The
1976 book
The Origin of Consciousness in the Breakdown of the Bicameral Mind, by
psychologist Julian Jaynes proposed that until the beginnings of
historic times
schizophrenia or a closely similar condition was the normal human mental state. A "bicameral mind" in which a normal state of low
affect suitable for routine activities would be interrupted in moments of crisis by "mysterious voices" giving instructions, which early people characterized as interventions from the
gods. This theory was widely discussed for a short time but continued work has not provided additional support for the idea.