|
Bicameralism (the philosophy of "two-chamberedness") is a hypothesis in psychology that argues that the human mind once assumed 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'', wherein he made the case that a bicameral mentality came to be the normal and ubiquitous state of the human mind until as recently as 3000 years ago. ''The Origin of Consciousness'' was financially successful, and has been reprinted several times. Originally published in 1976 (ISBN 0-395-20729-0), it was nominated for the National Book Award in 1978. It has been translated into Italian, Spanish, German, French, and Persian. 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 (ISBN 0-14-017491-5), re-issued in 2000. ==''The Origin of Consciousness''== 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. The 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 predictions. Jaynes built a case for this hypothesis that human brains existed in a bicameral state until as recently as 3000 years ago by citing evidence from many diverse sources including historical literature. He took an interdisciplinary approach, drawing data from many different fields. 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: the ancients figuratively heard muses as the direct source of their music and poetry. For example, 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. According to Jaynes, 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 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. Unlike today's hallucinations, the voices of ancient times were structured by cultural norms to produce a seamlessly functioning society. In Ancient Greek culture there is often mention of the Logos, which is a very similar concept. It was a type of guiding voice that was heard as from a seemingly external source. 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.〔 Jaynes notes that even in modern times 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 schizophrenics do not just hear random voices but experience "command hallucinations" instructing their behavior or urging them to commit certain acts. As support for Jaynes's argument, these command hallucinations are little different from the commands from gods which 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 recent book ''Muses, Madmen, and Prophets: Rethinking the History, Science, and Meaning of Auditory Hallucination'' by Daniel Smith. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bicameralism (psychology)」の詳細全文を読む スポンサード リンク
|