According to Mike Holderness
The Origin of Consciousness in the Bicameral Mind is in its own way one of the more bitingly rationalist books I’ve had the pleasure to meet. Its central proposition – that consciousness arose only some time after the Iliad stories were first told – caused outrage among classicists when it was first published in 1977. The underlying thesis is that before then everyone was a florid schizophrenic, instructed in their every move by insistent ‘voices’, which were named as gods. Can consciousness have arisen simply as a metaphor ‘I’, as a side-effect of a personal narrative? Is all religion a nostalgia for the divided (bicameral) mind?
Update: According to this
Nearly 1 in 10 seven- to eight-year-olds hears voices that aren’t really there, according to a new study.
But most children who hear voices don’t find them troubling or disruptive to their thinking, the study team found. “These voices in general have a limited impact in daily life,” Agna A. Bartels-Velthuis of University Medical Center Groningen in The Netherlands wrote in an email to Reuters Health.