Posthypnotic Amnesia Suggestion Research Articles

Doing better by getting worse: posthypnotic amnesia improves random number generation.

Although forgetting is often regarded as a deficit that we need to control to optimize cognitive functioning, it can have beneficial effects in a number of contexts. We examined whether disrupting memory for previous numerical responses would attenuate repetition avoidance (the tendency to avoid repeating the same number) during random number generation and thereby improve the randomness of responses. Low suggestible and low dissociative and high dissociative highly suggestible individuals completed a random number generation task in a control condition, following a posthypnotic amnesia suggestion to forget previous numerical responses, and in a second control condition following the cancellation of the suggestion. High dissociative highly suggestible participants displayed a selective increase in repetitions during posthypnotic amnesia, with equivalent repetition frequency to a random system, whereas the other two groups exhibited repetition avoidance across conditions. Our results demonstrate that temporarily disrupting memory for previous numerical responses improves random number generation.

A hypnotic paradigm for studying intrusive memories

Despite the importance of intrusive memories in clinical disorders, research has been limited by a dearth of paradigms that permit experimental study of intrusions. This study describes a hypnotic paradigm for eliciting intrusive memories. Forty-nine highly hypnotisable participants nominated a distressing memory prior to being hypnotised. During hypnosis, they received the suggestion that they would remember the memory in response to a designated cue after the hypnosis session. Half of the participants also received a posthypnotic amnesia suggestion for the source of the memory. Following hypnosis, all participants completed a cognitive task and during the task received the cue to recall the memory. Results demonstrated that memories experienced after posthypnotic amnesia were experienced as more involuntary and more distressing than those that were knowingly retrieved. Participants in the posthypnotic amnesia condition also demonstrated greater interference on the cognitive task after the retrieval cue was given than those who intentionally retrieved the memory. These findings suggest that posthypnotic suggestion provides a useful paradigm to elicit intrusive memories under experimental conditions.

Déjà Vu in the Laboratory: A Behavioral and Experiential Comparison of Posthypnotic Amnesia and Posthypnotic Familiarity

This experiment aimed to create a laboratory analogue of déjà vu. During hypnosis, 1 group of high hypnotizables completed a puzzle game and then received a posthypnotic amnesia suggestion to forget the game (PHA condition). Another group of highs were not given the game but received a posthypnotic familiarity suggestion that it would feel familiar (PHF condition). After hypnosis, all participants were given the game and described their reactions to it. Whereas 83% of participants in both conditions passed their respective suggestions, more in the PHF condition felt a sense of déjà vu. An EAT inquiry revealed that they experienced sensory fascination and confusion about the source of familiarity, akin to everyday déjà vu. These findings highlight the value of using hypnosis as a laboratory analogue of déjà vu and provide a framework for investigating clinical manifestations of this phenomenon.

Posthypnotic Amnesia For Autobiographical Episodes: Influencing Memory Accessibility and Quality

The authors examined the impact of posthypnotic amnesia on the accessibility and quality of personal memories. High, medium, and low hypnotizable individuals recalled two autobiographical episodes and rated those memories. During hypnosis, subjects were given a posthypnotic amnesia suggestion that targeted one of the episodes. After hypnosis, they recalled and rated their memories of the episodes. The posthypnotic amnesia suggestion influenced the accessibility and quality of autobiographical memory for high and some medium, but not low, hypnotizable participants. The article discusses these findings in terms of investigating and understanding the impact of posthypnotic amnesia on autobiographical memory.

Posthypnotic amnesia for a first romantic relationship: Forgetting the entire relationship versus forgetting selected events

This experiment investigated the impact of suggestion focus on posthypnotic amnesia (PHA) for memories of a first romantic relationship. During hypnosis, high and low hypnotisable participants recalled specific memories from this period in response to 10 cue phrases (Elicitation). They then received a PHA suggestion that targeted either the entire period or specific memories from that period. Participants' explicit memory was indexed by cued recall after PHA was administered (memories recalled to “old” and “new” cues; Recall 1) and after it was cancelled (Recall 2). A social judgement task indexed dissociations between implicit and explicit memory. PHA had the greatest impact on highs', but not lows', memory performance (in terms of memories recalled to old cues, recall latency, and qualitative memory ratings) when the suggestion targeted the entire period rather than specific events. We discuss these findings in terms of the parameters of PHA's influence on memory, its value for exploring the nature and structure of autobiographical memory, and its utility as a laboratory analogue of functional amnesia.

Posthypnotic Amnesia for Autobiographical Episodes: A Laboratory Model of Functional Amnesia?

Extreme variation in the accessibility of autobiographical memory is a major characteristic of functional amnesia. On the basis of its ability to temporarily disrupt the retrieval of memory material, posthypnotic amnesia (PHA) has been proposed as a laboratory analogue of such amnesia. However, most PHA research has focused on relatively simple, nonpersonal information learned during hypnosis. This experiment extended PHA to autobiographical memory by examining high- and low-hypnotizable subjects' explicit and implicit memory of two autobiographical episodes, one of which was targeted by a PHA suggestion. The effects of PHA were consistent with the major features of functional amnesia: PHA disrupted retrieval of autobiographical information, produced a dissociation between implicit and explicit memory, and was reversible. The nature of PHA's effect on autobiographical memory and the potential utility of a PHA paradigm for investigating functional amnesia are discussed.

Posthypnotic amnesia for material learned before or during hypnosis: Explicit and implicit memory effects

This article focuses on dissociations between explicit and implicit expressions of memory during posthypnotic amnesia (PHA). Despite evidence of such dissociations, experimental design in this area has not always been consistent with contemporary memory research. Within a paradigm that aimed for conceptual and methodological clarity, we presented 40 high and 38 low hypnotizable individuals with a word list either before or during hypnosis, gave them a PHA suggestion for the word list, and tested them on explicit and implicit memory tasks. In the absence of conscious recollection, highs showed equivalent levels of priming (perceptual and semantic) to lows. However, when analysis focused only on those highs who remained amnesic after the implicit memory tasks, we confirmed perceptual, but not semantic, priming. These findings highlight the impact of methodological choices on theoretical interpretations of memory performance following a suggestion for PHA.

Posthypnotic suggestion, response complexity, and amnesia

Thirty-eight high hypnotisable participants were given a suggestion for either a simple or a complex posthypnotic response. The suggestion was given either with or without an accompanying suggestion for posthypnotic amnesia. The type of suggestion had an impact on responding: 94% of participants given the simple suggestion and 16% given the complex suggestion responded. The accompanying presence of amnesia did not have an impact on responding: 46% of participants with amnesia and 63% without responded; 58% of those who did not receive the amnesia suggestion responded. The findings are discussed in terms of a model that highlights the interaction of internal and external processes that encourages or discourages posthypnotic responding.

Posthypnotic amnesia for material learned before hypnosis

The impact of a suggestion for posthypnotic amnesia on material learned either before or during hypnosis was investigated across 2 experiments. In Experiment 1, very high, high, and low hypnotizable participants learned a word list either before or immediately after a hypnotic induction. During hypnosis, participants were given a suggestion for posthypnotic amnesia for the word list. After hypnosis, they were tested on recall, word-fragment, and word-recognition tasks. Experiment 2 replicated and extended Experiment 1 through application of the real-simulating paradigm. Across the 2 experiments, there was no difference in the performance of participants who learned the word list either before or during hypnosis. Although amnesia on direct memory measures was associated with high hypnotizability (Experiment 1), an explanation based on demand characteristics could not be excluded (Experiment 2). The implications of these findings for the use of posthypnotic amnesia as a laboratory analog of disorders of autobiographical memory are discussed.

Posthypnotic Amnesia, The Hidden Observer Effect, and Duality During Hypnotic Age Regression

Abstract The present study sought to explore potential response differences to a suggestion for posthypnotic amnesia between those high hypnotizable Ss who do and those who do not manifest the hidden observer effect. In line with the hypothesis that Ss who responded to the hidden observer suggestion are more highly engaged in cognitive monitoring of their experience and behavior (Nogrady, McConkey, Laurence, & Perry, 1983), it was predicted that these Ss would recall more Stanford Hypnotic Susceptibility Scale, Form C (Weitzenhoffer & Hilgard, 1962) hypnotic items, and in greater detail, following the reversal of amnesia than would their no-hidden observer counterparts. In this regard, both the quantity and the quality of posthypnotic recall was examined in 15 high, 11 high-medium, and 11 low hypnotizable Ss. Data on posthypnotic recall from low and high-medium hypnotizable Ss revealed the comparability of the present sample to samples of other studies that have investigated posthypnotic recall using standardized hypnotizability scales. Contrary to prediction, hidden observer Ss recalled significantly fewer hypnotic items and in less detail. Similar results were found when high hypnotizable Ss were dichotomized with respect to the presence or absence of duality in age regression (Perry & Walsh, 1978). Results are discussed in terms of implications for future research.

Variables affecting subjective organization during posthypnotic amnesia

Subjects learned a list of unrelated words to a criterion of either two successive correct trials (standard criterion), or two successive correct trials plus five additional recall trials (extra criterion). The extra recall trials significantly increased the subjective organization of recall. In the extra criterion group, a posthypnotic amnesia suggestion and a nonhypnotic distraction task produced equivalent decrements both in the amount recalled and in the subjective organization of recall. In the standard criterion group, suggestion and distraction reduced the amount recalled, but not the subjective organization of recall. The implications of these findings for understanding the contradictory results of earlier studies of recall organization during amnesia are discussed. Implications for theories of hypnotic amnesia are also discussed.

Relation of predicted to actual hypnotic responsiveness, with special reference to posthypnotic amnesia.

Abstract Prior to receiving the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor & E. Orne (1962), 423 naive volunteer Ss were asked to predict their behavioral response to each of the 12 constituent HCSHS: A suggestions. Another 418 Ss made no prior predictions. The relationships between predicted and actual hypnotic responsiveness were significant for HGSHS:A as a whole (r = .34) and for many of the individual items (though all r < .22). Ss who received prior information concerning the contents of HGSHS:A scored significantly lower than those Ss who were uninformed. This difference was apparent for 9 of the 12 individual HGSHS:A items (all p < .Ol), although it was most apparent for the posthypnotic amnesia suggestion. Although Ss' expectations are significant determinants of hypnotic responsiveness, there is also considerable surprise and disappointment on their part. Implications of the results for the distinction between aptitude and attitude contributions to hypnotic responsi...

Optimal scoring of amnesia on the Harvard Group Scale of Hypnotic Susceptibility, Form A.

Abstract Response to the suggestion for posthypnotic amnesia on the Harvard Group Scale of Hypnotic Susceptibility, Form A (Shor & E. Orne, 1962) was studied in a sample of 1351 Ss. Reversibility proved to be a somewhat better criterion of response than initial amnesia, as indexed by both item difficulty and item-to-total correlations. Continuous scoring of recall, however, was no better than dichotomous scoring. A joint dichotomous criterion, consisting of recall = s 3 on the initial amnesia test followed by recall 2 2 additional items on the reversibility test, is offered as both empirically defensible and conceptually preferable.

Episodic and semantic memory in posthypnotic amnesia: A reevaluation.

Recently, Kihlstrom found that a suggestion for posthypnotic amnesia produced impairments on episodic but not semantic memory tasks. During amnesia testing, highly and very highly susceptible subjects showed reduced recall for a previously learned word list but no deficits on a word association task designed to elicit the forgotten words as associates. He hypnotized that posthypnotic amnesia involved a dissociation between episodic and semantic components of memory. We tested the alternative hypothesis that Kihlstrom's findings resulted from experimental demands conveyed by the wording of the amnesia suggestion he employed. We found that subjects could be induced to show only episodic impairments (thereby replicating Kihlstrom) or both episodic and semantic impairments (contrary to Kihlstrom) by subtly varying the wording of amnesia suggestions. These findings are inconsistent with a dissociation hypothesis. Instead, they support the notion that hypnotic amnesia is a strategic enactment strongly influenced by expectations generated in the amnesia testing situation.

Post-hypnotic amnesia: seeing is not remembering.

Prior to the administration of the reversibility cue to cancel a suggestion for post-hypnotic amnesia, subjects were exposed to a videotape playback of the events of the hypnotic session in the presence of an independent experimenter. The specific application of this method (the Experiential Analysis Technique) was designed to maximally cue subjects to recall and report on amnesic events. Performance of highly susceptible subjects who viewed the videotape indicated that amnesic subjects commented on fewer items, stopped the videotape less, and verbalized less than did non-amnesic subjects. The cued recall of the amnesic group was also often item-specific rather than general, and allowed one to distinguish between the impact of behavioural and experiential events. For some subjects, amnesia clearly could not be completely broken by the presentation of maximal cueing.