Bite, Speech, and Identity (2015)

This is a post I wrote in 2015 exploring the relationship between how your mouth feels, how your inner thoughts sound, and your sense of self.

The mention of being intensely aware of my face during misophonic episodes seems to concur with research indicating that misophonia involves connectivity between auditory processing and orofacial motor areas (see The Motor Basis for Misophonia).

I have a theory about the way you create and hear your inner voice when you're thinking: you have a verbal thought, and as you think of each word, the speech part of your brain kicks in and actually sends signals to your jaw, lip and tongue muscles. Your mouth goes through some of the motions of speaking. This in turn feeds back into your brain -- the feeling of your mouth acting out speech routines triggers the auditory sensation of hearing your own voice. (When you actually speak, you almost always hear your own voice as a result, so your brain is just anticipating a well-trodden chain of events and playing your voice to you.)

I started thinking that your perception of your own identity could be tied in with the profound link between thinking and hearing your own voice, via the feeling in the mouth.

The evidence I have for this comes from the experience of my teeth moving when my wisdom teeth came through. I would be thinking, which would trigger the mouth-motions, which would feed back an inner voice. Because my teeth had moved, however, the tactile signals I got back from them weren't the ones I was used to, and the voice I "heard" was different as a result. It wasn't the inner voice I had come to associate with the idea of "me" over my whole life, but a modified version that I didn't identify with.

The modifications were very minor, but they happened to confer some characteristics of speech which for some reason my brain had broadly categorised as "annoying" and "goofy". To have an annoying, goofy version of myself played back in my head, every time I tried to have a thought, was really quite something; and it didn't stop there -- hearing the voice would in turn make me intensely aware of the parts of my mouth that had caused it, and so on, sending me into spirals of utter and all-consuming rage. I got into the habit of obsessively repeating thoughts, trying to get the voice right, and it was always hopeless -- the power of the brain to correctly anticipate the kind of sound that would have come out, had I spoken the thoughts, was impossible to overcome.

Eventually I just got used to the new shape of my mouth, but not without some hard mental work and a handful of "fits" as a result of the rage.

I'm not sure how much of a person's identity or sense of self is based on this connection between thinking and playing out muted speech routines with the mouth, but for me it seemed like quite a lot. I felt like I had lost something of myself when I couldn't create the familiar "me" voice, and when I couldn't just bite down and feel the familiar constant of the way my teeth fit together. Obviously I was still the same person, and an outsider wouldn't have been able to tell that anything had changed, but having felt first-hand what can happen when the teeth are dramatically reconfigured in a short space of time, I'm convinced that they play a more significant role in the whole thing than most people might appreciate.

Oh, and that part about “eventually just getting used to it”? Yeah, not quite – turns out it’s more like a cycle.