Bicameral mentality

Bicameral mentality is a psychological hypothesis proposed by American psychologist Julian Jaynes. It suggests that early modern humans experienced thoughts and emotions not as originating within themselves but as commands from external "gods". According to the theory, the human mind once functioned with a division in which one part generated verbal instructions while a second part obeyed, forming a "bicameral mind". The eventual collapse of this mental structure is proposed to have led to the development of self-reflective consciousness in humans.

The term was coined by Jaynes, who presented the idea in his 1976 book The Origin of Consciousness in the Breakdown of the Bicameral Mind, wherein he makes the case that a bicameral mentality was the "normal and ubiquitous state" of the human mind as recently as 3,000 years ago, at the end of the Bronze Age.