Interfaces are not only read in space. They are also read in time. Every reveal, delay, transition, and response creates a rhythm that either supports understanding or adds noise.
Cognitive rhythm is the feeling that an interface is keeping pace with a person's attention. Motion can show cause and effect, mark priority, and help users anticipate what has changed.
The design challenge is restraint. Motion should not compete with content. It should shape sequence, confirm decisions, and give the eye a clear path through complexity.