres, such as the left being more verbal.