ON ACTING: "Repetitive Rhythm"
It indicates the actor is controlling the performance with their head, their actor's brain acting as a control mechanism, a filter through which all natural variation of form and feeling (if there is any) blend into a constantly rhythmic release. Think of pouring a series of liquids through a filter: no matter how varied the diverse flows enter the filter, the resulting stream coming out steady, constant and monochromatic.
If the actor finds themselves in such a performing condition, the actor in their next run-through or film 'take' should 'kill the actor' in them, forget their previously 'planned' performance, and focus their entire attention on dealing with the other character in a goal seeking way. Seek to convince the 'other' character of the rightness of one's position, rather than worrying about the 'self' in acting.
Being other-focused rather than self-focused is the quickest was to achieve a desired state of natural emotional spontaneity and achieve the human variation that invariably results.