Framework 08, Siegel
Window of tolerance
There is a band where you can think and act. Above it is fury. Below it is nothing.
Daniel Siegel described a window of tolerance: the band of arousal within which a person can think clearly and act effectively. Above it is hyperarousal: racing, furious, flooded, unable to settle. Below it is hypoarousal: flat, numb, shut down, unable to start.
Stress narrows the window. After a major loss or change, it can be much narrower than usual, which is why small things set off rage on Tuesday and nothing at all gets done on Wednesday.
Why it matters
It is the most practical model on this list. It explains both the anger and the numbness with one picture, and it gives you something concrete to notice: am I above the window, inside it, or below it right now?
Either furious or nothing is a pattern with a name, and it is not a character flaw.
What it is not
It is a teaching model, not a diagnosis or a measurement. The practical steps that come with it, like getting outside, moving, eating, and slowing your breathing, are general and widely used. If you are stuck above or below the window most of the time for weeks, that is worth taking to a doctor.