Despite the general familiarity of posthypnotic behavior and its extensive role in both experimental and therapeutic work, little recognition has been given to it as a problem complete in itself. Instead, attention has been focused almost exclusively upon the various activities suggested to the subjects as posthypnotic tasks, with little heed given to the nature of the behavior characterizing, if not constituting, the posthypnotic state, and which influences and perhaps determines the nature and extent of the suggested posthypnotic performance.

Emphasis has been placed primarily upon the results obtained from posthypnotic suggestions and not upon the character or nature of the psychological setting in which they were secured. The study of the mental processes and the patterns of behavior upon which those results are based and which must necessarily be in effect in some manner previous to, if not also during, the posthypnotic performance, has been neglected. Yet despite a lack of adequate experimental provision there has been a general recognition of certain significant facts regarding the posthypnotic performance which imply directly the existence of a special mental state or condition constituting the background out of which the posthypnotic act derives.

Foremost among these facts is the occurrence of the posthypnotic act in response to a suggestion which is remote from the situation in which it has its effect. Next the immediate stimulus, posthypnotic signal, or cue eliciting the posthypnotic act serves only to establish the time for the activity and not the kind of behavior, since this is determined by other factors.

Also the posthypnotic act is not consciously motivated but derives out of a remote situation of which the subject is not consciously aware. Finally it is not an integrated part of the behavior of the total situation in which it occurs, but is actually disruptive of the conscious stream of activity, with which it may be entirely at variance. In a search of the literature published during the past 20 years, covering approximately 450 titles, no references were found which were suggestive of a direct study of posthypnotic behavior itself, although many of the titles indicated that posthypnotic suggestion had been used to study other patterns of behavior. Similarly a review of approximately 150 selected articles and books, some of which were published as early as 1888, yielded only a little information definitive of posthypnotic behavior as a specific phenomenon.

The more instructive references were found chiefly in the general textbooks on hypnotism rather than in experimental studies involving the use of posthypnotic behavior. However, even these were general assertions or brief, vague, and sometimes selfcontradictory statements, based either upon the author's own experience and that of others, or upon experimental material of an inadequate and often irrelevant character in which there was a marked confusion of the results of suggested posthypnotic activities with the mental processes and patterns of posthypnotic behavior by which those results were obtained.