I'm not quite sure about where to post this. But we'll start with here. According to what I read, the "freezing" response (i.e., reacting by becoming immobile) in reaction to a threat is common among not only mammals but almost all vertebrates. The technical term for "freezing" in that sense is, I've learned, "tonic immobility."

When the "fight or flight" dichotomy was first proposed back in the 1920's, for various reasons the researchers involved did not include "freezing." A more accurate phrase would have been "fight, flight or freeze." The "freeze" reaction is, essentially, to play dead, to try to fool a predator by not reacting at all.

Among humans, it appears that "freezing" (tonic immobility) is as frequent a response as it is among other animals. But it hasn't received the attention it deserves until very recently. I haven't been all that successful in web searching for relevant articles. I'd most appreciate hearing from any of you folk who may have for whatever reason either studied or heard about or experienced anything in connection with this "tonic immobility" reaction. Take care!