Bit busy, but if you check out the work by julian jaynes on the little voice in your head it'll blow ya mind.

Basically he reckons that in olden times the voice in the head, the whole internal self-monitoring discussed by vygotsky, was labelled not as your own but as 'the gods'.
Basically you've got a whole bunch of greeks that by modern day standards are schizophrenic! Cool.

Nick