Dual Brain Theory - History

History

The first instances of this theory began during the nineteenth century. According to the theory, every person has two perfectly formed brains, each of which can be substituted for the other in case of some traumatic, unilateral brain injury. In this time, it was thought that each side of the brain was associated with a specific gender: the left corresponding with masculinity and the right with femininity and each half could function independently. The right side of the brain was seen as the inferior and thought to be prominent in women, savages, children, criminals, and the insane. A prime example of this can be seen in Robert Louis Stevenson’s Strange Case of Dr. Jekyll and Mr. Hyde.

Scientists of the time disagreed on whether these cases of hemisphere imbalance could be cured, but some did believe that there was an analogy between muscular exertion and brain activity, meaning a person could physically strengthen one side of their brain.

These studies continued up until about the 1920s before they died out because psychiatrists turned to psychological explanations and neurologists emphasized holistic brain dynamics. The brain duality was revived though in the 1960s with Roger Sperry’s split-brain experiments. In one of Sperry’s studies, he showed a split-brain patient a picture to his right brain and the left hemisphere, responsible for verbal responses, could not articulate what was being seen. But the patient’s left hand, connected to the right brain, was able to give a thumbs-up or thumbs-down showing whether he approved of the picture or not.