Psychosis - another reason to be anti-theist

[watchamadoodle]

Would that be more to do with the fact that those societies don't understand what's happening?

That is true. People with epilepsy, bipolar, or schizophrenia were assumed to be in the spirit world.

But I think there is another factor. Tribes were small enough that they could not afford to toss people aside for being different. Everybody probably had specialized skills (making spear points, etc.). There was much more incentive to accept odd behavior. Take the third gender for example ( http://en.wikipedia.org/wiki/Third_gender ).

When cities began to form, there would have been many people with each skill, so the weirdos could be burned at the stake when they threatened the social order.