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Harald Merckelbach

Publications and source records attributed to Harald Merckelbach.

At least 19 recordsLinked to original sources
PubMed2006

False claims about false memory research.

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 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.

Child↗
PubMed2006

Traumatic memories of war veterans: not so special after all.

Several authors have argued that traumatic experiences are processed and remembered in a qualitatively different way from neutral events. To investigate this issue, we interviewed 121 Croatian war veterans diagnosed with posttraumatic stress disorder (PTSD) about amnesia, intrusions (i.e., flashbacks and nightmares), and the sensory qualities of their most horrific war memories. Additionally, they completed a self-report scale measuring dissociative experiences. In contrast to what one would expect on the basis of theories emphasizing the special status of traumatic memories, amnesia, and high frequency intrusions were not particularly typical for our sample of traumatized individuals. Moreover, traumatic memories were not qualitatively different from neutral memories with respect to their stability and sensory qualities. The severity of PTSD symptoms was not significantly correlated with dissociative experiences. Our findings do not support the existence of special memory mechanisms that are unique to experiencing traumatic events.

Adult↗
PubMed2006

The false fame illusion in people with memories about a previous life.

The present study examined whether individuals with full-blown memories of highly implausible events are prone to commit source monitoring errors. Participants reporting previous-life memories and those without such memories completed a false fame task. This task provides an index of source monitoring errors (i.e., misclassifying familiar non-famous names as famous names). Participants with previous-life memories had a greater tendency to judge the names of previously presented non-famous people as famous than control participants. The two groups did not differ in terms of correct recognition of new non-famous names and famous names. Although dissociation, cognitive failures, sleep-related experiences, depressive symptoms, and signs of psychological distress were all significantly higher in participants with previous-life memories than in controls, these variables did not predict the false fame illusion.

Adult↗
PubMed2006

The effect of acute stress on memory depends on word valence.

The present study investigated the effect of acute stress on working memory and memory for neutral, emotionally negative, and emotionally positive words in healthy undergraduates. Participants (N=60) were exposed to either the Trier Social Stress Test (stress group) or a non-stressful task (control group). Analyses of salivary cortisol samples taken throughout the study showed elevated glucocorticoid levels after the experimental manipulation in the stress group, but not in the control group. Recall performance was impaired in the stress group, but only so for neutral words. No differences between the stress and control group were found on working memory measures. For the stress group, digit span forward and digit span total scores were associated with correct recall of neutral words. All in all, this study lends further support to the notion that the memory effects of exposure to acute stress depend on the valence of the memory material.

Adolescent↗
PubMed2006

Symptom overreporting and recovered memories of childhood sexual abuse.

The authenticity of recovered memories is a much debated issue. Surprisingly, no study has systematically looked at symptom overreporting in people claiming recovered memories of childhood sexual abuse (CSA). In a first sample we administered the Structured Inventory of Malingered Symptomatology (SIMS) to individuals who said they had recovered CSA memories (n=66), individuals who said their CSA had always been accessible (continuous CSA memory group; n=119), and controls who said they had no CSA experiences (n=83). In a second sample individuals reporting recovered (n=45) or continuous (n=45) CSA memories completed the Morel Emotional Numbing Test (MENT). Our aim was to compare these groups with regard to their tendency to overreport symptoms. The results indicate that people with recovered memories do not score higher on the SIMS and the MENT than other CSA survivors suggesting that symptom overreporting is not typical for people reporting recovered memories.

Adult↗
PubMed2006

Mild executive dysfunctions in undergraduates are related to recollecting words never presented.

The aim of this study was to explore whether individual differences in executive function in undergraduate students (n = 72) contribute to false recall and recognition as obtained with the Deese/Roediger-McDermott (DRM) paradigm. Participants were subjected to the DRM paradigm and also were given a test designed to assess executive function--the Random Number Generation task (RNG). A relationship was found between heightened seriation on the RNG (indicating a deficiency in the ability to inhibit cognitive schemes) and false recognition of non-presented, critical lure words in the DRM paradigm. This suggests that individual differences in executive function do occur in a healthy population and that the reconstructive activity inherent in memory depends in part on executive functioning.

Adolescent↗
PubMed2006

Dissociation, resting EEG, and subjective sleep experiences in undergraduates.

In this study, we explored whether individual differences in dissociation are related to certain resting electroencephalographic (EEG) parameters. Baseline EEG with eyes open and closed was recorded in an undergraduate sample (N = 67). Cortical power in the alpha range was inversely related to dissociative symptoms as measured by the Dissociative Experiences Scale, while both delta and theta power where positively related to dissociation. However, sleep experiences, as indexed with the Iowa Sleep Experiences Survey, were unrelated to resting EEG characteristics. We propose that suppression in the alpha band and raised levels of theta activity, which are typical for high dissociators, might help to explain why dissociative symptoms are accompanied by attentional and memory deficits.

Adolescent↗
PubMed2006

Detecting malingering of Ganser-like symptoms with tests: a case study.

A middle-aged man presented with Ganser symptoms. He had been involved in a car crash and was seeking disability insurance benefits. Extensive testing with malinger instruments revealed that he performed below chance on simple memory tests and endorsed a variety of nonexistent symptoms. With this in mind, the authors collected collateral information which showed that the patient was involved in high level sports activities that were difficult to reconcile with the severe cognitive dysfunctions that he claimed to suffer from. The case demonstrates that Ganser-like symptoms deserve close scrutiny, preferably with malinger tests.

Accidents, Traffic↗
PubMed2006

Forgetting of prior remembering in persons reporting recovered memories of childhood sexual abuse.

Case studies of individuals reporting recovered memories of childhood sexual abuse suggest that some overestimate their prior forgetting of the abuse. People reporting recovered or continuous memories of childhood sexual abuse and control subjects reporting no history of abuse participated in two experiments examining this "forgot it all along" phenomenon. Participants in Experiment 1 were more likely to forget that they had previously recalled a studied item if they were cued to think of it differently on two recall tests than if they were cued to think of it in the same way on the two tests. This effect was stronger for recovered-memory participants than for continuous-memory and control participants. In Experiment 2, participants recalled autobiographical events three times over a period of 4 months. Much as in Experiment 1, they underestimated prior remembering when the events had been recalled in a different emotional frame (positive vs. negative) on the previous occasion. This underestimation was more pronounced for recovered-memory participants than for continuous-memory and control participants.

Adult↗
PubMed2005

Long term consequences of suppression of intrusive anxious thoughts and repressive coping.

The current experiment employed a thought suppression paradigm to investigate whether repressors (N=40) are more skilled in suppressing positive and anxious autobiographical thoughts than low anxious (N=40), high anxious (N=40), and defensive high anxious (N=40) individuals, both immediately and over a longer time period (i.e., 7 days). Regardless of suppression instructions, repressors reported during their lab visit fewer target thoughts for their most anxious events than participants in the other three groups. However, over a 7 days period, repressors showed the highest number of intrusive thoughts about their anxious autobiographical events. Thus, our results demonstrate that repressive coping might be adaptive in the short run, but counterproductive in the long run.

Adaptation, Psychological↗
PubMed2005

Stress-induced cortisol responses, sex differences, and false recollections in a DRM paradigm.

The current studies investigated whether acute stress potentiates false recollections (so-called "false memories") in a Deese-Roediger-McDermott (DRM) paradigm, and whether sex differences modulate these effects. Participants were assigned to either a stress (trier social stress test) or a control group. Subsequently, they were subjected to DRM word lists and probed for recall and recognition. Results showed no differences between the stress and control group on measures of false recollections (Study 1; N=60). Even though correct recall was impaired by acute stress, there were no differences between high or low cortisol responders and controls on false recall or recognitions rates (Study 2; N=92). These results suggest that cortisol responses do not directly potentiate false recollections. Neither in Study 1 nor in Study 2 did we find any evidence that the effects of cortisol on false recollections are different in men and women, although there was an indication that independent of stress men produced more commission errors.

Adult↗
PubMed2005

Retrieval inhibition of trauma-related words in women reporting repressed or recovered memories of childhood sexual abuse.

Several authors have argued that survivors of childhood sexual abuse (CSA) who report to have repressed their traumatic memories are more skilled in forgetting emotional stimuli than survivors who have always remembered the abuse. The current experiment employed a list-wise directed forgetting task to investigate whether women reporting repressed (n = 16) or recovered (n = 23) memories of CSA are better at forgetting disturbing material, relative to women reporting having always remembered their abuse (n = 55) or reporting no history of abuse (n = 20). We found no support for the hypothesis that women reporting repressed or recovered memories of CSA are especially versed in inhibiting retrieval of trauma-related words. Additional analyses revealed that participants characterized by a repressive coping style did not display a superior retrieval inhibition mechanism for negative material.

Adult↗
PubMed2005

Fear-relevant change detection in spider-fearful and non-fearful participants.

Features of threatening stimuli are proposed to be processed fast and automatically, as they call for immediate attention. Phobic patients typically exhibit these attentional biases for stimuli that are relevant for their particular type of fear. In the present study, it was examined whether a change detection paradigm can be used to study attentional bias for fear-related stimuli. Twenty-five spider-fearful and 25 non-fearful participants were confronted with a series of pictures, in which sometimes a spider gradually appeared, sometimes a fear-irrelevant stimulus appeared, and sometimes no change occurred. Participants had to indicate whenever they noticed a change in the picture. Results showed a pattern of fear-relevant change detection. That is, spider changes were more frequently detected than fear-irrelevant changes, and spider-fearful participants detected more spider changes than non-fearful controls. Further, it was found that high-trait anxious participants did not detect more changes than low-trait anxious participants.

Adult↗
PubMed2005

Confusing thoughts and speech: source monitoring and psychosis.

To explore the idea that deficits in source monitoring may underlie positive symptoms of schizophrenia, the current study compared schizophrenic patients' performance (n=15) on an internal source-monitoring task with that of normal controls (n=15). On the basis of a source-monitoring task in which participants had to recall whether they had verbalized answers or merely thought about these answers, overall source monitoring performance, discrimination index, and response bias were calculated. In addition, participants completed cognitive tests and symptomatology questionnaires. Relative to controls, patients had significantly more difficulties with monitoring their own actions and showed a tendency towards misclassifying imagined thoughts as verbalized thoughts. Source-monitoring performance was related to selective attention, but not to other cognitive domains. No relationship was found between source-monitoring and symptomatology. Failures in internal source monitoring are a prominent feature of schizophrenia, and our results suggest that they form a more enduring characteristic of this disorder than has previously been assumed.

Adult↗
PubMed2005

Fantasy proneness, but not self-reported trauma is related to DRM performance of women reporting recovered memories of childhood sexual abuse.

Extending a strategy previously used by , we administered a neutral and a trauma-related version of the Deese-Roediger-McDermott paradigm to a sample of women reporting recovered (n=23) or repressed memories (n=16) of childhood sexual abuse (CSA), women reporting having always remembered their abuse (n=55), and women reporting no history of abuse (n=20). We found that individuals reporting recovered memories of CSA are more prone than other participants to falsely recalling and recognizing neutral words that were never presented. Moreover, our study is the first to show that this finding even held when trauma-related material was involved. Correlational analyses revealed that fantasy proneness, but not self-reported traumatic experiences and dissociative symptoms were related to false recall and false recognition.

Analysis of Variance↗
PubMed2005

Trying to recollect past events: confidence, beliefs, and memories.

Numerous studies claim to have shown that false memories can be easily created in the laboratory. However, a critical analysis of the methods employed in these studies indicates that many of them do not address memory in the strict sense of the word. Instead, some of these studies assess the confidence that participants have in a fictitious (childhood) event, while others pertain to false beliefs about childhood events. While it is difficult to draw precise demarcation lines, we argue that inflated confidence, false beliefs, and false memories are different phenomena. Keeping the origins of these studies in mind (i.e., people who file lawsuits on the basis of their recovered memories), we propose that a fruitful, but stringent definition of false memories would incorporate their consequences. Thus, we argue that this research domain would profit from studies looking explicitly at whether experimental manipulations intended to implant false memories have overt behavioral consequences.

Attitude↗
PubMed2004

Symptom validity testing of feigned amnesia for a mock crime.

Perpetrators sometimes claim loss of memory for the crimes they have committed. For the neuropsychologist, the veracity of such crime-related amnesia is difficult to assess. The aim of the present study was to investigate whether Symptom Validity Testing (SVT) can be used to detect feigning of crime-related amnesia. Undergraduate students (N = 39) were instructed to commit a mock crime and asked to feign complete amnesia for the event. Subsequently, they were given 25 forced-choice items about the "crime" that were always followed by the correct answer and an equally plausible alternative. To counteract chance performance, test items were intermixed with 25 bogus questions that contained two equally plausible alternatives. Results show that a majority of participants (59%) scored below chance level on the critical items of the SVT. In addition, debriefing interviews showed that understanding the rationale behind the SVT was not related to chance performance. SVT procedures therefore might be helpful in identifying feigned crime-related amnesia.

Adolescent↗