Expectation is the capacity to anticipate certain events when a particular external stimulus is present. Anticipation is the capacity to foresee or predict

future events when there are no external stimuli directly or indirectly related to those events. Besides the temporal element, present versus future, these processes are in contrast in that expectation may involve physiological changes whereas anticipation is almost exclusively a mental phenomenon. Anticipation, which originates during the anal period and operates in the experience of anxiety, is a function of the frontal lobes.

Arieti edges up obliquely to the problem of the psychodynamics of time perception but never faces it directly. Incidentally, he is surprised by the clinical observation that neurotics think mainly of the past.