Bicameral mentality is a hypothesis introduced by Julian Jaynes who argued human ancestors as late as the ancient Greeks did not consider emotions and desires as stemming from their own minds but as the consequences of actions of gods external to themselves.
The bicameral mind thus lacks metaconsciousness, autobiographical memory, and the capacity for executive "ego functions" such as deliberate mind-wandering and conscious introspection of mental content.
[8] The neurological model in The Origin of Consciousness in the Breakdown of the Bicameral Mind is a radical neuroscientific hypothesis that was based on research novel at the time, mainly on Michael Gazzaniga's split-brain experiments[9][10] and left-brain interpreter theory.
[13] Jaynes built a case for this hypothesis that human brains existed in a bicameral state until as recently as 3,000 years ago by citing evidence from many diverse sources, including historical literature.
[14] Citing Dodds, Snell, and Adkins,[15] Jaynes proposed 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 that were recorded in ancient myths, legends, and historical accounts.
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.
[14] Recent evidence shows that many people with schizophrenia do not just hear random voices but experience "command hallucinations" instructing their behavior or urging them to commit certain acts, such as walking into the ocean, which the listener feels they have no choice but to follow.
Jaynes also argues that people with schizophrenia feel a loss of identity due to hallucinated voices taking the place of their internal monologue.
The Late Bronze Age collapse of the 2nd millennium BCE led to mass migrations and created a rash of unexpected situations and stresses that required ancient minds to become more flexible and creative.
[19] 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.
[14] 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.
[21] Early coverage by Sam Keen in the November 1977 issue of Psychology Today considered Jaynes's hypothesis worthy and offered conditional support, arguing the notion deserves further study.
[22][23] The Origin of Consciousness in the Breakdown of the Bicameral Mind was a successful work of popular science, selling out the first print run before a second could replace it.
[15] It received dozens of positive book reviews, including those by well-known critics such as John Updike in The New Yorker, Christopher Lehmann-Haupt in the New York Times,[24] and Marshall McLuhan in the Toronto Globe and Mail.
[29] 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 José Luis Bermúdez.
[31][32][33] Gary Williams defends the Jaynesian definition of consciousness as a social–linguistic construct learned in childhood, structured in terms of lexical metaphors and narrative practice,[33] against Ned Block's criticism that it is "ridiculous" to suppose that consciousness is a cultural construction,[34] while the Dutch philosophy professor Jan Sleutels offers an additional critique of Block.
[42] 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:[43] "If we are going to use this top-down approach, we are going to have to be bold.
"[44] Danish science writer Tor Nørretranders discusses and expands on Jaynes's theory in his 1991 book The User Illusion, dedicating an entire chapter to it.
"[47] 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!
"[49] In 2007, Cavanna, Trimble, Cinti and Monaco wrote in Functional Neurology that "Even today, it has been argued that a multidisciplinary approach to the problem of consciousness and its development in the evolutionary process that shaped Homo sapiens cannot leave out an analysis of Jaynes' theory of the origin of consciousness in the breakdown of the preconscious bicameral mind",[13] citing Canadian psychologist, neuroanthropologist, and cognitive neuroscientist Merlin Donald[50] and American psychiatrist Stanley Greenspan.