A split brain operation, used to treat epilepsy by cutting the corpus callosum (the bundle of nerves connecting the two hemispheres of the brain), has some interesting implications for creativity.
A duality of mind is readily demonstrable in split brain humans, and evidence is steadily accumulating that ongoing interhemispheric communication is incomplete in the intact brain. It is now certain that the corpus callosum can transfer high-level information from one hemisphere to another. When we take into account the well-established principle of hemispheric specialization, the alexithymia in spite of the impressive normality of split-brain humans in ordinary social situations, a physiologic explanation for at least some forms of creativity seems close at hand. What is required is a partial (and transiently reversible) hemispheric independence during which lateralized cognition can occur and is responsible for the dissociation of preparation from incubation. A momentary suspension of this partial independence could account for the illumination that precedes subsequent deliberate verification. From this point of view, we can understand better tile observation of Frederic Bremer, who wrote years ago that the corpus callosum subserves "the highest and most elaborate activities of the brain"--in a word, creativity.