Bicameral mentality

Jaynes uses "bicameral" (two chambers) 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, nonconscious mental schema wherein volition in the face of novel stimuli was mediated through a linguistic control mechanism and experienced as auditory verbal hallucinations. Definition Bicameral mentality is nonconscious 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 thus lacks metaconsciousness, autobiographical memory, and the capacity for executive "ego functions" such as deliberate mind-wandering and conscious introspection of mental content. When bicameral mentality 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 experienced the world in a manner that has some similarities to that of a person with schizophrenia. Rather than making conscious evaluations in novel or unexpected situations, the person hallucinated a voice or "god" giving admonitory advice or commands and obeyed without question: one was not at all conscious of one's own thought-processes . Jaynes's hypothesis is offered as a possible explanation of "command hallucinations" that often direct the behavior of those with first-rank symptoms of schizophrenia, as well as other voice-hearers. Influences Regarding Homeric psychology Eric Robertson Dodds wrote about how ancient Greek thought may have not included rationality as defined by modern culture. In fact, the Greeks may have known that an individual did things, but the reason they did things was attributed to divine externalities, such as gods or daemons. Bruno Snell in 1953 thought that in Homeric Greek psychology there was no sense of self in the modern sense. Snell then describes how Greek culture "self-realized" the modern "intellect". , building on Snell's work, wrote about how ancient Greek civilization developed ego-centered psychology as an adaptation to living in city-states, before which the living in Homeric oikos did not require such integrated thought processes. Regarding neurological models 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 and left-brain interpreter theory. The more general idea of a "divided self" (contrasted with a "unitary self") has found support from psychological and neurological studies. Jaynes's evidence 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. He took an interdisciplinary approach, drawing data from many different fields. Citing Dodds, Snell, and Adkins, 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. This is exemplified in not only the commands given to characters in ancient epics but also the very muses of Greek mythology who "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 that 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. In ancient times, Jaynes noted, gods were generally much more numerous and much more anthropomorphic than in modern times, and he speculates that this was because each bicameral person had their own "god" who reflected their own desires and experiences. 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. This adaptation to the village communities of 100 individuals or more formed the core of religion. Citing Gazzaniga, 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. Jaynes noted that some studies show that auditory hallucinations correspond to increased activity in these areas of the brain. 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. 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. As support for Jaynes's argument, these command hallucinations are little different from the commands from gods that feature prominently in ancient stories. Indirect evidence supporting Jaynes's theory that hallucinations once played an important role in human mentality can be found in the 2007 book Muses, Madmen, and Prophets: Rethinking the History, Science, and Meaning of Auditory Hallucination by Daniel Smith. Breakdown Jaynes theorized that a shift from bicameral mentality 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 2nd millennium BCE. 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 Maya—as changes in the environment strained the sociocultural equilibria sustained by this bicameral mindset. 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. 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 bicameral mentality, emerged as a neurological adaptation to social complexity in a changing world. 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. 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. Leftovers of the bicameral mind today, according to Jaynes, include mental illnesses such as schizophrenia. Jaynes says that there is no evidence of insanity existing prior to the breakdown of the bicameral mind and that this is indirect evidence for his theory. He considered that previous claims of insanity in Homeric literature are based on mistranslations. ==Reception and influence==