It's actually addressed in the paper; that's a real oversimplification of what people "hearing voices" are actually experiencing.
Listening to people talk about their voices, one is struck by the variety of the human voice-hearing experience. People experience many phenomena (Tuttle, 1902). They hear scratching and whispering and murmurs loud enough to hear but too indistinct to under-stand. They hear noise that resolves into voices, so that words seem to slough off cars as they pass. They are sometimes clear and precise about exactly what they hear and some-times frustratingly vague. They report voices they clearly identify as external and voices they hear in their heads but do not experience as their own thoughts and thoughts and images that seem neither internal nor external but feel somehow impressed upon their awareness from outside. They talk about recognizing a single voice that seems to come out of more than one person, and about real people who say things they hear, but are not the words those people spoke. (“I know you are not speaking words of sex,” one man said, “but when you speak, words of sex are what I hear.”) In each of our settings, people reported this broad range of phenomena.
Listening to people talk about their voices, one is struck by the variety of the human voice-hearing experience. People experience many phenomena (Tuttle, 1902). They hear scratching and whispering and murmurs loud enough to hear but too indistinct to under-stand. They hear noise that resolves into voices, so that words seem to slough off cars as they pass. They are sometimes clear and precise about exactly what they hear and some-times frustratingly vague. They report voices they clearly identify as external and voices they hear in their heads but do not experience as their own thoughts and thoughts and images that seem neither internal nor external but feel somehow impressed upon their awareness from outside. They talk about recognizing a single voice that seems to come out of more than one person, and about real people who say things they hear, but are not the words those people spoke. (“I know you are not speaking words of sex,” one man said, “but when you speak, words of sex are what I hear.”) In each of our settings, people reported this broad range of phenomena.