bicameralism
n. a highly controversial theory of primitive human mentality (posited to predate the development of consciousness) in which cognitive functions are divided between one hemisphere of the brain that “speaks” or “orders,” specifically through auditory hallucination, and another hemisphere that “listens” or “obeys.” The concept, proposed by U.S. psychologist Julian Jaynes (1920–1997) in his 1976 book The Origins of Consciousness in the Breakdown of the Bicameral Mind, has not received significant attention in neuropsychological research, although analogies have been drawn to neurological models describing the differing functions of the right and left hemispheres of the brain. The evolutionary aspect of the hypothesis contradicts current evidence about the origins of brain structures for consciousness and language.