An alter ego (Latin, "the other I") is a second self, which is believed to be distinct from a person's normal or original personality. The term appeared in common usage in the early 19th century when dissociative identity disorder was first described by psychologists.Cicero was the first to coin the term as part of his philosophical construct in 1st century Rome, but he described it as "a second s
elf, a trusted friend". A distinct meaning of alter ego can be found in literary analysis, wherein it describes characters in different works who are psychologically similar, or a fictional character whose behavior, speech or thoughts intentionally represent those of the author. It's also used to design the best friend of another character in a story. Similarly, the term alter ego may be applied to the role or persona taken on by an actor or by other types of performers. The existence of "another self" was first recognized in the 1730s. Anton Mesmer used hypnosis to separate the alter ego. These experiments showed a behavior pattern that was distinct from the personality of the individual when he was in the waking state compared to when he was under hypnosis. Another character had developed in the altered state of consciousness but in the same body.
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