Just now I’m sitting alone at my computer, reading this horrible story, and my unconscious reaction was that my jaw dropped. Actually it didn’t passively drop, it opened widely. My state of mind was “why the fuck would someone do such an awful thing?” Then I found myself wondering what physiological reason might be responsible for the jaw-dropping thing. It seems like an odd response to shock. It couldn’t have been to display my emotion to someone else, as there was nobody else in the room. Any thoughts?
Earlier today, alone in my car, I heard on the radio a graphic description of a boy being hacked to death in Liberia, and I think my jaw dropped. Physiologically, it felt a little like gasping for breath, or getting ready to hurl. I had to turn the radio off.
Phsyiologically, my WAG is, the surpise/shock/bewilderment reaction is so strong that all facial muscles suddenly and simultaneously relax.
The only time my jaw physically dropped of its own accord (as opposed to me faking it for effect) was on September 11th 2001, in my car, as I listened to the field reporter scream and cry as she reported the first tower falling and crumbling. I became aware of a dryness in my mouth and realized it had fallen open. My jaw stayed dropped the rest of that day.
I don’t think it’s a matter of the jaw muscles simply going slack, but rather an active primate anxiety display. Rhesus monkeys convey alarm or nervousness with a gaping mouth and raised eyebrows-- not baring their teeth aggressively (that comes later), but just opening their mouths wide in a sort of “goodness gracious me!” expression. I expect that the “jaw-dropping” reflex is the human analogue of such a display.
I expect it’s as cultural as anything. Things that seem automatic usually aren’t–for instance, the reaction to pain would seem to be universal, but we say “ow” to fire and the Japanese just as reflexively say itai! (I think that’s the spelling).
Yes and no. To a small pain or one that you have time to process words for then, yes, “Ouch” or “Itai” but if it’s a big shock of a pain then its just a yell for all of us.
And Japanese jaws drop in shock too, if that’s any help!
As I said though, it isn’t just relaxation (at least for me). I suddenly noticed that I was actively opening my mouth.