The Freeze Response
Maybe you have heard of fight and flight. These are two of our survival responses—when we are in trouble we might fight or we might try to get away. There is another survival response called freeze and it is pretty much what it sounds like. There are many situations in which fighting or fleeing won't work. Not only that, it might actually put a person in more danger. So thank goodness for freeze. We just shut down, don't do anything and wait for the danger to pass. Part of the freeze response is actually feeling less pain (quite handy if one has a significant injury or is being hurt).
As humans, we often have judgments about the freeze response, especially if it was our freeze response. It feels "weak" or passive, we might feel ashamed that we didn't do more. Other animals don't think about these things. Our biology only cares about surviving, so if we are still alive, then we were successful and all is well. It doesn't much matter how we got there.
The only real problem with freeze is that it is meant to be a short-term response. It really does shut down the physiology, so it causes problems if we spend lots of time there. For some of us, freeze becomes our default or is used when other responses might work better. This can be especially true for those who experienced childhood trauma where freeze is really the only way and can become well-established in infancy. It's not a choice someone is making as an individual, it is a learned habit of the nervous system. And it can be unlearned. Ideally, we would like to have access to all of our survival responses (including social engagement), so that our system responds in the most effective way in any situation.
In Somatic Experiencing, when working with someone with an overactive freeze response, we are looking to do two things. We want to increase access to other survival responses, such as fight and flight. And we want to "complete" the freeze response, which includes integrating the fact that it was successful, that it worked, that it's a good thing.