Saken är den att vi verkar ha två olika viljor, en i vardera hemisfär.
Jag rekommenderar dig att läsa den här artikeln:
http://www.humantruth.info/split_brain.html
Där finns lite samlad information med stöd från litteratur.
"Split-brain patients have undergone surgery (normally in the treatment of epilepsy) to cut their corpus callosum, which normally joins the two hemispheres and allows an exchange of information from one to the other. While the surgery may relieve the suffering, it has a major side-effect in that the two hemispheres become functionally separate [...]. [In one example experiment involving] sets of photographs of different faces - a beautiful young female model, a podgy-cheeked boy [...]. They were then presented in such a way that the left side of the photo would only be visible to the right hemisphere and vica-versa. [...] Participants were asked to describe what they had seen (the left hemisphere responding): they said 'an old man'. But if asked to point with their left hand to the complete person of the person they had seen (the right hemisphere responding) they would point to the young boy. It seems that two completely separate visual worlds can exist within the same head!"
Bra att veta, vänstra hemisfären kontrollerar vår högra arm (t.ex.) och vice versa.