The authors found that the different hallucinated "voices" of four
schizophrenic subjects reported over 1-3 weeks expressed semantic content
that was at least as persistent as clauses sampled from single 5-7-minute
conversational discourses of four comparison speakers. The high degree of
semantic recurrence of voices from one day to the next may contribute to
the mistaken belief that these experiences derive from a particular nonself
agent or speaker.