Excerpts from "Voices in Your Head," Radiolab Blog, September 7, 2010:
Think about a small child sitting down solving a puzzle. If you watch any kid with their parent, anywhere in the world doing this kind of thing, you'll see them thinking together.
According to Lev Vygotsky, this is the beginning of thinking, this kind of dialogue. And at this point, it's completely external. It's all happening in that space between the child and her mother. And only over time does it become internalized.
And how that happens, Vygotsky thought, is as the child gets older, she'll start to take on the dialogue herself. She'll start to talk to herself. This is the stage we call private speech. We've all seen kids do this, right? Where they narrate every single thing they're doing. Put the ball in the box. Take the ball out of the box.
Now, what then happens in a few years further down the line, these kids who are narrating everything they're doing, then go to school and the teachers tell them, "Shh! Don't talk out loud." So they kind of get the message that they need to start doing this internally.
So they start to whisper to themselves out loud. And then eventually, they whisper to themselves silently. Because the words are now in their head. And that's, according to Vygotsky's theory, is thinking.
The logic of it is that all our thinking is full of other people's voices.
Clearly, for a lot of people, hearing voices involves some psychiatric issues, which sometimes can be serious. Really serious. But here's the weird thing: the experience of hearing somebody else's voice in your own head is actually way more common than you would think. Surveys have been done about this and the number seems to be between five and ten percent of normal, healthy people have that experience or have had it at one time. Which brings us back to this Vygotsky situation.
What might be happening in those cases, at least if you ask Charles Fernyhough, is a kind of misattribution of your own inner voice. Those voices in your head which are you get mistaken to be from someone else.
A nice, simple, elegant demonstration of this is that you take some people who are hearing voices—people, in this case, with the diagnosis of schizophrenia—and you sit them down at a microphone with some headphones on. You show them some words on a screen and their task is to repeat the words—to read the words out loud.
The trick is, the researchers have rigged it to that the voice in their headphones—their voice—actually gets lowered just a little bit right before they hear it.
What the experimenters found is that most people—most non-voice-hearing people—when they were presented with the sound of their own voice lowered and then asked, "Is this you or is it a stranger or are you not sure?" the voice hearers made considerably more mistakes. Not only that, but when they heard their voices lowered, they would very often say, "That voice is coming from a stranger. That's not me. That's not myself. That didn't from me." Now, of course, that is a potentially frightening experience.
But not always. Let's just imagine that Vygotsky was right, that the internal voice of our thoughts is actually a blend of all of those external voices from our childhood: our mom, our dad, our sisters, brothers, whatever. They're all in there in some way. And that can actually be a comfort.