Figure 5.30: Testing apparatus for subjects with split brains With this apparatus, it is possible to flash a stimulus in either visual field (or in both at once) and to ask the person to identify objects by touch with either hand. With the image of a pencil flashed in his left visual field, this subject with a split brain will be able to identify the pencil by touch with his left hand. Vocally, however, he will report having seen an apple on the screen, as that was flashed in his right visual field, which projects to his left, speaking hemisphere.

(Adapted from Gazzaniga, 1967, by permission of Michael S. Gazzaniga.)