Giuliana Mazzoni

Publications of Giuliana Mazzoni

• Suggested visual hallucination without hypnosis enhances activity in visual areas of the brain.

  Authors: William J McGeown, Annalena Venneri, Irving Kirsch, Luca Nocetti, Kathrine Roberts, Lisa Foan, Giuliana Mazzoni

  Consciousness and cognition. 11/2011; 21(1):100-16.

  This functional Magnetic Resonance Imaging (fMRI) study investigated high and low suggestible people responding to two visual hallucination suggestions with and without a hypnotic induction.This functional Magnetic Resonance Imaging (fMRI) study investigated high and low suggestible people responding to two visual hallucination suggestions with and without a hypnotic induction. Participants in the study were asked to see color while looking at a grey image, and to see shades of grey while looking at a color image. High suggestible participants reported successful alterations in color perception in both tasks, both in and out of hypnosis, and showed a small benefit if hypnosis was induced. Low suggestible people could not perform the tasks successfully with or without the hypnotic induction. The fMRI results supported the self report data, and changes in brain activity were found in a number of visual areas. The results indicate that a hypnotic induction, although having the potential to enhance the ability of high suggestible people, is not necessary for the effective alteration of color perception by suggestion.

• Personalized and not general suggestion produces false autobiographical memories and suggestion-consistent behavior.

  Authors: Alan Scoboria, Giuliana Mazzoni, Josée L Jarry, Daniel M Bernstein

  Acta psychologica. 11/2011; 139(1):225-32.

  Suggesting false childhood events produces false autobiographical beliefs, memories and suggestion-consistent behavior. The mechanisms by which suggestion affects behavior are not understood, andSuggesting false childhood events produces false autobiographical beliefs, memories and suggestion-consistent behavior. The mechanisms by which suggestion affects behavior are not understood, and whether false beliefs and memories are necessary for suggestions to impact behavior remains unexplored. We examined the relative effects of providing a personalized suggestion (suggesting that an event occurred to the person in the past), and/or a general suggestion (suggesting that an event happened to others in the past). Participants (N=122) received a personalized suggestion, a general suggestion, both or neither, about childhood illness due to spoiled peach yogurt. The personalized suggestion resulted in false beliefs, false memories, and suggestion-consistent behavioral intentions immediately after the suggestion. One week or one month later participants completed a taste test that involved eating varieties of crackers and yogurts. The personalized suggestion led to reduced consumption of only peach yogurt, and those who reported a false memory showed the most eating suppression. This effect on behavior was equally strong after one week and one month, showing a long lived influence of the personalized suggestion. The general suggestion showed no effects. Suggestions that convey personal information about a past event produce false autobiographical memories, which in turn impact behavior.

• "It's a hair-dryer…No, it's a drill": Misidentification-related false recognitions in younger and older adults.

  Authors: Manila Vannucci, Giuliana Mazzoni, Igor Marchetti, Francesca Lavezzini

  Archives of gerontology and geriatrics. 08/2011; 54(2):310-6.

  Memory for visual objects, although typically highly accurate, can be distorted, especially in older adults. Here we asked whether also erroneous identifications of visual objects subsequentlyMemory for visual objects, although typically highly accurate, can be distorted, especially in older adults. Here we asked whether also erroneous identifications of visual objects subsequently corrected and replaced by a correct identification might induce false recognitions, and whether this is more likely to occur in older people. For this aim a new paradigm was developed. In the first phase, participants performed a visual object identification task with degraded pictures of objects and produced correct and false but subsequently corrected identifications. In the second phase, participants performed a surprise recognition task in which also false identifications were presented. False identifications elicited false recognitions, with a stronger and more reliable effect in elderly participants, suggesting that correcting the initial visual error is not sufficient to correct the memory for the experience. Moreover, misidentification-related false recognitions coexisted in memory along with correct recognitions of correct identifications. These findings are discussed in relation with age-related deficits in memory updating and strategic retrieval.

• Both differences in encoding processes and monitoring at retrieval reduce false alarms when distinctive information is studied.

  Authors: Maciej Hanczakowski, Giuliana Mazzoni

  Memory (Hove, England). 04/2011; 19(3):280-9.

  A reduction in false alarms to critical lures is observed in the DRM paradigm (Roediger & McDermott, 1995) when distinctive information is presented at encoding. Two mechanisms have been proposed toA reduction in false alarms to critical lures is observed in the DRM paradigm (Roediger & McDermott, 1995) when distinctive information is presented at encoding. Two mechanisms have been proposed to account for this reduction. According to the monitoring theory (e.g., the distinctiveness heuristic), lack of diagnostic recollection serves as a basis for discarding non-presented lures. According to the encoding theory, presenting distinctive information at study leads to impoverished relational processing, which results in a reduction in memorial information elicited by critical lures. In the present study a condition was created in which the use of the distinctiveness heuristic was precluded by associating, within the same study, lures with distinctive information in a context different from the study session. Under that condition reduction in false alarms to distinctive critical lures was still observed. This result supports the predictions of the encoding theory. However, when in the same study the use of the distinctiveness heuristic was not precluded, reductions in false alarms to unrelated lures were also observed when distinctive information was presented at study, indicating that both mechanisms are likely to contribute to the rejection of false memories.

• Lack of control enhances accurate and inaccurate identification responses to degraded visual objects.

  Authors: Manila Vannucci, Giuliana Mazzoni, Giulia Cartocci

  Psychonomic bulletin & review. 03/2011; 18(3):524-30.

  Recent studies have shown that lack of control induces illusory pattern perception. In this study, we demonstrate that lacking control also affected identification responses to degraded pictures ofRecent studies have shown that lack of control induces illusory pattern perception. In this study, we demonstrate that lacking control also affected identification responses to degraded pictures of visual objects. As compared with control participants, participants in whom lack of control was experimentally induced produced identification responses to visual objects at a significantly higher level of degradation of the stimulus. Lacking control did not influence accuracy of identification, since the effect was present for both correct and incorrect identification responses, and did not encourage pure random guessing. Our results indicate that lacking control makes individuals more prone to achieve visual closure by attempting earlier identifications of perceptually degraded visual objects. Possible mechanisms involved in this effect are discussed.

• Preserved monitoring and control processes in temporal lobe epilepsy.

  Authors: Pilar Andrés, Giuliana Mazzoni, Charlotte E Howard

  Neuropsychology. 11/2010; 24(6):775-86.

  The aim of this study was to assess an aspect of metamemory never examined before in patients with temporal lobe epilepsy (TLE): the ability to upgrade the accuracy of one's memory predictions afterThe aim of this study was to assess an aspect of metamemory never examined before in patients with temporal lobe epilepsy (TLE): the ability to upgrade the accuracy of one's memory predictions after study. Four lists of different levels of difficulty and relatedness were presented to 15 TLE patients and 15 control participants, who were asked to predict their subsequent recall both before and after studying each list. The results showed clear impairment in recall in TLE patients. However, both TLE patients and controls showed an improvement in accuracy in their poststudy predictions compared with their prestudy predictions, showing that both groups were able to upgrade their metamemory predictions. Unexpectedly, prediction accuracy was overall higher in TLE patients than in controls. Moreover, study time was allocated in both groups taking into account the characteristics of the list. These results confirm and extend findings of Howard et al. (2010) of intact metamemory in TLE patients, and provide further support to the dissociation between memory and metamemory in this clinical population.

• Nonbelieved memories.

  Authors: Giuliana Mazzoni, Alan Scoboria, Lucy Harvey

  Psychological science. 09/2010; 21(9):1334-40.

  This is the first empirical study of vivid autobiographical memories for events that people no longer believe happened to them. Until now, this phenomenon has been the object of relatively rare,This is the first empirical study of vivid autobiographical memories for events that people no longer believe happened to them. Until now, this phenomenon has been the object of relatively rare, albeit intriguing, anecdotes, such as Jean Piaget's description of his vivid memory of an attempted abduction that never happened. The results of our study show that nonbelieved memories are much more common than is expected. Approximately 20% of our initial sample reported having at least one nonbelieved autobiographical memory. Participants' ratings indicate that nonbelieved memories share most recollective qualities of believed memories, but are characterized by more negative emotions. The results have important implications for the way autobiographical memory is conceptualized and for the false-memory debate.

• The effects of observation and gender on psychogenic symptoms.

  Authors: Giuliana Mazzoni, Lisa Foan, Michael E Hyland, Irving Kirsch

  Health psychology : official journal of the Division of Health Psychology, American Psychological Association. 03/2010; 29(2):181-5.

  To assess the effects of modeling and its interaction with gender in the production of psychogenic symptoms. Healthy volunteers were asked to inhale an inert substance described as a suspectedTo assess the effects of modeling and its interaction with gender in the production of psychogenic symptoms. Healthy volunteers were asked to inhale an inert substance described as a suspected environmental toxin that had been reported to provoke 4 physical symptoms. Subsequently, half of the participants observed a confederate inhale and display the 4 expected symptoms. To control for the general tendency of women to report more physical symptoms than men, participants were also asked to rate the presence of 4 unexpected symptoms. Symptom ratings at 10-min intervals over a 1-hr period. With unexpected symptoms controlled, observation of symptom displays increased reports of expected symptoms significantly. In addition, the presence of another person of the same gender as the participant increased the production of expected symptoms, even when symptoms were not modeled by the confederate. There was also a trend for women to show more expected symptoms than men. Although the effect of modeling was independent of gender, the mere presence of a same-gender individual, as opposed to a person of the opposite gender, increased reports of expected symptoms, regardless of whether the second person (i.e., the confederate) displayed symptoms.

• Memory, metamemory and their dissociation in temporal lobe epilepsy.

  Authors: Charlotte E Howard, Pilar Andrés, Paul Broks, Rupert Noad, Martin Sadler, Debbie Coker, Giuliana Mazzoni

  Neuropsychologia. 11/2009;

  Patients with temporal-lobe epilepsy (TLE) present with memory difficulties. The aim of the current study was to determine to what extent these difficulties could be related to a metamemoryPatients with temporal-lobe epilepsy (TLE) present with memory difficulties. The aim of the current study was to determine to what extent these difficulties could be related to a metamemory impairment. Fifteen patients with TLE and 15 matched healthy controls carried out a paired-associates learning task. Memory recall was measured at intervals of 30minutes and four weeks. We employed a combined Judgement-of-Learning (JOL) and Feeling-of-Knowing (FOK) task to investigate whether participants could monitor their memory successfully at both the item-by-item level and the global level. The results revealed a clear deficit of episodic memory in patients with epilepsy compared with controls, but, metamemory in TLE patients was intact. Patients were able to monitor their memory successfully at the item-by-item level, and tended to be even more accurate than controls when making global judgements.

• Hypnotic induction decreases anterior default mode activity.

  Authors: William J McGeown, Giuliana Mazzoni, Annalena Venneri, Irving Kirsch

  Consciousness and cognition. 09/2009;

  The 'default mode' network refers to cortical areas that are active in the absence of goal-directed activity. In previous studies, decreased activity in the 'default mode' has always been associatedThe 'default mode' network refers to cortical areas that are active in the absence of goal-directed activity. In previous studies, decreased activity in the 'default mode' has always been associated with increased activation in task-relevant areas. We show that the induction of hypnosis can reduce anterior default mode activity during rest without increasing activity in other cortical regions. We assessed brain activation patterns of high and low suggestible people while resting in the fMRI scanner and while engaged in visual tasks, in and out of hypnosis. High suggestible participants in hypnosis showed decreased brain activity in the anterior parts of the default mode circuit. In low suggestible people, hypnotic induction produced no detectable changes in these regions, but instead deactivated areas involved in alertness. The findings indicate that hypnotic induction creates a distinctive and unique pattern of brain activation in highly suggestible subjects.

• Suggested visual hallucinations in and out of hypnosis.

  Authors: Giuliana Mazzoni, Elisabetta Rotriquenz, Claudia Carvalho, Manila Vannucci, Kathrine Roberts, Irving Kirsch

  Consciousness and cognition. 04/2009;

  We administered suggestions to see a gray-scale pattern as colored and a colored pattern in shades of gray to 30 high suggestible and eight low suggestible students. The suggestions were administeredWe administered suggestions to see a gray-scale pattern as colored and a colored pattern in shades of gray to 30 high suggestible and eight low suggestible students. The suggestions were administered twice, once following the induction of hypnosis and once without an induction. Besides rating the degree of color they saw in the stimuli differently, participants also rated their states of consciousness as normal, relaxed, hypnotized, or deeply hypnotized. Reports of being hypnotized were limited to highly suggestible participants and only after the hypnotic induction had been administered. Reports of altered color perception were also limited to high suggestibles, but were roughly comparable regardless of whether hypnosis had been induced. These data indicate that suggestible individuals do not slip into a hypnotic state when given imaginative suggestions without the induction of hypnosis, but nevertheless report experiencing difficult suggestions for profound perceptual alterations that are pheonomenologically similar to what they report in hypnosis.

• "Don't know" responding to answerable and unanswerable questions during misleading and hypnotic interviews.

  Authors: Alan Scoboria, Giuliana Mazzoni, Irving Kirsch

  Journal of experimental psychology. Applied. 10/2008; 14(3):255-65.

  "Don't know" (DK) responses to interview questions are conceptually heterogeneous, and may represent uncertainty or clear statements about the contents of memory. A study examined the subjective"Don't know" (DK) responses to interview questions are conceptually heterogeneous, and may represent uncertainty or clear statements about the contents of memory. A study examined the subjective intent of DK responses in relation to the objective status of information queried, in the context of memory distorting procedures. Participants viewed a video and responded to answerable and unanswerable questions phrased in misleading or nonmisleading formats, while hypnotized or not hypnotized. Subjective meanings of DK responses were queried, and a recognition measure assessed the contents of memory. Lower DK and accuracy rates were consistently associated with unanswerable and misleading questions. One-third of DK responses were statements that the information had no not presented. When these were recoded, accuracy estimates for answerable questions decreased and more so for hypnotized participants. These results demonstrate that DK responses convey different types of information, thus accuracy estimates in studies that permit DK responses may be misestimated. Robust risks associated with asking unanswerable questions and asking questions at all were observed. Implications for working with DK responses during interviews are discussed. (PsycINFO Database Record (c) 2008 APA, all rights reserved).

• Portuguese norms for the Waterloo-Stanford Group C (WSGC) scale of hypnotic susceptibility.

  Authors: Claudia Carvalho, Irving Kirsch, Giuliana Mazzoni, Isabel Leal

  The International journal of clinical and experimental hypnosis. 08/2008; 56(3):295-305.

  Portuguese norms for the Waterloo-Stanford Group C (WSGC) scale of hypnotic susceptibility are presented. A Portuguese translation of this scale was given to 625 Portuguese college students. ScorePortuguese norms for the Waterloo-Stanford Group C (WSGC) scale of hypnotic susceptibility are presented. A Portuguese translation of this scale was given to 625 Portuguese college students. Score distribution, item analysis, and reliability of the WSGC are presented and compared to three North American samples. The findings show that normative data from the Portuguese sample are congruent with the reference samples. The only significant difference obtained was a lower proportion of participants scoring within the high range of hypnotic suggestibility on the WSGC.

• Suggesting childhood food illness results in reduced eating behavior.

  Authors: Alan Scoboria, Giuliana Mazzoni, Josée L Jarry

  Acta psychologica. 07/2008; 128(2):304-9.

  Previous studies have shown that suggesting childhood events can influence current self-reported attitudes towards future behavior. This study shows that suggesting a false past event (i.e. becomingPrevious studies have shown that suggesting childhood events can influence current self-reported attitudes towards future behavior. This study shows that suggesting a false past event (i.e. becoming sick on a specific food during childhood) can modify present behavior (i.e. reduce eating of the food). Participants screened to be normal eaters received or did not receive a suggestion that they likely became sick on spoiled peach yogurt as a child. One week later they took part in an allegedly separate marketing taste-test study, during which they rated preferences for a variety of crackers and yogurts. After completing ratings, participants were invited to freely eat the remaining food while completing questionnaires. Results revealed that the participants receiving the suggestion expressed lower preference specifically for peach yogurt, and ate less yogurt of all the types, while not differing in eating of crackers. These results demonstrate that suggesting false past events influences subsequent behavior.

• Object imagery and object identification: object imagers are better at identifying spatially-filtered visual objects.

  Authors: Manila Vannucci, Giuliana Mazzoni, Carlo Chiorri, Lavinia Cioli

  Cognitive processing. 06/2008; 9(2):137-43.

  Object imagery refers to the ability to construct pictorial images of objects. Individuals with high object imagery (high-OI) produce more vivid mental images than individuals with low object imageryObject imagery refers to the ability to construct pictorial images of objects. Individuals with high object imagery (high-OI) produce more vivid mental images than individuals with low object imagery (low-OI), and they encode and process both mental images and visual stimuli in a more global and holistic way. In the present study, we investigated whether and how level of object imagery may affect the way in which individuals identify visual objects. High-OI and low-OI participants were asked to perform a visual identification task with spatially-filtered pictures of real objects. Each picture was presented at nine levels of filtering, starting from the most blurred (level 1: only low spatial frequencies--global configuration) and gradually adding high spatial frequencies up to the complete version (level 9: global configuration plus local and internal details). Our data showed that high-OI participants identified stimuli at a lower level of filtering than participants with low-OI, indicating that they were better able than low-OI participants to identify visual objects at lower spatial frequencies. Implications of the results and future developments are discussed.

• The effect of posthypnotic suggestion, hypnotic suggestibility, and goal intentions on adherence to medical instructions.

  Authors: Claudia Carvalho, Giuliana Mazzoni, Irving Kirsch, Maria Meo, Maura Santandrea

  The International journal of clinical and experimental hypnosis. 05/2008; 56(2):143-55.

  The effects of implementation intentions and posthypnotic suggestion were investigated in 2 studies. In Experiment 1, participants with high levels of hypnotic suggestibility were instructed to takeThe effects of implementation intentions and posthypnotic suggestion were investigated in 2 studies. In Experiment 1, participants with high levels of hypnotic suggestibility were instructed to take placebo pills as part of an investigation of how to best enhance compliance with medical instruction. In Experiment 2, participants with high, medium, and low levels of hypnotic suggestibility were asked to run in place, take their pulse rate before, and send an e-mail report to the experimenter each day. Experiment 1 revealed enhanced adherence as a function of both implementation intentions and posthypnotic suggestion. Experiment 2 failed to find any significant main effects but found a significant interaction between suggestibility and the effects of posthypnotic suggestion. Posthypnotic suggestion enhanced adherence among high suggestible participants but lowered it among low suggestibles.

• Hypnotic history: a reply to critics.

  Authors: Irving Kirsch, Giuliana Mazzoni, Guy H Montgomery

  The American journal of clinical hypnosis. 05/2007; 49(4):249-54.

  This article responds to comments on Kirsch, Mazzoni, & Montgomery (2007). Contrary to the perceptions of some commentators, the target article was not aimed at supporting a particular view ofThis article responds to comments on Kirsch, Mazzoni, & Montgomery (2007). Contrary to the perceptions of some commentators, the target article was not aimed at supporting a particular view of hypnosis. Instead, it was a reminder of a long accepted axiom in hypnosis research: the effects of hypnotic suggestions cannot be attributed to hypnosis unless it is demonstrated that the same suggestion does not produce the effect outside of hypnosis.

• False claims about false memory research.

  Authors: Kimberley A Wade, Stefanie J Sharman, Maryanne Garry, Amina Memon, Giuliana Mazzoni, Harald Merckelbach, Elizabeth F Loftus

  Consciousness and cognition. 04/2007; 16(1):18-28; discussion 29-30.

  Pezdek and Lam [Pezdek, K. & Lam, S. (2007). What research paradigms have cognitive psychologists used to study "False memory," and what are the implications of these choices? Consciousness andPezdek and Lam [Pezdek, K. & Lam, S. (2007). What research paradigms have cognitive psychologists used to study "False memory," and what are the implications of these choices? Consciousness and Cognition] claim that the majority of research into false memories has been misguided. Specifically, they charge that false memory scientists have been (1) misusing the term "false memory," (2) relying on the wrong methodologies to study false memories, and (3) misapplying false memory research to real world situations. We review each of these claims and highlight the problems with them. We conclude that several types of false memory research have advanced our knowledge of autobiographical and recovered memories, and that future research will continue to make significant contributions to how we understand memory and memory errors.

• Illness by suggestion: expectancy, modeling, and gender in the production of psychosomatic symptoms.

  Authors: William Lorber, Giuliana Mazzoni, Irving Kirsch

  Annals of behavioral medicine : a publication of the Society of Behavioral Medicine. 03/2007; 33(1):112-6.

  BACKGROUND: Expectancy and modeling have been cited as factors in mass psychogenic illness (MPI), which reportedly affects more women than men. PURPOSE: The purpose of the study is to assess theBACKGROUND: Expectancy and modeling have been cited as factors in mass psychogenic illness (MPI), which reportedly affects more women than men. PURPOSE: The purpose of the study is to assess the effects of expectancy and modeling in a controlled laboratory analogue of MPI. METHODS: Students were randomly assigned to inhale or not inhale an inert placebo described as a suspected environmental toxin that had been linked to four symptoms typical of reported instances of MPI. Half of the students observed a female confederate inhale the substance and subsequently display the specified symptoms. RESULTS: Students who inhaled the placebo reported greater increases in symptoms, and the increase was significantly greater for the specified symptoms than for other symptoms. Observation of the confederate displaying symptoms increased specified symptoms significantly among women but not among men. Changes in reported symptoms were significantly associated with changes in unobtrusively observed behavior. CONCLUSIONS: Symptoms typical of clinical reports of MPI can be induced by manipulating response expectancies, and the effects are specific rather than generalized. Among women, this effect is enhanced by observing another participant (who in this study is also female) display symptoms. This suggests that the preponderance of women showing symptoms in outbreaks of MPI may be due to gender-linked differences in the effects of modeling on psychogenic symptoms.

• Remembrance of hypnosis past.

  Authors: Irving Kirsch, Giuliana Mazzoni, Guy H Montgomery

  The American journal of clinical hypnosis. 02/2007; 49(3):171-8; discussion 179-80, 183-4.

  The history of the most enduring experimental design in hypnosis research is reviewed. More than 75 years of research converge to indicate that: (1) all of the phenomena produced in hypnosis byThe history of the most enduring experimental design in hypnosis research is reviewed. More than 75 years of research converge to indicate that: (1) all of the phenomena produced in hypnosis by suggestion also can be produced by suggestion without the induction of hypnosis, (2) the induction of hypnosis produces a relatively small increase in responsiveness to suggestion, and (3) hypnotic and waking suggestion are highly correlated, in many cases rivalling the reliability of the suggestibility measure. The importance of these data to both clinical and experimental hypnosis is emphasized.