Scientists have known for centuries that we "speak" with the left hemisphere of the brain. You perform an experiment in which your subject was presented with an apple only to the left visual field. When asked to identify what he saw, the subject denied seeing anything. However, when asked to point to the correct object, he was able to see and identify the apple. Which of the following is the most likely reason for this deficit?
A) The subject has a brain lesion in the frontal lobes.
B) The subject suffered head trauma to the back of his head.
C) The subject has a tumor in the left parietal lobe.
D) The subject had his corpus callosum severed to control epileptic seizures.

Question

Quizplus · Accepted Answer

The fact that the subject was able to correctly identify and point to the apple when it was presented only to the left visual field suggests that the information was processed in the right hemisphere of the brain but was not able to be communicated to the left hemisphere due to the corpus callosum being severed. This is a common deficit in patients who have had their corpus callosum severed to control epileptic seizures.

Scientists Have Known for Centuries That We "Speak" with the Left