Rigidity of action is a natural consequence of excessive change, especially where no other adaptive response is possible. Not only do we see this with physical danger, but with more subtle threats as well. Wherever too much happens too fast, people grab for stability. They become conservative, not just in physical movement, but also in dress, language, religion, and politics. They seek stability and the illusion of stability.
Behavioral rigidity takes extreme forms.
The so-called authoritarian personality demonstrates what seem to be diametrically opposed behaviors. He ruthlessly dominates subordinates and thereby reduces threat from that quarter. At the same time, he is fawning and ingratiating with superiors, for he fears their displeasure. In both cases he buys time and reduces danger from people who are possible sources of risk. People overwhelmed by stress in their lives, seek security in the familiar, for that is what has been stable in their experience.