When you’re talking to yourself silently or arguing in your head, there are actual muscular movements in your larynx. It seems like it’s all in your mind but it is also a little bit in your body. Any time you’re mentally talking to yourself, your body is also physically talking a little bit.
As I am writing this post, I am silently sounding out the words and sometimes the thought for the next line. As my memory worsens, I find myself heading down the stairs to the basement and silently (or maybe even aloud!) saying to myself “socket wrench” over and over so that I don’t get down there and forget what it was I went there to get.
Psychologists call this phenomenon “inner speech.” It has been studied for at least a hundred years. The theory has been that we developed this through the internalization of our external/out-loud speech. If that’s true, then wouldn’t inner speech use the same mechanisms in the brain as when we speak out loud?
It was known in the early 20th century that inner speech is accompanied by tiny muscular movements in the larynx which could be detected using electromyography. Since the 1990s, neuroscientists using more sophisticated functional neuroimaging to show that the “Broca’s area” of the brain is active when we speak out loud and also during inner speech. Experiments that “disrupt” (Ouch!) the activity of this region interrupts both outer and inner speech.
What is the value of studying this phenomenon? The thought is that it may help us to understand more inner experiences, such as “hearing voices.” That particular oddity (technically called “auditory verbal hallucinations”) which you might associate with mystical or religious experiences or madness might turn out to be a form of inner speech. Maybe we just don’t know that these hallucinations are self-produced.
I have been hearing some inner voices lately. But that’s something for another article.
theguardian.com/science/blog/2014/aug/21/science-little-voice-head-hearing-voices-inner-speech by Peter Moseley, working with the Hearing the Voice project