I would skeptical of environmental factors as the primary cause due to the pervasiveness of bicamerality, including Africa, Mesoamerica, the Far East, etc. It seems that auditory hallucinations likely evolved along with language.

Did language evolve before or after the near extinction event I ...

Dr. Khalid Sohail has posted an intoductory to OC on infidels.org.

https://infidels.org/kiosk/article/julian-jaynes-theory-of-the-evolution-of-human-consciousness-813.html

The write-up is featured on their front page at the moment.

Edited to add that Dr. Sohail's article can also be found on his ...

Hi,

Since reading OC I must say that it really answers a lot of questions I have had about the origins of human consciousness and religion, but I have a little trouble accepting that bicamerality was once our natural state. Is it possible that bicamerality may have been a temporary state induced by ...