In 1894 the term “perseveration” was first used in psychiatry by Neisser to indicate abnormally persistent repetition of an activity after the activity should have been completed, such as is shown in the frequent speaking or writing of a word or words in unsuitable places. Thus originally the term was descriptive of a particular and circumscribed symptom to be recognized in the clinic. In 1900 the term was used in psychology by Müller to indicate the tendency which every idea has, after having once occurred, to remount spontaneously into consciousness.