This week we're thinking about how we think: the ways we talk to -- and with -- ourselves, why we do it at all, and what happens when some of us hear voices that aren't our own. We spend the hour with Charles Fernyhough, Professor of Psychology at Durham University, about his book "The Voices Within: The History and Science of How We Talk To Ourselves".

More links of interest:

Hearing The Voice, an interdisciplinary study of voice hearing. You can find their FAQ here.

Intervoice: The International Hearing Voices Network