Test-Operate-Test-Exit, a feedback loop proposed as the basic unit of behaviour by the US psychologist George A(rmitage) Miller (born 1920) and co-authors in their book Plans for the Structure of Behavior (1960). This hypothetical mechanism responds to a stimulus (1) by testing it for incongruity, operates to remove the incongruity if any is found, tests again, and so on indefinitely until the incongruity is eliminated, then exits. The authors explained in a key passage that the TOTE is intended as a conceptual alternative to the reflex arc: ‘Obviously, the reflex arc is not the unit we should use as the element of behavior: the unit should be the feed-back loop itself. If we think of the Test-Operate-Test-Exit unit—for convenience, we shall call it a TOTE unit—as we do of the reflex arc, in purely anatomical terms, it may describe reflexes, but little else. That is to say, the reflex should be recognized as only one of many possible actualizations of the TOTE pattern’ (p. 27). It is not only energy that flows through the feedback loop, but also information and control, and it can be actualized at the cognitive level, as in the following example, especially apt for illustrating feedback: a person who is cooking tests a sauce for taste, notes an incongruity between the sensory input and the desired or expected taste, operates by adding various ingredients, tests again and repeats the cycle until no incongruity is found, then finally exits from the feedback loop.