It all started in 1961, when two neurosurgeons from Los Angeles, California made an assumption that epileptic seizures were caused by strange brain activity that went between the two hemispheres.They began with a hypothesis that explained they could reduce the seizures if they were able to cut the corpus callosum.

The surgeons at the time were very confident. They were confident because they had split the brains of cats and monkeys before. From what they analyzed the cats and monkeys had no real side effects that were present. Soon they completed the operation. The operation was a success. In the patients the seizures were removed and since the patients had split brains they did not act any different than before.


One experiment that has been done on the corpus callosum was completed almost ten years before the actual operation of cutting the corpus callosum. Karl Lashley believed that the corpus callosum was only in the brain to keep the two hemispheres together. He was proved wrong when Sperry and Gazzaniga conducted an experiment that showed millions of nerve fibers that ran through the corpus callosum between the two hemispheres.

They discovered that each hemisphere had a completely different function than the other one. If researchers were to test this on your average person that did not have a split-brain procedure on would find out that the information is processed in one of the hemispheres but then is immediately transported to the other hemisphere.

Later, another experiment was conducted by Gazzaniga. He asked patients that had the split-brain procedure to watch a dot that appeared on a screen between the E and A of HEART. So it looked like this HE*ART. Putting the dot there made the HE appear in their left visual field and ART in their right. The patients were asked to say what they saw and then point to it but it was the opposite side of the word. When asked to say what they say they said ART but when they were asked to point to it they pointed to HE


(Myers, 2007)
-psychology text book