Orne, M. T. On the nature of the posthypnotic suggestion. In L. Chertok (Ed.), Psychophysiological mechanisms of hypnosis. Berlin: Springer-Verlag, 1969. Pp.173-192.

On the Nature of the Posthypnotic Suggestion*


Institute of the Pennsylvania Hospital and University of Pennsylvania


Attempts to Define Hypnosis

A number of colleagues have discussed various aspects of hypnosis but, for the most part, we have tended to avoid defining operationally what we mean by hypnosis. Often we may not be aware that we have avoided doing so because of the comfortable knowledge that investigators, clinicians, and even laymen will manifest a high degree of consensus about what constitutes hypnosis. Certainly, when an individual agrees to be hypnotized and the hypnotist has carried out a hypnotic induction procedure and then demonstrated that the subject becomes essentially unresponsive to environmental stimuli other than the hypnotist's voice or appropriate suggestions--seems unable to open a clenched fist or bend a straightened arm, is able to sniff a bottle of ammonia with obvious expressions of delight because he has been told the odour was that of a rose, remains relaxed and comfortable despite the application of noxious stimuli, hallucinates objects that are not there while failing to see other objects which he has been told are absent, and, finally, having been told that subsequent to awakening he would nod if the hypnotist removes his glasses, awakens with no apparent recall for any of the events that have transpired yet nods, apparently without awareness of his behaviour, each time the hypnotist removes his glasses--we would all agree that the subject had been deeply hypnotized.

Much of the confusion about hypnosis stems from the fact that, while each of us has a clear picture of the classic somnambulistic subject, there is much less consensus about what constitutes an appropriate working, operational definition with which to carry out our research. The problem is in some ways analogous to the difficulties which for a long time centred

* This report was supported in part by grant number Nonr 4731 (00) from the Office of Naval Research.

I wish to thank F.J. Evans, C.H. Holland, J.J. Lynch, E.P. Nace, Emily Carota Orne, D.A. Paskewitz, and Joanne L. Withington for comments made during the preparation of this report.



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around the definition of sleep. Again, each of us could comfortably say sleep is that state which we enter each night. Consensus could easily be established when an individual was essentially unresponsive to outside stimuli, his breathing, heart rate, and other metabolic functions were somewhat slowed, his spontaneous activity greatly diminished, and, when aroused from this condition, would report having been asleep. These problems were simplified in some ways when EEG criteria for sleep were discovered. While these criteria were of great help, it was soon discovered that there were several different stages of sleep, and that the relationship between these stages was extremely complex. Not only would different measures of arousal, such as the electrodermal response and EEG criteria, relate in peculiar ways but, given clear physiological criteria of sleep, it seemed that these were not invariably associated with the behaviour which normally characterizes sleep. Natural somnambulism, where the individual may interact with his environment, occurs in what otherwise seems to be sleep's deepest physiological level--Stage 4. Studies in our laboratory, for instance, show that an individual during Stage 1 sleep is capable of carrying out apparently purposive behaviour in response to suggestions administered while he is asleep without any evidence of physiological arousal (Evans et al., 1966; 1970). In other words, the physiological criteria by which we now commonly define sleep allow us to recognize that it is possible for the individual to be in physiological sleep and yet show patterns of behaviour that we would have heretofore associated with the waking state. It is not intended here to review these fascinating apparent paradoxes emerging from current sleep research: I wish only to point out that, even when apparently clear-cut physiological correlates of a universally recognized state such as sleep become available, not all definitional problems are automatically resolved.

Unfortunately, in the study of hypnosis, we are in an even more difficult situation because no reliable physiological correlates have thus far been identified. Not only do we lack physiological correlates that are associated exclusively with hypnosis, we do not even have physiological correlates that are invariably associated with it. It may be hoped that reliable neurophysiological correlates can ultimately be developed. Until this is possible, it is necessary to utilize behavioural correlates. Traditionally, there are three ways in which hypnosis has been defined, both clinically and in research contexts: (1) By the presence of an induction procedure---hypnosis is the state which ensues after a trance induction procedure has been carried out; (2) by the behaviour of the subject--the subject is hypnotized if he responds to a set of test suggestions; and (3) by the experiential report of the subject---the subject is hypnotized if subsequently he reports that he had been hypnotized. When, as in the example which I gave earlier, all three of these bases for asserting that the subject is hypnotized are included,


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one can see why consensus about the presence of hypnosis would be so easy to achieve. Difficulty is encountered when different workers focus upon different aspects of the total situation as the reason for asserting that the subject was hypnotized. Each of these criteria has been used by different investigators and each way of defining hypnosis has certain advantages and disadvantages. Most important is the fact that very different empirical results will often be obtained, depending upon how hypnosis has been defined.

Traditionally, the clinician considers as hypnotized (thus ascribing any beneficial results to hypnosis) any patient with whom he has carried out a hypnotic induction procedure and who manifests a modicum of relaxation. Somewhat paradoxically, some of the recent studies carried out by radical behaviourists in the United States (see, for example, Barber, 1965) follow this identical model; that is, hypnosis is operationally defined by the fact that the experimenter has carried out a trance induction procedure, regardless of the subject's response. Thus, Barber always views hypnosis as an independent variable in his research. The difficulty with such a definition is that response to a hypnotic induction procedure follows a normal curve of distribution, which means that some individuals will manifest the two other defining characteristics of hypnosis (being able to respond to suggestions and reporting that they have been deeply hypnotized), other subjects will not be affected by the procedure at all, while the bulk of individuals will be affected in varying degrees. Since only some subjects will be hypnotized by the procedure in the sense of showing all the classical characteristics, any effect which would necessarily depend upon the totality of the phenomenon could easily be obscured in any experiment by the large number of subjects who are not responsive*.

Another way of defining hypnosis is by the subject's response to a series of test suggestions. This way of characterizing hypnosis has long been utilized. The Stanford Hypnotic Susceptibility Scale, Forms A, B, and C, developed by Professor Hilgard and his associates (Weitzenhoffer and Hilgard, 1959; 1962), are a series of carefully standardized tests of such suggestions with well established psychometric properties. Let me emphasize that it is the response of the subject to these test suggestions that determines whether or not he is considered hypnotized. This way of defining hypnosis seems far more appropriate as long as we keep in mind that the behaviour is meaningful only in so far as it truly reflects the subjective experience of the individual. When, for example, the suggestion is given in Stanford Hypnotic Susceptibility Scale, Form A, that there is a fly buzzing around the subject's face and it is troublesome, a facial flinch is scored as a positive response. To the extent that such a flinch reflects the

* For an excellent discussion of Barber’s work on this issue see Hilgard (1965).


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subject's experience of being troubled by a fly, it is an excellent measure of hypnosis; to the extent that the subject may feel pressured to behave in this fashion without actually experiencing the fly, it would represent an error of measurement *.

Finally, the extent to which the subject feels affected is the traditional clinical way in which hypnosis is often evaluated. Only relatively recently have investigators focused upon this attribute. The relationship between the extent to which a subject feels affected and his ability to respond to hypnotic suggestions is by no means perfect. Some subjects who, to the observer, seem deeply hypnotized are barely affected; others who are only minimally responsive to suggestions rate their experience as deep and seem profoundly moved. A great deal of work will be required to clarify the extent to which the subjective experience of having been hypnotized may play a role in determining hypnotic behaviour.

In our work we have felt it essential to define the presence of hypnosis on the basis of all three criteria, since only in this fashion can we be certain that we are dealing with the phenomenon that all of us would agree is hypnosis. Starting out in this fashion, it then becomes possible to ask: what aspects that are commonly associated with hypnosis require all three components to be present? It is certainly possible, even likely, that much that is attributed to hypnosis and would be associated with the classic phenomenon may require only one or another of the definitional attributes.

Posthypnotic Behaviour

I would like to report briefly a series of studies which attempt to clarify the nature of posthypnotic behaviour. We chose posthypnotic behaviour in this context because it is one of the behavioural phenomena that, to layman and professional alike, most clearly delineates hypnosis from other kinds of occurrences. Remarkably few studies dealing specifically with the mechanisms of posthypnotic suggestion have been carried out despite the fact that it characterizes the unique qualities of hypnosis.

A deeply hypnotized individual, instructed during hypnosis that at some later time he will carry out an item of behaviour in response to a specific cue, will tend to do so, often without awareness that he is carrying out a suggestion. In fact, posthypnotic suggestion has often been used as one of the demonstrations of unconscious motivation (e.g., Erickson’s

* I would like to avoid the almost metaphysical issues about the extent to which one can know subjective experience. It is intended here only to emphasize the reason why behaviour is a useful criterion because, under usual circumstances, it reflects what an individual experiences. This relationship can, however, readily be distorted by the kinds of instructions.


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demonstration of psychopathology in everyday life, 1947). Though it is well established that suitable individuals will carry out even bizarre posthypnotic suggestions, and Erickson has shown that, in some instances at least, such responses could be elicited even after a period of years by the hypnotist, it has not been shown to what extent the posthypnotic response depends upon the relationship between subject and hypnotist as opposed to the fact that the suggestion is given during hypnosis. Again, the importance of posthypnotic amnesia is by no means clear in this context. Damaser (1964), in our laboratory, carried out a study attempting to clarify several of these issues.

Kellogg (1929) and Patten (1930) had shown that a posthypnotic response may persist for a considerable period of time, but they had also found the somewhat surprising result that other subjects, not hypnotized, given the same instructions would carry out the suggestion for an indeterminate length of time without showing any diminution. These studies had not been controlled for such factors as depth of hypnosis or extent of relationship between subject and hypnotist, nor was there any evidence to show that they employed deeply hypnotized individuals; furthermore, the subject was required to come back to the laboratory each time to be tested by the hypnotist. We wished to know more about the persistence of posthypotic behaviour away from the hypnotist.

The first task was to design a measure which would yield data about a subject's performance over a long period of time without requiring him to come to the laboratory. It was decided to give subjects a stack of postcards with instructions to mail one to the laboratory daily. This technique did not require the subject to return to the laboratory but, none the less, provided a free operant response yielding an item of data for each day over a long period of time, actual data collection being carried out by courtesy of the post office. Before using this measure for the study of posthypnotic behaviour, it was felt essential to determine whether it was subject to laboratory manipulation. Accordingly a pilot study was carried out to test the effect of different instructions upon the postcard-sending behaviour over a period of time.

In brief, the question asked was: What was the effect of payment presented as simple monetary reward as opposed to the way the payment was perceived by the subject? Student volunteers were solicited by an announcement to participate in a particular psychological study. They were paid $2.50 to take a number of psychological tests lasting approximately 11/2 h. The subjects were divided randomly into four groups. The first group were told at the end of the experiment that they had done very well, but that it would be very helpful if, as a favour to the experimenter, they would agree to carry out a task which would take but a minute or two a day for the next couple of months. After they had agreed to do so, the


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experimenter gave them a stack of 60 self-addressed postcards and asked them to mail one to her every day, explaining that it was important that only one be mailed each day and that no two could be sent at the same time.

The second group, also at the completion of the testing, were asked exactly the same question as the first group and, after having agreed before knowing what the task was, they were given a similar stack of postcards and the same instructions. In addition, however, they were told that, at the completion of the study, they would be paid 10 cents for each postcard that was sent. Thus, in addition to the $ 2.50 which they were paid for taking the test, they could earn an additional $ 6.00 by sending the 60 postcards, a total of $ 8.50.

The third group were treated exactly as the first group, with the one exception that they were paid $ 8.50 for taking the test, thereby equating the amount of monetary reward that the second group could earn, but they were asked to send the postcards as a favour to the experimenter, exactly as the group that was paid only $ 2.50 for taking the test.

The final group was paid $ 2.50 for taking the test and, after they had agreed to do the experimenter a favour, the task was explained to them and they were also told that they would receive 10 cents for each postcard; that is, a total of $ 6.00 for sending the 60 postcards. However, in contrast to the other groups, they were then paid the $ 6.00 in advance after they had committed themselves to sending the postcards.

It was hypothesized that the last group, which had accepted the $ 6.00 as advance payment for a task that they had yet to do, would send the most postcards because, considering the amount of money involved, guilt would most likely be a stronger motivating force than the possible loss of 10 cents. The findings in this preliminary study came out in line with the hypothesis, supporting the contention that the meaning of monetary reward is of considerably greater significance than the actual amounts involved.

Having shown that postcard sending outside of the laboratory was subject to influence by psychological manipulation inside the laboratory, we utilized this procedure to study posthypnotic behaviour. In the experiment itself, three groups of subjects were compared. The first group was hypnotized, and during hypnosis given a posthypnotic suggestion that they would send a postcard each day. They were then given a stack of postcards, told to place them in their pockets *, and instructed to mail one every day. The subjects were then awakened and told the experiment was completed. No further mention was made of the postcards, and they were sent home with the postcards in their pockets.

* These postcards were "business reply cards", which means that they do not have stamps but do not require postage. This was to avoid putting undue pressure on the subject by giving him cards which had actual stamps on them and yet not requiring him to do anything beyond signing his name and mailing the card.


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The second group of subjects were deeply hypnotized, and given the same suggestion in an identical manner, except that they were not required to put the postcards in their pockets at that time. Instead, each subject was awakened and in the awake state it was explained to him that the experimenter wanted him to do something that was very important to her--to send a postcard each day. This group was then given the posthypnotic suggestion, and requested to carry out the same behaviour, in the waking state.

Finally, the last group was deeply hypnotized but not given any posthypnotic suggestion at all. Instead, upon awakening, they were given a stack of postcards and asked to send one every day. This group then had only the awake request.

The three groups were carefully equated for hypnotizability and the subjects were required to demonstrate all of the criteria of deep hypnosis, including amnesia for the period of one week. After the subject had been carefully tested several times and it was established that he was a good hypnotic subject, he would come for a long session during which he was hypnotized and given the suggestion of posthypnotic amnesia, which was not lifted. Returning to the laboratory one week later, he was interviewed by a research assistant about his experiences during the preceding week. This research assistant behaved as though she did not know what posthypnotic amnesia was and, after the subjects said they could not remember what had occurred while they were under hypnosis, they were urged to try because "it only happened last week; you must remember something about what occurred". It should be noted that only a very small percentage of subjects will maintain complete amnesia under these circumstances. More frequently they will recall one item of experience after another from the preceding session. We feel it is very important that this kind of test be carried out by someone other than the hypnotist, since many subjects report more complete amnesia in his presence.

In addition to this group of very deeply hypnotized individuals, another group of moderately hypnotizable individuals was also run, again subdivided into the three conditions outlined earlier.

The overall findings were somewhat surprising; namely, the groups which received the posthypnotic suggestion alone sent fewer postcards than those who received the request in the awake state. This result was in line with the observations of Kellogg (1929) and Patten (1930). The reasons for this finding became clearer when the experience was discussed with the subjects after the completion of the experiment. Subjects who were in the posthypnotic group correctly surmised that the purpose of the experiment was to determine how long a posthypnotic suggestion would last. Even in the very deeply hypnotized group they became aware of the fact that they were carrying out rather unusual behaviour in mailing a postcard each day to a post office box in Cambridge (U. S. A.), and figured


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out that this must be related to the experiment. The subjects then tended to send the postcards as long as they felt compelled to do so. When their compulsion to carry out the suggested behaviour waned slightly, they did not feel it appropriate to force themselves to continue to send the cards, since to do so seemed to them to be "cheating". They felt that they were being used to determine how long posthypnotic suggestion lasted and that they ought, therefore, to continue to send postcards only as long as really compelled to do so.

The subjects who were in the waking request group, on the other hand, saw the situation quite differently. They felt that it was very important for the success of the experiment that they continue to send postcards as long as possible, and many of them expressed concern that the nice young lady who was carrying out the experiment might not get her Ph.D. if they failed to send the postcards. It is clear that the subjects' attitudes toward their own behaviour differed greatly and, while it is true that the waking request was more effective in eliciting postcard-sending under these circumstances, we must not lose sight of the fact that the remarkable aspect of the posthypnotic suggestion is that the subjects did send a considerable number of postcards.

Of perhaps equal interest in this context is the implication of these data for the naive concept that posthypnotic suggestion can somehow be explained as simple cooperation with the experimenter on the part of the subject. Obviously, if this were the case, the subject responding to posthypnotic suggestion ought to send the same number of, or more, cards than subjects responding to waking requests to do so. That this is not the case strongly supports the view that we are dealing with a qualitatively different kind of phenomenon.

Before describing the next study on posthypnotic behaviour, a digression is necessary to describe one of the special methodological quasi-control procedures (Orne, 1962; 1969) used to evaluate the validity of experimental manipulations. Particularly in hypnosis research, we have used control subjects who are simulating hypnosis to a "blind" experimenter, in order to evaluate the extent to which the demand characteristics of the situation might be determining the results of the study. The special treatment group consisted of a group of subjects who had been tested repeatedly concerning their ability to enter hypnosis, and where it had been established that, despite good cooperation and several honest attempts on their part to be hypnotized, these individuals had been unable to do so with several hypnotists. Since the ability to enter hypnosis is remarkably stable, the probability of these individuals' subsequently being hypnotized was quite low. These subjects were then instructed as follows:

"During several experimental sessions you have tried to go into hypnosis and I realize that you have been unable to respond to hypnotic suggestions.


181 On the Nature of the Posthypnotic Suggestion

In this experiment your task will be quite different. As part of a special procedure, I want you to take part in this study and simulate being deeply hypnotized. In other words, your task will be to work with Dr. X and to convince him that you are in fact an excellent subject and that you have been deeply hypnotized by him. Dr. X knows that some subjects may try to simulate, but he does not know who, and he will obviously not have any idea that you are trying to fake being deeply hypnotized. If he catches on to the fact that you are simulating, he will stop the experiment immediately, so don't feel that you have given yourself away regardless of what you do, since Dr. X would stop the experiment if you had. Other subjects taking part in this experiment are individuals who have had repeated experiences with hypnosis so that they are able to enter deep trance readily, and it is your task to convince Dr. X that you too are an excellent subject. This holds true not only for the hypnotic session but also for any questions he might ask you about the session subsequently. Since the experiment involves two days, it applies until the experiment is completely over. Under no circumstances should you let on that you are simulating. Only when I see you again at the very end of the experiment will you tell me what really happened. Any questions or tests that are given to you during the experiment you are to answer as though you were deeply hypnotized or had been deeply hypnotized. I realize that you may be asked to do things where you might have no idea how a deeply hypnotized subject would respond. Don't let that worry you. Do the best you can. This is a difficult task, but we have found intelligent subjects able to carry it out successfully. Good luck!"

Simulating subjects given these instructions were randomly interspersed with subjects who were in fact able to enter deep hypnosis readily. For this kind of control group to work properly, it is crucial that the hypnotist in fact be blind as to which subjects are simulating. Extensive work in our laboratory has shown that simple observation, even by highly trained hypnotists, is not sufficient to discriminate between simulating and deeply hypnotized individuals, though special test procedures will allow such discrimination. The virtue of such a special treatment group is that it becomes possible to determine what aspects of the hypnotized subject's behaviour could be due to the average individual's prior knowledge about hypnosis, or explicit and implicit cues given by the hypnotist or inherent in the experimental procedure that may communicate what is expected of the subject (e.g., many aspects of the hypnotized individual's behaviour, such as appearing drowsy; speaking in a low monotone; moving in a somewhat retarded fashion; the ability to show remarkable strength as, for example, when told to be entirely rigid; the ability to support the weight of another individual upon one's abdomen while supported between two chairs; the ability to tolerate painful stimuli with little or no evidence of discomfort; etc., etc.). The fact that simulating subjects may successfully


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mimic the behaviour of deeply hypnotized individuals does not, of course, indicate that the process occurring in these two groups is the same; it merely demonstrates that hypnosis does not in these instances cause a transcendence of normal physiological capabilities, and that the experimental procedure has not been adequate to show a characteristic that is uniquely a function of the hypnotic phenomenon. This is particularly important, since many of the controversies about hypnotic phenomena appear to have been caused by very subtle differences in treatment procedures. The use of simulating subjects provides a relatively easy objective way in which the experimenter may determine those aspects of a subject's behaviour which could have been inadvertently induced by cues from him that might well have been outside of his own awareness*.

It should be emphasized that the failure to find differences between simulating and deeply hypnotized subjects does not mean that the process by which these behaviours are brought about is the same. This is analogous to asking an individual to simulate schizophrenia and comparing him with actual schizophrenic patients. If individuals are able to simulate schizophrenia, one would not conclude either that schizophrenia is therefore simulation, or that the simulator is schizophrenic. Rather, one would conclude that the diagnostic procedure is not adequate to eliminate the possibility of simulation, and one would hesitate to talk about certain behaviours that could only be ascribed to schizophrenics. Much in the same way, the failure to find differences between simulating and deeply hypnotized subjects in any given experiment merely indicates that the experiment is not conclusive, in that an alternative hypothesis may be entertained about the hypnotized subject's behaviour. This is particularly relevant when we are discussing the transcendence of normal volitional capacities or abilities. Simulating subjects have proven equally as important in physiological studies of hypnosis as in behavioural studies. For some reason, we tend to believe that a physiological response is somehow more "real" and less subject to interference by psychological parameters than the behavioural response. To our dismay, we have found that simulating subjects are often able to produce the same kind of physiological responses as deeply hypnotized individuals. (See, for example, Damaser, et al., 1963.)

Some Recent Studies of Posthypnotic Suggestion

An entirely different approach to an understanding of posthypnotic behaviour follows from the work of Seymour Fisher (1954). In an ingenious experiment Fisher suggested to deeply hypnotized subjects that, on

* The controversies between the Salpetriere and Nancy Schools are a classic example of the kind of issue which could have been resolved very quickly had simulating controls been available.


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awakening, each time they heard the word psychology they would scratch their right ear. After waking the subjects, he tested the suggestion by using the word, and was able to elicit the suggested behaviour. At this point, one of his associates came into the room and by innuendo the experiment was terminated. The associate, Dr. Fisher, and the subject entered into an informal conversation about current topics of the day. In the course of this informal conversation at the conclusion of the study, the word psychology came up spontaneously. Of the 12 subjects, only 3 responded during this time. After some minutes of conversation, the associate left and Fisher, turning back to his subjects, would by implication continue the experiment and would conspicuously use the word psychology in a sentence. Under these circumstances all of his subjects resumed responding by scratching their right ear. When asked about their behaviour during the preceding period, several of the subjects erroneously insisted that they had continued to respond, while others gave very transparent rationalizations. From this study, Fisher concluded that the posthypnotic response is a function of the subject's expectations of what is desired, and would be carried out only as long as he believed the experiment to be in progress.

In a recent study (Orne et al., 1968), we hypothesized that it was plausible that in the Fisher study subjects perceived the original suggestion to be that they ought to respond by scratching their right ear in response to the word psychology as long as the experiment continued, since the request to do so indefinitely would not be a plausible one. If this were actually the case, one would expect the subjects to stop responding when they believed the experiment to be over, and this finding would not necessarily have any implications for the persistence of a different kind of posthypnotic suggestion outside of the experimental situation. From our point of view, the Fisher study does not really test whether a subject who is given a clear-cut, time-limited posthypnotic suggestion will carry it out even under circumstances which he perceives to be outside of the experiment, where the hypnotist would be unlikely to know or even care whether the suggestion had been carried out. This question addresses itself to the issue of whether the posthypnotic response is a function of the suggestion given during hypnosis, or whether it is an attempt by the subject to please the hypnotist, depending, as it were, on the ongoing relationship.

An experiment was carefully designed which would require that the subject come to the laboratory on two succeeding days and take a number of personality tests, some while hypnotized. Subjects were informed in advance that they would be required to come on two successive days. The first day, in addition to taking a number of tests which were, in fact, part of another experiment, subjects were given the suggestion in deep hypnosis that for the next 48 h, each time they heard the word experiment, they would run their right hand through their hair. It should be noted that this


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suggestion was legitimized by the fact that subjects knew that they would see the hypnotist on the succeeding day. The suggestion itself, however, was clear-cut and explicit in placing a 48-h time limit on its effectiveness.

The next day, when the subject came to the laboratory the experimenter was informed by the receptionist of his arrival, and on meeting him in the waiting room and walking down the hall to the experimental room, the experimenter would carefully say, "I appreciate your coming back to the experiment”. This test, however, was not the crucial measure of the posthypnotic response.

Subjects taking part in our research are paid for their participation, and it is customary for them to return to the main office at the completion of a study where, after signing a receipt, they are reimbursed for their time. Each subject, on the completion of the first day's tests, returned to the secretary who asked him to sign the usual form, asking whether it would be all right to pay him "now for today's experiment and for the next part of the study tomorrow". The subject's response under these circumstances, in a different room totally outside the experimental context, constituted the first criterion test. On returning the subsequent day, the subject was met by the receptionist who asked whether he was participating in the physiological or the psychological experiment--two studies that were in progress at the same time. The subject's response to the receptionist constituted the second test.

The results showed that, using a highly selected group of subjects who were capable of entering deep hypnosis, subjects responded in the waiting room and the main office much as they had in the presence of the hypnotist. Thus, in some instances, since the word experiment was used quite casually, subjects did not always seem to hear the cue; on the other hand, the fact that the context was different, the experimenter was not present, and that the test was carried out in a way that appeared totally unrelated to the study, did not seem to interfere with the response. Interestingly enough, those subjects who responded most consistently were those individuals who also were most deeply hypnotized.

One of the methodological problems in this study was whether the test by the secretary was truly perceived to be outside of the experimental session. If, somehow, the way in which the study was carried out allowed subjects to suspect that the secretary was really recording their behaviour for the benefit of the hypnotist, the findings would have little relevance to the extent to which the posthypnotic response generalizes from one context to another. Obviously we would have much rather tested the posthypnotic suggestion totally away from the laboratory. Even if we had tested it in a classroom or dormitory, however, we would still need to ask whether the subject might not have suspected what we were doing. For this reason we ran a special treatment group of simulating subjects (de-


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scribed above), in order to ascertain how likely it might be that subjects could catch on to the fact that the secretary was really a subtle, but none the less crucial, part of the experimental procedure.

The simulating subjects allowed a hard test of the methodological problem of whether the receptionist was perceived as part of the experiment. In other studies we had noticed the not surprising fact that subjects who are asked to simulate hypnosis tend to be unusually suspicious. It is not surprising that a subject asked to deceive someone should be alert lest he be deceived himself. Therefore, the simulating subject provides a particularly rigorous test for the adequacy of the deception that was involved in our study when we made the crucial test of the posthypnotic response in the behaviour with the secretary and in the waiting room. Running both groups of subjects randomly intermixed and without knowing to which group any given individual belonged, we found that, of 17 deeply hypnotized subjects, 6 responded on both days, whereas of the 13 simulating subjects, not one subject responded on both days. These differences are particularly striking, since in the presence of the hypnotist the simulating subjects tended to respond more often, but in his absence the probability of their response was significantly less.

These data would seem to indicate that the posthypnotic suggestion is different in kind from the response to request. This finding is congruent with the observations of Kellogg (1929), Patten (1930), Edwards (1963), and Damaser (1964), all of whom found that the waking request is significantly more powerful in eliciting behaviour over a long period of time than the posthypnotic suggestion. Thus, we were particularly pleased to be able to demonstrate experimentally the kind of circumstances where the posthypnotic suggestion is more effective than a request--if we interpret the behaviour of the simulating subjects as responsive to a request. The deeply hypnotized subject appears to respond to a posthypnotic suggestion given in a way that communicates the intent that it should be carried out over a period of time--regardless of whether the hypnotist is present or whether the context demands a response. (See Orne et al., 1968; and Sheehan and Orne, 1968, for a further discussion of these issues.)

On a more anecdotal level, many examples can be cited which illustrate this characteristic of posthypnotic behaviour. It was dramatically demonstrated to us in the course of a pilot study. One of our subjects who had taken part in several studies with the laboratory, and with whom we enjoyed a good relationship, was able to enter extremely deep hypnosis. Because the subject was quite familiar with the laboratory, we felt his behaviour would not be comparable to that of more naive subjects, and therefore we tended to ask him to participate as a pilot subject in new studies.

In the context of seeking an experimental model to get at the unique characteristic of posthypnotic behaviour, I asked the subject, who was a


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biology student, to tell me the name of an animal that would be very unlikely to come up in the course of his work and about which he thought only rarely. He indicated the seal was such an animal. Since he was at the laboratory to take part in another study and would be back to take part in something else several weeks later, I gave him the suggestion when he was under deep hypnosis that, whenever he said or thought the word seal, he would run his right hand over his head. We were in the process of searching about for an appropriate suggestion and felt this one could be tested inconspicuously over a period of time. On returning to the laboratory some six weeks later, the subject spontaneously asked the experimenter with whom he was working at the time, at the conclusion of his particular study, whether perhaps he had been given a suggestion the last time he was at the laboratory, that could account for a peculiar red spot that appeared on his forehead. When the subject was directed to me (as is usual in unusual circumstances), I asked him about the quite noticeable red spot, and he first indicated puzzlement as to how it had gotten there; did he seem to understand how it might be related to any experiment--that it might somehow be connected. At that time, during the conversation, I tested the suggestion by bringing up the word seal, to which he responded by placing the palm of his hand on his forehead, over the discoloured area, while resting his hand on his head. He then said, "You know, it's a strange thing that you should bring up the seal, because I became very interested in this animal during the past six weeks. I read all the books the library has about the seal, and my wife and I discussed whether we couldn't get a pet seal to keep at home. I found out something about the cost and, while the seal wouldn't be that expensive, the cost of feeding him fish was pretty steep; also, he likes good facilities to swim, which we didn't have in our apartment." Indeed, our subject had become fascinated with seals and had literally read anything and everything available to him about this animal, expressing considerable dissatisfaction about the inadequacy of the library facilities in this respect! The red spot on his forehead turned out to be due to the heel of his hand resting upon his forehead as his fingers played with his hair while he was studying about the seal.

This somewhat dramatic and unexpected response, of course, constituted a considerable distortion of the original posthypnotic suggestion. Clearly, the sudden interest in the seal served a great many dynamic needs of the subject, and the posthypnotic suggestion only functioned as a trigger for the total behavioural pattern that it served. The suggestion was both brought into consciousness and removed, at which time the subject was able to understand much of what had happened. I felt somewhat disinclined to pursue this particular type of inquiry, since it seemed difficult to predict just how a long-term suggestion might be distorted and used to serve other needs. Certainly, the subject's response cannot be viewed as either role


187 On the Nature of the Posthypnotic Suggestion

playing or simple compliance; on the contrary, it seemed to be in the service of intrapsychic needs. It was particularly satisfying when it became possible to show in a more rigorous fashion the peculiar quality of the posthypnotic suggestion to transcend the context in which it is originally given.

A recent experiment carried out by Dr. Nace and me* explored what might happen to posthypnotic suggestions that are not carried out. This study also is related to an anecdote told by Dr. Robert White**. In the course of giving a lecture many years ago, he demonstrated hypnosis with a student volunteer who was told during trance that, prior to leaving the lecture room, he would place a chair upon the desk in the front of the room. The subject was awakened and the lecture proceeded. At the end of the hour the subject left, together with his colleagues, without carrying out the posthypnotic suggestion. That afternoon, while working in his office, Dr. White became aware of a noise in the corridor and, on investigating, Dr. White noticed the student who had been hypnotized that morning quietly entering the now deserted lecture room, picking up a chair, placing it on the desk at the front of the room, and leaving as quietly as he had come. It seemed likely that, while the response to posthypnotic suggestion was usually seen as an all-or-nothing matter, there must be instances when there is a considerable impulse to carry out the posthypnotic suggestion but various inhibitory impulses prevent the execution of the action. For example, in the case of Dr. White’s student, there would have been considerable embarrassment had the student felt impelled to undertake an action which made little sense to him and was unusually conspicuous. On the other hand, later on he sought out the opportunity to carry out the behaviour, again to satisfy something within himself rather than something between himself and Dr. White.

An experiment was designed which would try to grasp this type of phenomenon. Accordingly, subjects were hypnotized at three different times by two different investigators, using the Stanford Hypnotic Susceptibility Scales. During the third session when the subject was administered the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C), the posthypnotic suggestion was given that on awakening, when the hypnotist removed his glasses, the subject would feel compelled to pick up the blue pencil from a pencil box on the desk and play with it.

The very good hypnotic subject would, of course, respond to this posthypnotic suggestion. We reasoned, however, that there would of necessity be subjects where the impulse to carry out the posthypnotic suggestion would not be sufficient to lead to the actual behaviour, and now sought to create a situation where the subject, in order to fill out a questionnaire,

* NACE, E. P., and M. T. ORNE: The fate of an uncompleted posthypnotic suggestion. J. abnorm. soc. Psychol. (in the press) (1970).

** Personal communication.


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would require a writing implement and where he could, without necessarily even being aware of it, choose to use the blue pencil rather than one of the several other pencils present in the box. In other words, a situation was created where an action which had been suggested and had not been carried out posthypnotically could now be carried out in the context of doing something quite different.

Accordingly, at the completion of SHSS:C, the hypnotist took off his glasses and, after talking with the subject some moments more and making certain the subject was awake, indicated that there would be just one more questionnaire to fill out and, asking him to sit at a desk where he himself was at the moment, indicated that he was to complete the final questionnaire*. The hypnotist then indicated that he would return and, as soon as the subject sat down in the chair, turned and left the room. The subject was now alone in the room and could use any one of the writing implements in the pencil box, or a pen or pencil that he might have had with him. We predicted that subjects who chose to use the blue pencil under these circumstances would, in their response to hypnotic suggestion, fall between those individuals who had originally carried out the posthypnotic behaviour and those individuals who neither carried out the posthypnotic suggestion nor chose a blue pencil. In other words, we expected to be able to show that the choice of a blue pencil while filling out a questionnaire subsequent to hypnosis would be lawfully related to the other tests of hypnotizability which were carried out earlier both during the same session and during previous sessions, and that the use of the blue pencil under these circumstances constituted a response similar to that of carrying out the posthypnotic suggestion on cue, but that it would require less hypnotic depth to achieve it.

We, of course, took precautions to have pencil wells with a standardized number of pencils and colours throughout the laboratory, in order both to make certain that subjects would not see these as something special for the experiment on the one hand, and to obtain reliable base lines of pencil choices over a period of time. The occasional subject who showed a preference for blue pencils prior to the posthypnotic suggestion was excluded from the study.

We found that the mean hypnotizability scores (as measured by SHSS:C prior to the suggestion) of subjects who followed the posthypnotic suggestion was 8.5, of those who did not originally follow the posthypnotic suggestion but subsequently chose the blue pencil was 7.1, and of those subjects who were apparently unaffected by the posthypnotic suggestion was 5.9. The same relationship could be shown to hold for the hypnotiza-

* Subjects had filled out a number of questionnaires in the course of this study and this request was completely in line with what had previously been asked of these subjects.


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bility of these subjects when measured by the Stanford Hypnotic Susceptibility Scale, Form A, initially administered by the same experimenter, and by Form B given by a different experimenter.

It would seem, then, that a posthypnotic suggestion which is not carried out may none the less lead to an action tendency which, given suitable opportunity to do so, will be discharged. This may take place even though the hypnotist is not present and might have no way of knowing whether the suggestion was carried out.

We have discussed posthypnotic behaviour in experimental subjects. All of the former experiments requested items of behaviour which had little or no dynamic significance to the subject. They were selected to be essentially neutral. We tried to show that a posthypnotic suggestion in an experimental context is generally less effective in eliciting behaviour over a long period of time than a simple request to carry out the action; at the same time, that the posthypnotic response is not limited to the experimental setting but appears to generalize to other settings; and, finally, that execution of the posthypnotic response seems, in some subjects at least, to serve intrapsychic needs and results in a tendency toward closure that is independent of whether the hypnotist is aware of the response. It seems that the likelihood that a subject will carry out a posthypnotic suggestion of this kind is closely related to the depth of hypnosis that is achieved, measured by responsiveness to other test suggestions

Posthypnotic Behaviour in Clinical Situations

In the light of our discussion thus far, it is relevant to relate the response to posthypnotic suggestions given in an experimental context to the clinical setting. It is worth observing that here we are asking a patient to carry out behaviours that others have previously requested and which he has not been able to carry out; for example, giving up smoking, asking a conversion hysteric with a paralyzed right arm to lift it, etc. This would seem in striking contrast to the experimental situation, where a simple request seems more effective. Yet it has never been empirically tested, whether patients asked to carry out behaviour such as taking a noxious pill might do so in response to a simple request by a physician for a longer period of time than if they were told to do so by posthypnotic suggestion. The difference is that we are usually dealing with a task that, for one reason or another, the patient seems unable to carry out.

An interesting finding is that, in the therapeutic context, the likelihood of a patient's responding to a therapeutic posthypnotic suggestion seems almost uncorrelated with the depth of hypnosis that is attained. This observation has been made by many therapists and is certainly substantiated


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in my own practice. Not only are there many instances of patients who, although deeply hypnotized, have failed to respond, or responded only transiently to a therapeutic suggestion; but, in striking contrast, there are those instances of patients who apparently were unable to respond to any hypnotic suggestion other than relaxation, but who showed dramatic alterations in behaviour following a therapeutic suggestion*. It seems likely that the mechanism by which therapeutic suggestions become effective is only partially related to the mechanisms by which basically trivial posthypnotic suggestions are activated.

In order to make any statement about it, it is essential to be clear about what we consider hypnosis to be. As long as we consider everything to be hypnosis that occurs once a trance induction procedure has been carried out, it is not possible to determine which are the dynamic considerations. As soon as we more rigorously define hypnosis as the ability to respond to a series of graded hypnotic suggestions, however, it becomes possible to do so. In an experimental setting, London and Fuhrer (1961) and Rosenhan and London (1963), have abundantly demonstrated that hypnotic procedures may have a striking effect even on those individuals who do not enter hypnosis; that is, even though subjects were totally unable to experience any of the striking alterations in subjective experience that, in my view, define hypnosis, they nevertheless showed an increase in physical capacity and perseverance following hypnotic suggestions. It seems plausible that many of the dramatic and effective changes in patients following posthypnotic suggestions do not depend upon the patient's entering the state of hypnosis, but rather are a function of expectation and, perhaps, other subtle changes in their environment associated with the suggestions that have been given.

The recognition that the success of therapeutic suggestions may depend upon a wide variety of dynamic considerations, rather than the presence of deep hypnosis of the sort that is consensually recognized by everyone, may help to clarify some of the confusion concerning the nature of the posthypnotic suggestion. Giving a posthypnotic suggestion in a clinical setting involves communicating clearly to a patient what is desired of him by a therapist who is perceived as extremely powerful, if not magical, whose words may have considerable impact not only on the patient but on those close to him. Inevitably such a situation indirectly brings about changes which have little or nothing to do with whether the individual actually

*It must be emphasized, of course, that it is essential for the therapist to communicate to the patient that he has done well in hypnosis and that he expects the patient to respond to the therapeutic suggestion. Undoubtedly the expression of disappointment on the part of the therapist would tend greatly to diminish the likelihood of such a therapeutic response. It is perhaps because of the recognition that hypnotic depth does not matter, or the fear of communicating disappointment to the patient, that many therapists are disinclined to evaluate hypnotic depth.


191 On the Nature of the Posthypnotic Suggestion

enters hypnosis. It seems worthwhile to consider the possibility that there may be non-specific effects of hypnosis which do not require that the subject experience any of the changes of hypnosis except that he believe himself to have been hypnotized, much in the same way as a placebo response may occur after taking a "drug". In a recent study (McGlashan et al., 1969) we have tried to show how there are both specific and non-specific effects of hypnotic suggestions of analgesia and that these effects are in fact additive.


In this discussion I have tried to emphasize the extent to which the way in which we define hypnosis may determine the kind of observations we make. While I feel that a particular way of looking at the phenomenon may be especially fruitful, it seems much more important that we understand clearly how each of us looks upon it. Many of the difficulties in communication arise from our looking in different ways at different things which are called by the same name. Perhaps with more careful attention to details of definition and the precise circumstances of observation we may be able to clarify the kind of controversies that traditionally have been associated with the study of hypnosis.



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London, P., and M. Fuhrer: Hypnosis, motivation and performance. J. Personality 29, 321-333 (1961).

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Rosenhan, D., and P. London: Hypnosis: Expectation, susceptibility, and performance. J. abnorm. soc. Psychol. 66, 77-81 (1963).

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Weitzenhoffer, A. M., and E. R. Hilgard: Stanford Hypnotic Susceptibility Scale, Forms A and B. Palo Alto, Calif.: Consulting Psychologists Press 1959.

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The preceding paper is a reproduction of the following book chapter (Orne, M. T. On the nature of the posthypnotic suggestion. In L. Chertok (Ed.), Psychophysiological mechanisms of hypnosis. Berlin: Springer-Verlag, 1969. Pp.173-192.). It is reproduced here with the kind permission of Springer-Verlag.