Bicameralism (the condition of being divided into "two-chambers") is a hypothesis in psychology that argues that the human mind once operated in a state in which cognitive functions were divided between one part of the brain which appears to be "speaking", and a second part which listens and obeys a bicameral mind. The term was coined by Julian Jaynes, who presented the idea in his 1976 book The Origin of Consciousness in the Breakdown of the Bicameral Mind,[1] wherein he made the case that a bicameral mentality was the normal and ubiquitous state of the human mind as recently as 3,000 years ago, near the end of the Mediterranean bronze age.

Jaynes uses governmental bicameralism as a metaphor to describe a mental state in which the experiences and memories of the right hemisphere of the brain are transmitted to the left hemisphere via auditory hallucinations. The metaphor is based on the idea of lateralization of brain function although each half of a normal human brain is constantly communicating with the other through the corpus callosum. The metaphor is not meant to imply that the two halves of the bicameral brain were "cut off" from each other but that the bicameral mind was experienced as a different, non-conscious mental schema wherein volition in the face of novel stimuli was mediated through a linguistic control mechanism and experienced as auditory verbal hallucination.

Bicameral mentality would be non-conscious in its inability to reason and articulate about mental contents through meta-reflection, reacting without explicitly realizing and without the meta-reflective ability to give an account of why one did so. The bicameral mind would thus lack metaconsciousness, autobiographical memory, and the capacity for executive "ego functions" such as deliberate mind-wandering and conscious introspection of mental content. When bicamerality as a method of social control was no longer adaptive in complex civilizations, this mental model was replaced by the conscious mode of thought which, Jaynes argued, is grounded in the acquisition of metaphorical language learned by exposure to narrative practice.

According to Jaynes, ancient people in the bicameral state of mind would have experienced the world in a manner that has some similarities to that of a schizophrenic. Rather than making conscious evaluations in novel or unexpected situations, the person would hallucinate a voice or "god" giving admonitory advice or commands and obey without question: One would not be at all conscious of one's own thought processes per se. Research into "command hallucinations" that often direct the behavior of those labeled schizophrenic, as well as other voice hearers, supports Jaynes's hypothesis.[2][not in citation given]

Jaynes built a case for this hypothesis that human brains existed in a bicameral state until as recently as 3000years ago by citing evidence from many diverse sources including historical literature. He took an interdisciplinary approach, drawing data from many different fields.[3] Jaynes asserted that, until roughly the times written about in Homer's Iliad, humans did not generally have the self-awareness characteristic of consciousness as most people experience it today. Rather, the bicameral individual was guided by mental commands believed to be issued by external "gods" commands which were recorded in ancient myths, legends and historical accounts. This is exemplified not only in the commands given to characters in ancient epics but also the very muses of Greek mythology which "sang" the poems. According to Jaynes, the ancients literally heard muses as the direct source of their music and poetry.

Jaynes asserts that in the Iliad and sections of the Old Testament no mention is made of any kind of cognitive processes such as introspection, and there is no apparent indication that the writers were self-aware. Jaynes suggests, the older portions of the Old Testament (such as the Book of Amos) have few or none of the features of some later books of the Old Testament (such as Ecclesiastes) as well as later works such as Homer's Odyssey, which show indications of a profoundly different kind of mentality an early form of consciousness.[3]

In ancient times, Jaynes noted, gods were generally much more numerous and much more anthropomorphic than in modern times, and speculates that this was because each bicameral person had their own "god" who reflected their own desires and experiences.[4]

He also noted that in ancient societies the corpses of the dead were often treated as though still alive (being seated, dressed, and even fed) as a form of ancestor worship, and Jaynes argued that the dead bodies were presumed to be still living and the source of auditory hallucinations.[3] This adaptation to the village communities of 100individuals or more formed the core of religion. Unlike today's hallucinations, the voices of ancient times were structured by cultural norms to produce a seamlessly functioning society.

Jaynes inferred that these "voices" came from the right brain counterparts of the left brain language centres; specifically, the counterparts to Wernicke's area and Broca's area. These regions are somewhat dormant in the right brains of most modern humans, but Jaynes noted that some studies show that auditory hallucinations correspond to increased activity in these areas of the brain.[3]

Jaynes notes that even at the time of publication there is no consensus as to the cause or origins of schizophrenia. Jaynes argues that schizophrenia is a vestige of humanity's earlier bicameral state.[3] Recent evidence shows that many schizophrenics do not just hear random voices but experience "command hallucinations" instructing their behavior or urging them to commit certain acts.[full citation needed]

As support for Jaynes's argument, these command hallucinations are little different from the commands from gods which feature prominently in ancient stories.[3] Indirect evidence supporting Jaynes's theory that hallucinations once played an important role in human mentality can be found in the recent book Muses, Madmen, and Prophets: Rethinking the History, Science, and Meaning of Auditory Hallucination by Daniel Smith.[5]

Jaynes theorized that a shift from bicameralism marked the beginning of introspection and consciousness as we know it today. According to Jaynes, this bicameral mentality began malfunctioning or "breaking down" during the 2ndmillenniumBCE. He speculates that primitive ancient societies tended to collapse periodically: for example, Egypt's Intermediate Periods, as well as the periodically vanishing cities of the Mayas, as changes in the environment strained the socio-cultural equilibria sustained by this bicameral mindset.

The Bronze age collapse of the 2ndmillenniumBCE led to mass migrations and created a rash of unexpected situations and stresses which required ancient minds to become more flexible and creative. Self-awareness, or consciousness, was the culturally evolved solution to this problem. This necessity of communicating commonly observed phenomena among individuals who shared no common language or cultural upbringing encouraged those communities to become self-aware to survive in a new environment. Thus consciousness, like bicamerality, emerged as a neurological adaptation to social complexity in a changing world.[citation needed]

Jaynes further argues that divination, prayer, and oracles arose during this breakdown period, in an attempt to summon instructions from the "gods" whose voices could no longer be heard.[3] The consultation of special bicamerally operative individuals, or of divination by casting lots and so forth, was a response to this loss, a transitional era depicted, for example, in the book of 1 Samuel. It was also evidenced in children who could communicate with the gods, but as their neurology was set by language and society they gradually lost that ability. Those who continued prophesying, being bicameral according to Jaynes, could be killed.[6][7] Leftovers of the bicameral mind today, according to Jaynes, include religion, hypnosis, possession, schizophrenia, and the general sense of need for external authority in decision-making.[citation needed]

An early (1977) reviewer considered Jaynes's hypothesis worthy and offer conditional support, arguing the notion deserves further study.[8][9]

The Origin of Consciousness was financially successful, and has been reprinted several times.

Originally published in 1976[10] it was nominated for the National Book Award in 1978. It has been translated into Italian, Spanish, German, French, and Persian.[citation needed] A new edition, with an afterword that addressed some criticisms and restated the main themes, was published in the US in 1990 and in the UK by Penguin Books in 1993,[11] re-issued in 2000.[12]

Philip K. Dick, Terrence McKenna, and David Bowie all cited the book as an influence. [13]

Jaynes's hypothesis remains controversial. The primary scientific criticism has been that the conclusions drawn by Jaynes had no basis in neuropsychiatric fact.[14]

According to Jaynes, language is a necessary, but not a sufficient condition for consciousness: Language existed thousands of years earlier, but consciousness could not have emerged without language.[15] The idea that language is a necessary component of subjective consciousness and more abstract forms of thinking has gained the support of proponents including Andy Clark, Daniel Dennett, William H. Calvin, Merlin Donald, John Limber, Howard Margolis, Peter Carruthers, and Jos Luis Bermdez.[16]

Williams (2010)[17] defended Jaynes against the criticism of Block (1981).[18][clarification needed][clarification needed]

Asaad & Shapiro (1987)[19] questioned why Jaynes's theory was left out of a discussion on auditory hallucinations. The author's (1987) published response was: ...Jaynes hypothesis makes for interesting reading and stimulates much thought in the receptive reader. It does not, however, adequately explain one of the central mysteries of madness: hallucination. (Moffic, 1987)[14] However Moffic's claim that there is no evidence for involvement of the right temporal lobe in auditory hallucination was incorrect, even at the time that he wrote it.[20][21] More recently, a number of studies have provided more evidence of involvement of the right hemisphere in auditory hallucinations. The new evidence for Jaynes's model of auditory hallucinations arising in the right temporal-parietal lobe and being transmitted to the left temporal-parietal lobe that these neuroimaging studies provide was specifically pointed out by Olin (1999)[22] and by Sher (2000).[23] For further discussion, see Marcel Kuijsten (2007).[24]

Brian J. McVeigh (2007) maintains that many of the most frequent criticisms of Jaynes' theory are either incorrect or reflect serious misunderstandings of Jaynes' theory, especially Jaynes' more precise definition of consciousness. Jaynes defines consciousness in the tradition of Locke and Descartes as "that which is introspectable". Jaynes draws a sharp distinction between consciousness ("introspectable mind-space") and other mental processes such as cognition, learning, sensation, and perception. McVeigh argues that this distinction is frequently not recognized by those offering critiques of Jaynes' theory.[25]

Richard Dawkins in The God Delusion (2006) wrote of The Origin of Consciousness in the Breakdown of the Bicameral Mind:

It is one of those books that is either complete rubbish or a work of consummate genius; Nothing in between! Probably the former, but I'm hedging my bets.[26][pageneeded]

The philosopher Daniel Dennett suggested that Jaynes may have been wrong about some of his supporting arguments especially the importance he attached to hallucinations but that these things are not essential to his main thesis:[27]

If we are going to use this top-down approach, we are going to have to be bold. We are going to have to be speculative, but there is good and bad speculation, and this is not an unparalleled activity in science. ... Those scientists who have no taste for this sort of speculative enterprise will just have to stay in the trenches and do without it, while the rest of us risk embarrassing mistakes and have a lot of fun. Daniel Dennett[28]

Gregory Cochran, a physicist and adjunct professor of anthropology at the University of Utah, wrote:

"Genes affecting personality, reproductive strategies, cognition, are all able to change significantly over few-millennia time scales if the environment favors such change and this includes the new environments we have made for ourselves, things like new ways of making a living and new social structures. ... There is evidence that such change has occurred. ... On first reading, Breakdown seemed one of the craziest books ever written, but Jaynes may have been on to something."[29]

Author and historian of science Morris Berman writes: "[Jaynes's] description of this new consciousness is one of the best I have come across."[30]

Danish science writer Tor Nrretranders discusses Jaynes's theory favorably in his 1991 book.[31][vague]

James McGilchrist who published a similar idea, accepts Jayne's intention, but proposes that Jayne's hypothesis was the opposite of what happened:

I believe he [Jayne] got one important aspect of the story back to front. His contention that the phenomena he describes came about because of a breakdown of the 'bicameral mind' so that the two hemispheres, previously separate, now merged is the precise inverse of what happened.[32]:262

As an argument against Jaynes' proposed date of the transition from bicameralism to consciousness some critics have referred to the Epic of Gilgamesh.[citation needed] Early copies of the epic are many centuries older[33] than even the oldest passages of the Old Testament,[34] and yet it describes introspection and other mental processes that, according to Jaynes, were impossible for the bicameral mind.

Jaynes noted that the most complete version of the Gilgamesh epic dates to post-bicameral times (7thcenturyBCE), dismisses these instances of introspection as the result of rewriting and expansion by later conscious scribes, and points to differences between the more recent version of Gilgamesh and surviving fragments of earlier versions: "The most interesting comparison is in TabletX."[12]:252 His answer, however, does not deal with the generally accepted dating of the "Standard Version" of the Gilgamesh epic to the later 2ndmillenniumBCE, nor does it account for the introspection that so often taken as characteristic of the "Standard Version" being thoroughly rooted in the Old Babylonian and Sumerian versions, especially so as our understanding of the Old Babylonian poem improves.[33][34][35]

Julian Jaynes' study is mostly based on the writings and culture of the Mediterranean and Near-Eastern regions, although he occasionally also refers to ancient writings of India and China.[36][a]

Jaynes' proposal does not explain how such bicameralism could also have been near totally lost at the same time across the whole planet and in the entire human species. In particular the aborigine culture was completely separated from the rest of the world from 4000BCE1600CE and appears today to be historically unchanged, but also self-conscious.[citation needed]

Divination is also considerably older than that date and the early writings he claims show bicamerality: The oldest recorded Chinese Writing was on oracle bones, meaning that divination arose at the same time or even earlier than writing, in Chinese society.[37][not in citation given]

While he said ancient societies engaged in ancestor worship before this date, non-ancient societies also engaged in it after that date; very advanced societies like the Aztecs and Egyptians mummified and deified rulers (see Pyramids and the philosopher Nezahualcoyotl). The Aztecs and Incans did so all the way up to their enslavement by the Spanish.[citation needed]

It is now known[citation needed] that the sense of agency is closely connected with lateralization: The left parietal lobe is active when visualizing actions by the self, while the right parietal lobe is active for actions by others. Additionally, Wernicke's area processes the literal meaning of language, while the homologous region in the right hemisphere processes the intent of a speaker.

It has been found[citation needed] that people with damage to the right inferior parietal cortex experience alien hand syndrome, as do people who have had a corpus callosotomy. This reverses the relationship between the right and left hemispheres posited by Jaynes' proposed bicameralism: It is the left hemisphere that is responsible for speech and the right hemisphere that is responsible for self-awareness.

VS Ramachandran proposes a similar concept, referring to the left cortical hemisphere as an "apologist", and the right cortical hemisphere as a "revolutionary".[citation needed]

In his book Neuroreality, Bruce E. Morton, Professor Emeritus at the University of Hawaii, similarly proposed such a concept.[citation needed]

Psychiatrist Iain McGilchrist reviews scientific research into the role of the brain's hemispheres, and cultural evidence, in his book The Master and His Emissary.[32] Similar to Jaynes, McGilchrist proposes that since the time of Plato the left hemisphere of the brain (the "emissary" in the title) has increasingly taken over from the right hemisphere (the "master"), to our detriment. McGilchrist, while accepting Jayne's intention, felt that Jayne's hypothesis was "the precise inverse of what happened" and that rather than a shift from bicameralism there evolved a separation of the hemispheres to bicameralism.[32](See McGilchrist quotation, above.)

Michael Gazzaniga pioneered the split-brain experiments which led him to propose a similar theory called the left brain interpreter.

Neuroscientist Michael Persinger, who co-invented the God helmet in the 1980s, believes that his invention may induce mystical experiences by having the separate right hemisphere consciousness intrude into the awareness of the normally-dominant left hemisphere.[38]

The Julian Jaynes Society was founded by supporters of bicameralism in 1997, shortly after Jaynes' death. The society published a collection of essays on bicameralism in 2007, with contributors including psychological anthropologist Brian J. McVeigh, psychologists John Limber and Scott Greer, clinical psychologist John Hamilton, philosophers Jan Sleutels and David Stove, and sinologist Michael Carr (see shi personator). The book also contains an extensive biography of Julian Jaynes by historian of psychology William Woodward and June Tower, and a foreword by neuroscientist Michael Persinger.[40]

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