Dual Brain Theory

Julian Jaynes describes an earlier mentality prior to the development of subjective consciousness called the bicameral mind, in which the brain’s hemispheres operated in a less integrated manner than they do today. Jaynes argues that the brain used language to convey experience in the right hemisphere to the left hemisphere in the form of what we would today call an auditory hallucination. Studies from both split-brain and hemispherectomy patients have confirmed that the brain hemispheres can operate both independently and in isolation. Below is a small sample of research supporting this aspect of Jaynes’s theory.

Articles

Books

The Dual Brain: Hemispheric Specialization in Humans

The Dual Brain: Hemispheric Specialization in Humans
Benson, D.F. and Eran Zaidel (eds.) (The Guilford Press, 1985)
Contributors to this volume have investigated and demonstrated a number of processes that function asymmetrically within the two hemispheres of the brain. This includes research concerning the extent to which cerebral hemispheres constitute distinct and complete cognitive systems with different perceptions, memories, problem-solving strategies, and personalities. The wide-ranging implications, as well as the apparent limitations, of dual brain theory are covered in detail.

Laterality: Functional Asymmetry in the Intact Brain
Bryden, M.P. (New York: Academic Press, 1982)

The Double Brain

The Double Brain
Dimond, Stuart J. (Edinburgh and London: Churchill Livingstone, 1972)
“New avenues for investigating fundamental aspects of brain organization are rarely opened up. Yet the last 10 years have witnesses fascinating developments in neuropsychology with techniques for studying the functions of each cerebral brain hemisphere independently of the other. In fact, it can prove useful to view the brain not as a single organ but as two units, left and right, each specialized in certain distinctive ways. …”

Functions of the Corpus Callosum
Ettlinger, E.G. (Boston: Little Brown, 1965)
Cited by Jaynes on p. 105.

Medicine, Mind, and the Double Brain: A Study in Nineteenth-Century Thought

Medicine, Mind, and the Double Brain: A Study in Nineteenth-Century Thought
Harrington, Anne (Princeton University Press, 1987)
“Anyone interested in the differences in function between the left and right brain hemispheres will find Anne Harrington’s historical account a freshening and sobering revelation. Far from being a new field of neuroscience, cerebral laterality was the center of significant and impassioned controversy in the latter half of the nineteenth century, with ramifications into ideas of education, femininity, madness and a swarm of other contentious issues, often with the same arguments and overtones we hear today. This is a major contribution: accurate, fascinating, and important.” ― Julian Jaynes, author of The Origin of Consciousness in the Breakdown of the Bicameral Mind

The Asymmetrical Brain

The Asymmetrical Brain
Hugdahl, K. and R.J. Davidson (The MIT Press, 2004)
The folk belief that the left brain hemisphere is dominant for language and the right for visuospatial functions is incomplete and even misleading. Research shows that asymmetries exist at all levels of the nervous system and apply to emotional as well as to higher cognitive processes. Going beyond the authors’ previous book, Brain Asymmetry, this book reflects the most recent thinking on functional asymmetries and their structural correlates in brain anatomy. It emphasizes research using new neuroimaging and neurostimulation techniques such as magnetic resonance imaging (MRI and fMRI), positron emission tomography (PET), magnetoencephalography (MEG), and transcranial magnetic stimulation (TMS). It also considers clinical applications of asymmetry research. The book contains sections on animal models and basic functions, neuroimaging and brain stimulation studies, visual laterality, auditory laterality, emotional laterality, neurological disorders, and psychiatric disorders.

Commissurotomy, Consciousness, and Unity of Mind

Commissurotomy, Consciousness, and Unity of Mind
Marks, Charles E.(The MIT Press, 1981)
“This is a superb monograph. It raises the debate on the philosophical issues connected with split-brain research to a much higher level than before. That the split brain case is philosophically perplexing is undeniable; a description of the experiments of Sperry and others strikes not only philosophers but philosophy students and laymen as raising significant issues about what it is to have a single mind. The split brain cases have come to play a role in philosophy classes like that of other cases which are about equally puzzling but wholly fictional. Marks’ piece is a major advance…It would be a terrific choice for a course on the philosophy of psychology or for a seminar in philosophy or psychology.” ― John R. Perry, Stanford University

Speech and Brain-Mechanisms
Penfield, Wilder and Lamar Roberts (Princeton: Princeton University Press, 1959)
Cited by Jaynes on p. 101.