Using hypnosis to model Fregoli delusion and the impact of challenges on belief revision.

Fregoli delusion involves the belief that strangers are known people in disguise. We aimed to model aspects of this delusion for the first time using hypnosis. We informed hypnotised subjects that someone would enter the room (a confederate) and they would believe this person was someone they knew in disguise. After testing their reaction to the confederate, we challenged their delusion by directly contradicting their belief and then asking them to focus on the confederate's voice and gait. Finally, we indexed whether they could identify photographs of the confederate. We found that just over half of our high hypnotisable subjects identified the confederate as someone they knew in disguise. Although many highs abandoned their belief in response to challenges, some maintained strong, unwavering conviction that the confederate was a known person. We discuss these findings in terms of how evidence might be evaluated during both hypnotic and clinical delusions.

Hypnotic Olfactory Hallucinations.

Olfactory hallucinations (smelling odors that are not present) are intrusive and disruptive yet challenging to investigate because they cannot be produced on demand. In this study, the authors attempted to model olfactory hallucinations using hypnotic suggestions. We gave some subjects a suggestion to smell an odor in the absence of a real odor (positive hallucination) and gave others a suggestion to smell nothing in the presence of a real odor (negative hallucination). High hypnotizable individuals who received the positive hallucination reported intense smells whereas those who received the negative hallucination reported a reduction in intensity. These suggestions also influenced later recall about frequency of odor presentation. Findings are discussed in terms of reality monitoring and differences between positive and negative hallucinations.

A hypnotic analogue of clinical confabulation.

Confabulation-fabricated or distorted memories about oneself-occurs in many disorders, but there is no reliable technique for investigating it in the laboratory. The authors used hypnosis to model clinical confabulation by giving subjects a suggestion for either (a) amnesia for everything that had happened since they started university, (b) amnesia for university plus an instruction to fill in memory gaps, or (c) confusion about the temporal order of university events. They then indexed different types of memory on a confabulation battery. The amnesia suggestion produced the most confabulation, especially for personal semantic information. Notably, subjects confabulated by making temporal confusions. The authors discuss the theoretical implications of this first attempt to model clinical confabulation and the potential utility of such analogues.

Using hypnosis to disrupt face processing: mirrored-self misidentification delusion and different visual media.

Mirrored-self misidentification delusion is the belief that one's reflection in the mirror is not oneself. This experiment used hypnotic suggestion to impair normal face processing in healthy participants and recreate key aspects of the delusion in the laboratory. From a pool of 439 participants, 22 high hypnotisable participants ("highs") and 20 low hypnotisable participants were selected on the basis of their extreme scores on two separately administered measures of hypnotisability. These participants received a hypnotic induction and a suggestion for either impaired (i) self-face recognition or (ii) impaired recognition of all faces. Participants were tested on their ability to recognize themselves in a mirror and other visual media - including a photograph, live video, and handheld mirror - and their ability to recognize other people, including the experimenter and famous faces. Both suggestions produced impaired self-face recognition and recreated key aspects of the delusion in highs. However, only the suggestion for impaired other-face recognition disrupted recognition of other faces, albeit in a minority of highs. The findings confirm that hypnotic suggestion can disrupt face processing and recreate features of mirrored-self misidentification. The variability seen in participants' responses also corresponds to the heterogeneity seen in clinical patients. An important direction for future research will be to examine sources of this variability within both clinical patients and the hypnotic model.

A laboratory analogue of mirrored-self misidentification delusion: the role of hypnosis, suggestion, and demand characteristics.

Mirrored-self misidentification is the delusional belief that one's own reflection in the mirror is a stranger. In two experiments, we tested the ability of hypnotic suggestion to model this condition. In Experiment 1, we compared two suggestions based on either the delusion's surface features (seeing a stranger in the mirror) or underlying processes (impaired face processing). Fifty-two high hypnotisable participants received one of these suggestions either with hypnosis or without in a wake control. In Experiment 2, we examined the extent to which social cues and role-playing could account for participants' behaviour by comparing the responses of 14 hypnotised participants to the suggestion for impaired face processing (reals) with those of 14 nonhypnotised participants instructed to fake their responses (simulators). Overall, results from both experiments confirm that we can use hypnotic suggestion to produce a compelling analogue of mirrored-self misidentification that cannot simply be attributed to social cues or role-playing.

Transmitting delusional beliefs in a hypnotic model of folie à deux.

Folie à deux is the transference of delusional ideas from one 'primary' individual to one or more 'secondary' individuals (Lasègue & Falret, 1877). However, it is difficult to investigate experimentally because often only one patient is identified as delusional. We investigated whether hypnosis could model the experiences of the secondary in this delusion. Our primary was a confederate, who displayed two delusional beliefs and attempted to transmit them to hypnotised subjects. We manipulated the status of the confederate so that they were portrayed as either "credible" or merely "interesting".Many high hypnotisable individuals adopted the confederate's beliefs and confabulated evidence in support of them.Also, subjects who interacted with a credible confederate extended their delusions beyond those displayed by the confederate. We discuss the strengths and limitations of this approach and suggest ways to improve the validity of this model.

Shifting self, shifting memory: testing the self-memory system model with hypnotic identity delusions.

According to Conway's self-memory system (SMS) model, autobiographical memories may be facilitated, inhibited, or misremembered to be consistent with current self. In 3 experiments, the authors tested this by hypnotically suggesting an identity delusion and indexing whether this shift in self produced a corresponding shift in autobiographical memory. High hypnotizable participants displayed a compelling identity delusion and elicited specific autobiographical events that they could justify when challenged. These memories were reinterpretations of previous experiences that supported the suggested identity. Importantly, autobiographical memories that were no longer consistent with the hypnotically deluded self were less accessible than other memories. The authors discuss these findings in the context of Conway's SMS model and propose 2 accounts of autobiographical remembering during hypnotic and clinical delusions.

Mirror agnosia and the mirrored-self misidentification delusion: a hypnotic analogue.

INTRODUCTION: Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. Current theories suggest that one pathway to the delusion is mirror agnosia (a deficit in which patients are unable to use mirror knowledge when interacting with mirrors). This study examined whether a hypnotic suggestion for mirror agnosia can recreate features of the delusion. METHOD: Ten high hypnotisable participants were given either a suggestion to not understand mirrors or to see the mirror as a window. Participants were asked to look into a mirror and describe what they saw. Participants were tested on their understanding of mirrors and received a series of challenges. Participants then received a detailed postexperimental inquiry. RESULTS: Three of five participants given the suggestion to not understand mirrors reported seeing a stranger and maintained this belief when challenged. These participants also showed signs of mirror agnosia. No participants given the suggestion to see a window reported seeing a stranger. CONCLUSION: Results indicate that a hypnotic suggestion for mirror agnosia can be used to recreate the mirrored-self misidentification delusion. Factors influencing the effectiveness of hypnotic analogues of psychopathology, such as participants' expectations and interpretations, are discussed.

Modeling erotomania delusion in the laboratory with hypnosis.

Erotomania is the delusional belief that one is loved from afar by another person (the target). This study used hypnosis as a novel cognitive neuropsychological research tool to model erotomania. The authors developed 2 versions of a hypnotic erotomania suggestion and tested their impact by asking subjects to recall and interpret a story featuring ambiguous scenarios. They also challenged the delusion by asking subjects to justify their beliefs. The hypnotic erotomania suggestions successfully recreated the features of the clinical delusion for many high hypnotizable subjects. They believed that the target loved them, interpreted ambiguous information consistent with this belief and confabulated evidence in service of their delusion. Some also resisted all challenges to their delusion. These features are strikingly similar to clinical cases and highlight the value of using hypnosis to model clinical delusions. The authors also discuss some limitations of this approach.

Mirrored-self misidentification in the hypnosis laboratory: recreating the delusion from its component factors.

INTRODUCTION: Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. According to Langdon and Coltheart's (2000) "two-factor" theory of monothematic delusions, the delusion can arise from deficits in face processing (Factor 1) and belief evaluation (Factor 2). This study gave participants separate hypnotic suggestions for these two factors to create a hypnotic analogue of the delusion. METHOD: Forty-six high hypnotisable participants received a hypnotic suggestion for either Factor 1 alone or for Factors 1 and 2, either with hypnosis (hypnosis condition) or without (wake condition). Participants were asked to look into a mirror and to describe what they saw. Participants who reported seeing a stranger in the mirror also received a series of challenges. RESULTS: Overall, 70% of participants in the hypnosis condition passed the delusion; only 22% of participants in the wake condition passed. Importantly, in hypnosis, the Factor 1 alone suggestion was just as effective in creating the delusion as the combined Factor 1 and Factor 2 suggestion. CONCLUSION: These results suggest that hypnotic suggestion can recreate the mirrored-self misidentification delusion from its component factors. Notably, the hypnotic context, itself known to disrupt belief evaluation, can act as Factor 2.

"That's not my arm": a hypnotic analogue of somatoparaphrenia.

INTRODUCTION: "Instrumental hypnosis" allows researchers to model clinical symptoms in the laboratory, creating "virtual patients" with reversible disturbances in, for example, perception, action, memory, or belief. We used hypnosis to temporarily recreate somatoparaphrenia, a delusional belief that one's own limb belongs to someone else. METHODS: We compared a "Fully Formed" somatoparaphrenia suggestion with a "Factor 1 + Factor 2" suggestion that attempted to generate the delusional belief from analogues of its hypothesised underlying factors (i.e., paralysis plus disrupted critical belief evaluation). We tested and then challenged subjects' responses to these suggestions. RESULTS: Although many hypnotic subjects experienced temporary paralysis, only a minority claimed their arm did not belong to them. Notably, the Fully Formed suggestion was more successful in recreating features of somatoparaphrenia than the Factor 1 + Factor 2 suggestion. In response to the challenges, some of those who developed temporary somatoparaphrenia maintained their belief throughout the hypnosis session. CONCLUSIONS. We discuss these findings in terms of the "two-factor" theory of delusions and we highlight the advantages versus disadvantages of using hypnosis to explore such delusional beliefs in the laboratory.

A stranger in the looking glass: developing and challenging a hypnotic mirrored-self misidentification delusion.

This article describes a study that used hypnosis to temporarily re-create mirrored-self misidentification, which is the delusional belief that the person one sees in the mirror is a stranger. Following a hypnotic suggestion to see a stranger in the mirror, high hypnotizable subjects described seeing a stranger with physical characteristics different to their own. Whereas subjects' beliefs about seeing a stranger were clearly false, they had no difficulty generating sensible reasons to explain the stranger's presence. The authors tested the resilience of this belief with clinically inspired challenges. Although visual challenges (e.g., the hypnotist appearing in the mirror alongside the subject) were most likely to breach the delusion, some subjects maintained the delusion across all challenges. Findings are discussed in light of the dominant theory of delusions and highlight the advantages of using hypnosis to explore delusional beliefs.

Hypnotic illusions and clinical delusions: hypnosis as a research method.

INTRODUCTION: Hypnosis is not only intrinsically interesting, but it can be used instrumentally as a powerful tool to investigate phenomena outside its immediate domain. In focusing on instrumental hypnosis research, we first sketch the many contributions of hypnosis across a range of areas in experimental psychopathology. In particular, we summarise the historical and more recent uses of hypnosis to create and explore clinically relevant, temporary delusions. METHODS: We then describe in detail the steps that hypnosis researchers take in constructing a hypnotic paradigm to map the features and processes shared by clinical and hypnotic delusions, as well as their impact on information processing (including autobiographical memory). We illustrate with hypnotic versions of mirrored-self misidentification, somatoparaphrenia, alien control, and identity delusions. RESULTS: Finding indicate that hypnotic analogues can produce compelling delusions with features that are strikingly similar to their clinical counterparts. These similarities encompass phenomenological features of delusions, delusional resistance to challenge, and autobiographical memory during delusions. CONCLUSIONS: We recognise important methodological issues and limitations of such hypnotic analogues, including: indexing response (behaviour vs. experience), alternative explanations (e.g., social compliance), the need for converging data, the need for close and continuing dialogue between the clinic and the laboratory, and generalisability of the findings.

Hypnotic illusions and clinical delusions: a hypnotic paradigm for investigating delusions of misidentification.

In 2 experiments, the authors created a hypnotic analogue of delusions of misidentification and explored their impact on autobiographical memory. In Experiment 1, to establish the paradigm, high and low hypnotizable participants were given a suggestion to become someone similar or dissimilar to themselves. In Experiment 2, to further test the paradigm and to examine autobiographical remembering, highs were given a suggestion to become a same-sex sibling, administered 2 challenges to the temporary delusion, and asked to generate autobiographical memories. For high hypnotizable participants, the suggested delusions of misidentification were compelling and resistant to challenge. During these temporary delusions, participants generated specific autobiographical memories that reflected previously experienced events viewed from the perspective of the suggested identity. These findings highlight the instrumental value of hypnosis to the investigation and understanding of delusions and autobiographical memory.

Developing hypnotic analogues of clinical delusions: mirrored-self misidentification.

INTRODUCTION: Despite current research interest in delusional beliefs, there are no viable models for studying delusions in the laboratory. However, hypnosis offers a technique for creating transient delusions that are resistant to challenge. The aim of this study was to develop an hypnotic analogue of one important delusion, mirrored-self misidentification. METHODS: Twelve high hypnotisable participants received an hypnotic suggestion to see either a stranger in the mirror, a mirror as a window, or a mirror as a window with a view to a stranger. Participants' deluded beliefs were challenged, and following hypnosis, Sheehan and McConkey's (1982) Experiential Analysis Technique was used to explore participants' phenomenological experience of the delusion. RESULTS: The majority of participants did not recognise their reflection in the mirror, described the person in the mirror as having different physical characteristics to themselves, and maintained their delusion when challenged. CONCLUSIONS: The hypnotic suggestion created a credible, compelling delusion with features strikingly similar to clinical cases of mirrored-self misidentification. Our findings suggest that Factor 2 within Langdon and Coltheart's (2000) two-factor framework may involve a lowering of the criteria used to accept or reject delusional hypotheses.

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 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.