An event-related potential investigation of posthypnotic recognition amnesia.

Forty-two individuals selected for high hypnotizability or for low hypnotizability were taught lists of words during hypnosis and assessed for recognition following hypnosis using event-related potential (ERP) procedures, both before and after the cue to reverse amnesia. A subgroup of low-hypnotizable participants were asked to simulate hypnotic behavior. All participants had larger late positive component (LPC) amplitudes to learned than to unlearned words, regardless of whether amnesia was reported. The highly hypnotizable participants who reported recognition amnesia, however, had significant changes in attention-related (P1 and N1) and recognition-related (N400 and LPC) ERP component amplitudes as a function of whether amnesia was reported. These data suggest that posthypnotic amnesia may involve alterations in the processes of attention, selection, and accessibility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal organization of recall during posthypnotic amnesia.

Amnesia suggestions were administered to 35 undergraduates of low, medium, and high hypnotic susceptibility (the Stanford Scale of Hypnotic Susceptibility—Form C) who had learned a word list while hypnotized. The method encouraged Ss to organize the words sequentially. Organization of recall was measured on recall trials conducted before, during, and after suggested amnesia. Highly hypnotizable Ss showed a breakdown in temporal organization during amnesia, followed by a recovery of this organization after the suggestion was canceled. Results suggest that posthypnotic amnesia involves a disruption in the contextual relationships among memory items. Findings are discussed in the context of models that construe memory as a network of modes representing concepts and associative links between them. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal sequencing during posthypnotic amnesia: A methodological critique.

In studies by F. J. Evans and J. F. Kihlstrom, (1973, 1975, 1979), using the susceptibility-scale paradigm, high susceptibles (HSs) were less likely than low susceptibles (LSs) to recall the events of the hypnotic session in temporal sequence (i.e., temporal disorganization effect) following an amnesia suggestion. The primary measure of recall order was the rank-order correlation (rho scores) between the presentation order and the recall order of hypnotic experiences computed for each S. Following a suggestion for posthypnotic amnesia, HSs usually obtained lower rho scores than LSs. This research is critically examined, noting methodological shortcomings associated with the susceptibility-scale paradigm, inconsistent findings, and failures to replicate. Two studies are described that found no relationship between susceptibility level and rho scores. These null results held true for Ss who recalled new information after cancellation of the amnesia suggestion (reversers) as well as for those who did not recall new information (nonreversers). Nevertheless, the authors have replicated previous work on differential recall of the 1st item. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subjective and categorical organization of recall during posthypnotic amnesia.

Conducted 2 experiments to determine the fate of organization of recall during posthypnotic amnesia. In both studies, amnesia suggestions were administered to undergraduate Ss of low, medium, and high hypnotic susceptibility who had learned a word list by the method of free recall while they were hypnotized. In Exp I (n?=?44), words were unrelated to each other, and subjective organization was measured by raw and adjusted pair frequency. In Exp II (n?=–&59), words were drawn from various taxonomic categories, and category clustering was measured by repetition ratio, modified repetition ratio, and adjusted ratio of clustering. Results indicate that, compared to baseline levels, subjective organization and category clustering did not decrease reliably during the time the amnesia suggestion was in effect. Moreover, these aspects of strategic organization were not significantly correlated with the number of items recalled during amnesia. Both findings contrast with previous results concerning temporal organization of a word list memorized by the method of serial learning. Findings suggest that the disruption of retrieval processes in posthypnotic amnesia may be limited to certain organizational schemes. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some characteristics of posthypnotic amnesia.

This experiment investigated (a) the differences in post-hypnotic amnesic characteristics of Ss with high and low hypnotic susceptibility and (b) the extent of the amnesia. The experimental Ss were presented 6 words under hypnosis with instructions for amnesia. The simulation Ss pretended they were hypnotized and received the words with instructions for posthypnotic amnesia. The control Ss were given the words with instructions only to remember them. Recognition, recall, and associative tests, administered immediately after, assessed the amnesia. Posthypnotic amnesia impaired recall and recognition among the experimental Ss, but did not reduce the availability of the words as associative responses. The simulating Ss overplayed their amnesic role and also showed impaired performance on the associative tests. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clinical hypnosis: Differential impact on volitional and nonvolitional disorders.

Presents a conceptualization of hypnosis that differentiates the effects of the hypnotic experience from the effects of the hypnotic context. Within this framework, the clinical impact of hypnotic techniques on disorders that are usually not under volitional control (e.g., pain and asthma) as well as on those that are essentially problems of self-control (e.g., smoking and obesity) is examined. Findings generally indicate that whereas the hypnotic experience is responsible for therapeutic gain in the former type of disorder, it is the hypnotic context that affords such gain in the latter type. (French abstract) (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attempting to breach posthypnotic amnesia.

Traditionally, posthypnotic amnesia has been construed as a subjectively compelling deficit in memory retrieval. Alternatively, it may represent a motivated failure to utilize appropriate retrieval cues, lack of effort in recall, active suppression of memory, or unwillingness to verbalize the critical material. In an effort to test the alternative hypothesis of amnesia, 488 college students were presented with 4 kinds of instructions (using 4 modifications of the Harvard Group Scale of Hypnotic Susceptibility, Form A) designed to overcome the effects of suggested posthypnotic amnesia. The instructions particularly affected Ss of low and moderate hypnotizability who failed the criterion for amnesia. For those of moderate and high hypnotizability who met the criterion for amnesia, however, explicit requests for temporal organization, exhortations to maximize recall, and demands for honesty in reporting produced no greater effect on memory than did a simple retest. Results place some boundaries on both the traditional and alternative views of posthypnotic amnesia and invite further exploration of both cognitive and contextual models of the phenomenon. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Restricted use of success cues in retrieval during posthypnotic amnesia.

Evaluated memory for successful and unsuccessful responses to hypnotic suggestions in partially amnesic Ss and in those Ss with normal forgetting. Two analyses (278 undergraduates) demonstrated that highly hypnotizable Ss experiencing partial posthypnotic amnesia tended to show no selective recall for their successes or failures during amnesia, whereas the remainder of the Ss showed definite selective recall of hypnotic success posthypnotically. These findings support F. J. Evans and J. F. Kihlstrom's (see record 1974-06307-001) hypothesis that posthypnotic amnesia involves a disruption of memory organization and suggest that the phenomenon may be mediated by a restriction in the use of normally employed retrieval cues. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Episodic and semantic memory in posthypnotic amnesia: A reevaluation.

J. F. Kihlstrom (see record 1980-11245-001) hypothesized that posthypnotic amnesia involved a dissociation between episodic and semantic components of memory. The present study tested an alternative hypothesis that Kihlstrom's findings resulted from experimental demands conveyed by the wording of the amnesia suggestion he employed. It was hypothesized that hypnotically amnesic Ss would show performance deficits on semantic and episodic memory tasks if expectations for such deficits were subtly conveyed to them. Using 2 treatment conditions, 60 undergraduates were divided into susceptibility groups. Condition 1 replicated Kihlstrom's experiment; in Condition 2, Ss were given an alternative hypnotic suggestion. It was found that Ss 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. 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. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Residual effect of suggestions for posthypnotic amnesia: A reexamination.

Despite the significant recovery of memory observed after suggestions for posthypnotic amnesia are canceled, there still remains an apparent deficit in total recall (after amnesia has been lifted) among Ss who show amnesia on initial testing. This effect, reported originally by E. R. Hilgard and L. S. Hommel (1961), was confirmed in analyses of recall data from groups of 691 and 488 volunteer college students (Exps I and II, respectively) who were administered a standardized, tape-recorded hypnotic procedure. Hypnotizable Ss who initially showed posthypnotic amnesia recalled significantly fewer items after amnesia was removed than did hypnotizable Ss who were initially nonamnesic. Further analysis showed that the residual amnesia effect was not an artifact of the very low level of posthypnotic recall performance shown by pseudoamnesic Ss, failure of memory storage due to such factors as inattention or sleep, or the differential time constraints on the memory reports of previously amnesic and nonamnesic Ss. Residual posthypnotic amnesia may reflect the fact that suggested posthypnotic amnesia, when lifted, takes time to fully dissipate. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Volitional experiences associated with breaching posthypnotic amnesia.

40 highly responsive hypnotic undergraduates were selected on the basis of the Harvard Group Scale of Hypnotic Susceptibility—Form A and were classified as having control over remembering (voluntaries) or not having control over remembering (involuntaries) during posthypnotic amnesia. Ss rerated their voluntariness after the experiment. Two contextual conditions were employed: a lie detector condition meant to create pressure to breach amnesia and a relaxation control condition. In contrast to earlier findings, the recall data show that both voluntary and involuntary Ss breached under the lie detector condition compared with their counterparts in the relaxation condition, although the degree of breaching was not great in any condition. Results are discussed as they relate to studies attempting to breach posthypnotic amnesia and to characteristics of the voluntary–involuntary dimension. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recovery of memory after posthypnotic amnesia

Notes that documentation of the reversibility of posthypnotic amnesia has been hampered by the correlation of hypnotizability with the initial level of response to amnesia suggestions. 691 college students were placed in groups differing in hypnotic susceptibility that could be matched for initial amnesia recall, thereby eliminating the ceiling effect. At virtually every point along the distribution of initial amnesia response, hypnotizable Ss were significantly better able than insusceptible Ss to recapture the previously blocked memories after the amnesia suggestion was lifted. Conversely, those Ss who showed reversibility of amnesia were more responsive overall to hypnosis than those who did not. It is concluded that reversibility is of value in distinguishing between amnesia and pseudoamnesia and between partial amnesia and nonamnesia. Furthermore, reversibility helps define posthypnotic amnesia as a process involving the disruption of retrieval processes in memory. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increasing contextual pressures to breach posthypnotic amnesia.

The study investigated conditions that produce strong social pressures on posthypnotically amnesic Ss to remember more before being given the cue to remove amnesia. Highly susceptible Ss who passed posthypnotic amnesia were classified as voluntary or involuntary (having high or low control over recall). Test Ss were serially subjected to 3 pressure situations before being given the cue to lift amnesia: (a) instructions to be honest, (b) lie detection, and (c) a replay of a video of the session. Control Ss sat for the same amount of time and were only asked if they could remember anything else while the experimental Ss received pressure recalls. All but 1 S breached in the experimental condition. Only the voluntary Ss breached in the control condition. Results are discussed as they relate to breaching amnesia and the voluntary dimension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disrupted retrieval in directed forgetting: A link with posthypnotic amnesia.

Findings from research on directed forgetting seem difficult to accommodate in terms of theoretical processes, such as selective rehearsal or storage differentiation, that have been put forward to account for directed-forgetting phenomena. Some kind of "missing mechanism" appears to be involved. To circumvent the methodological constraints that have limited the conclusions investigators could draw from past experiments, the present author describes a new paradigm that includes a mixture of intentional and incidental learning. Four experiments with 234 undergraduates tested the paradigm. A midlist instruction to forget the 1st half of a list was found to reduce later recall of the items learned incidentally as well as those learned intentionally. This result suggests that a cue to forget can lead to a disruption of retrieval processes as well as to alteration of encoding processes postulated in prior theories. Results also provide a link between intentional forgetting and the literature on posthypnotic amnesia, in which disrupted retrieval has been implicated. With each of these procedures, the information that can be remembered is typically recalled out of order and often with limited recollection for when the information had been presented. It is concluded that retrieval inhibition plays a significant role in nonhypnotic as well as in hypnotic instances of directed forgetting. The usefulness of retrieval inhibition as a mechanism for memory updating is discussed. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnosis as a retrieval cue in posthypnotic amnesia.

Tested the effectiveness of hypnosis as a retrieval cue in a group of 80 highly hypnotizable college students who demonstrated posthypnotic amnesia on an initial recall test. The 40 Ss who received a reinduction of hypnosis showed a significant improvement in memory on a retest; there was a significant loss of memory on a 3rd test following termination of the 2nd hypnosis and a more substantial recovery on a 4th test following administration of a prearranged reversibility cue. Another 40 Ss, who merely relaxed before the 2nd test, showed a similar improvement in memory on the retest but no subsequent memory loss. The amount of trial-to-trial improvement in memory shown by Ss was unaffected by explicit instructions to maintain amnesia until the reversibility cue had been given. It is concluded that posthypnotic amnesia is not a case of state-dependent retention, nor does hypnosis provide retrieval cues that can lead to the emergence of previously unrecalled memories. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed forgetting and posthypnotic amnesia: Information processing and social contexts.

In three experiments we compared posthypnotic amnesia (PHA) with directed forgetting (DF), evaluating subjects' hypnotic susceptibility, hypnotized or not. Experiment 1 suggested that the memory processes in PHA and DF were not the same. Low and high susceptibility subjects responded differently in the two contexts. Experiment 2 demonstrated a context effect for highly susceptible subjects: They showed the usual DF response outside hypnosis but not during hypnosis. Experiment 3 showed that high and low susceptibility subjects responded similarly to DF instructions outside hypnosis, eliminating the susceptibility as an important variable in the DF response. We concluded: (a) The interaction of context and susceptibility was the important determinant of unusual DF responses for high susceptibles, and (b) information processing concepts are too limited to explain PHA and perhaps DF. Theories that include interactions appear necessary for an accurate understanding of hypnotic phenomena and perhaps some phenomena usually focused on by cognitive psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social psychological factors in the genesis of posthypnotic source amnesia.

Three experiments assessed the role of social psychological variables in source amnesia. Experiment 1 found that low-hypnotizable subjects instructed to simulate partial amnesia were more likely to exhibit source amnesia than high-hypnotizable hypnotic or task-motivated subjects. Experiment 2 found equivalent rates of source amnesia in low-hypnotizable simulators and high-hypnotizable hypnotic subjects. In addition, the findings of Experiment 2 failed to support the idea that the instructions for partial amnesia given to simulators cued for the occurrence of source of amnesia as well as for the occurrence of partial amnesia. In Experiment 3, preliminary instructions that legitimated source amnesia as a role-appropriate response produced significantly more posthypnotic source amnesia than did neutral or no instructions. Together, the findings of the 3 experiments support the relation of source amnesia to experimental demands and subjects' expectations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The impact of videotape playback of hypnotic events on posthypnotic amnesia.

Examined the breakdown of amnesia by showing 48 hypnotic and nonhypnotic undergraduates (Harvard Group Scale of Hypnotic Susceptibility) a videotape of the hypnotic events they had experienced. The extent of the amnesia for these events was defined precisely, and simulating procedures were employed to analyze the cues in the overall test situation. Videotape display of the hypnotic events was presented via the Experiential Analysis Technique and served to optimize conditions for breakdown. Some hypnotic Ss' amnesia could not be broken down even though they were exposed via videotape playback to the events to be recalled and when suggestions for the period of amnesia were quite explicit. Simulators showed breaching of amnesia but attributed their recall to the videotape rather than to the hypnotic session. Hypnotic Ss were distinctive in their inability to recall experiential aspects of their performance even though they could recall behavioral aspects. The data are discussed in relation to the hypothesis that dissociative cognitive mechanisms underlie posthypnotic amnesia. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recall and recognition memory during posthypnotic amnesia: A failure to confirm the disrupted-search hypothesis and the memory disorganization hypothesis.

Tested hypotheses that posthypnotic amnesia is characterized by a disruption in the memory search process and, more generally, by disorganization in memory retrieval. 141 undergraduates were administered the Stanford Hypnotic Susceptibility Scales, Forms B and C. Amnesia was assessed by the usual recall criterion and by a batch recognition-testing procedure. The disrupted-search hypothesis, tested by comparing the effects of the amnesia suggestion on recall and recognition, was not supported. The use of recognition items, rank ordered by Ss according to their judgment of order of administration, furnished data to test the memory disorganization hypothesis. In support of this hypothesis, analyses of the temporal rankings of recognized items revealed greater disorganization in the memory of Ss who were initially amnesic by recall criteria than those who were partially amnesic or nonamnesic. Nevertheless, other findings, including the fact that fewer than 50% of the initially amnesic Ss showed disorganized recognition and that the disorganization effect during recall was weak and inconsistent, call into question the explanatory power of this hypothesis. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of expectancy, amnesia, and hypnotic induction in the performance of posthypnotic behavior.

Studied posthypnotic behavior in 54 female undergraduates. Except for controls, Ss were instructed to resist a posthypnotic suggestion along with either a positive or negative expectation that they would be successful. Ss were given the suggestion either immediately before or after a hypnotic induction. Ss' responses to the suggestion were significantly (p