Henry Otgaar

Henry Otgaar
Maastricht University | UM · LINC (Faculty of Law KU Leuven); Section Forensic Psychology, Department of Clinical Psychological Science

PhD, Research professor; Professor of Legal Psychology

About

253
Publications
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4,588
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Publications

Publications (253)
Article
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In three studies, we examined whether beliefs in repressed memory and dissociative amnesia could be changed. Participants provided agreement ratings to statements related to repressed memory and dissociative amnesia. Then, they received a university course which included education on the science of memory. Following this, participants had to re-rat...
Article
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People are often exposed to fake news. Such an exposure to misleading information might lead to false memory creation. We examined whether people can form false memories for COVID-19-related fake news. Furthermore, we investigated which individual factors might predict false memory formation for fake news. In two experiments, we provided participan...
Article
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When beliefs in autobiographical memories are reduced while recollections remain relatively intact, a phenomenon termed nonbelieved memories (NBMs) unfolds. The current preregistered study (N = 104) used a 3-week longitudinal design to investigate the relationships between the frequency of recalled NBMs, memory distrust, rumination over autobiograp...
Article
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People lie on a frequent basis. However, when a victim of maltreatment lies by denying the abuse, lies can become forensically relevant. We have reviewed the relevant literature on the prevalence and memory consequences of such false denials. The way forensic interviewers proceed in the face of denying children will be shaped by their beliefs about...
Article
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Legal psychologists’ assessments can have a major impact on the fact finder’s evaluation of evidence and, consequently, perceptions of guilt. Yet, in the few studies about legal psychologists’ assessments and reports, great variability was found. As is the case with other forensic expert domains, legal psychologists are prone to cognitive biases, s...
Article
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In various countries, forensic scientists have begun to express their expert opinion in terms of the likelihood of observing the evidence under the primary and under an alternative hypothesis (i.e., the likelihood-ratio approach). This development is often confined to technical domains such as fingerprint analyses. In forensic psychological experti...
Article
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In the current experiment, we examined the effects of self‐generated deceptive behavior on memory. Participants (n = 230) were randomly assigned to a “strong‐incentive to cheat” or “weak‐incentive to cheat” condition and played the adapted Sequential Dyadic Die‐Rolling paradigm. Participants in the “strong‐incentive to cheat” condition were incenti...
Article
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Ross (in press) argued that false memory researchers misunderstand the concepts of repression and dissociation, as well as the writings of Freud. In this commentary, we show that Ross is wrong. He oversimplifies and misrepresents the literature on repressed and false memory. We rebut Ross by showing the fallacies underlying his arguments. For examp...
Article
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In the current experiment, we examined the effects of self-generated deceptive behavior on memory. Participants (n = 230) were randomly assigned to a “strong-incentive to cheat” or “weak-incentive to cheat” condition and played the adapted Sequential Dyadic Die-Rolling paradigm. Participants in the “strong-incentive to cheat” condition were incenti...
Article
Full-text available
We examined whether fabrication affects memory using a new paradigm combining the Deese/Roediger-McDermott paradigm (DRM) and the Amsterdam Short Term Memory task (ASTM). Participants were assigned to either a forced fabrication or honest condition, and encoded emotionally-negative and neutral wordlists by reading words out loud. The wordlists cont...
Article
This special issue honours James Ost's (1973-2019) contributions to our understanding of false and distorted remembering. In our editorial, we introduce some of James' distinctive research themes including the experiences of people who retract "recovered" memories, social (e.g., co-witness and interviewer influence) and personality influences on fa...
Article
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We examined the mnemonic effects of falsely denying a self-performed action. Specifically, participants (N = 30) performed, imagined, or received no instruction about 24 action statements (e.g., “cross your arms”). Next, their memory for whether they had performed, imagined, or did nothing (i.e., received no instructions) with these actions was tes...
Article
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False denials are sometimes used to cope with traumatic experiences. We examined whether false denials can affect true and false memory production for a traumatic event and conversations surrounding the trauma. One hundred-twenty-six participants watched a trauma analogue video of a car crash before being randomly asked in a discussion with the exp...
Article
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A suspect of a crime can avoid legal repercussions by creating a false alibi. We examined whether creating such a false alibi can have adverse effects on memory. To do so, participants watched a mock crime video and were either instructed to create a false alibi or to provide an honest account for what they actually saw in the video. After a two-da...
Article
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Pretending to suffer from amnesia for a mock crime has been shown to lead to memory impairments. Specifically, when people are asked to give up their role of simulators, they typically recall fewer crime-relevant details than those who initially confess to a crime. In the current review, we amassed all experimental work on this subject and assessed...
Article
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Are personality traits related to symptom overreporting and/or symptom underreporting? With this question in mind, we evaluated studies from 1979 to 2020 ( k = 55), in which personality traits were linked to scores on stand-alone validity tests, including symptom validity tests (SVTs) and measures of socially desirable responding (SDR) and/or super...
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In a new commentary in Mindfulness , Neff once again tried to defend the use of the Self-Compassion Scale (SCS) total score by arguing that compassionate and uncompassionate self-responding (CS and UCS) are part of a bipolar continuum. In this brief reaction, we refute this notion and also clarify how the continued use of the SCS total score muddie...
Article
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We report on a unique Italian criminal case in which a court ruled that a therapist implanted false memories of abuse in a young girl. Using therapeutic excerpts, we show that the therapist used a multitude of problematic interventions that are all linked to false memory creation. Specifically, an analysis of the therapeutic excerpts showed that ac...
Article
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Victims of abuse might deny their traumatic experiences. We studied mnemonic effects of simulating false denial of a child sexual abuse narrative. Participants (N = 127) read and empathized with the main character of this narrative. Next, half were instructed to falsely deny abuse-related information while others responded honestly in an interview....
Article
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Risk assessment is an essential aspect of child abuse investigations in order to estimate the risk of future abuse and to develop a risk management and intervention plan. According to the risk–need–responsivity model, intervention and risk monitoring needs to target dynamic risk factors to prevent future child maltreatment. In the current study, we...
Article
Language abilities have been heralded as an important cognitive factor driving children’s memory and suggestibility in forensic contexts. To this end, we reviewed over 30 years of child eyewitness memory literature to identify patterns in how language skills affect children’s event memory and suggestibility. Across 37 studies examining 3071 childre...
Article
The entactogen 3,4-Methylenedioxymethamphetamine (MDMA) is increasingly being recognized for its therapeutic potential but is also widespread in nightlife settings where it may co-occur with crime. Since previous research detected impaired verbal memory during acute MDMA intoxication, understanding the drug's ramifications in an applied legal conte...
Article
Objectives The role of self in veridical memory has been extensively studied, but what is the role of self in false memory development across the life span? The current study examined the impact of self-reference on associative false memory in children, younger adults, and older adults, and further investigated possible mechanisms concerning how se...
Article
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Research on the effects of lying and memory is increasingly attracting empirical attention. In the current manuscript, a scientometric analysis was carried out on the mnemonic consequences of lying. This analysis took into account 70 published articles extracted from Scopus and Web of Science databases from 1998 to 2021. A scientometric analysis wa...
Article
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The entactogen 3,4-Methylenedioxymethamphetamine (MDMA) is increasingly being recognized for its therapeutic potential but is also widespread in nightlife settings where it may co-occur with crime. Since previous research detected impaired verbal memory during acute MDMA intoxication, understanding the drug’s ramifications in an applied legal conte...
Article
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Research on memory distrust and nonbelieved memory both stress the importance of belief in memory but no previous research has brought these fields together. In the present study, we examined how trait memory distrust is associated with false memory and nonbelieved memory, self-esteem as well as personality traits. Through two studies (N 1 = 280, N...
Article
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In the present study, we used a new approach to establish the Smallest Effect Size of Interest (SESOI) for false memory research by asking memory researchers what they considered to be the SESOI in false memory research. They were presented with three hypothetical and three influential paper scenarios. These scenarios depicted studies examining the...
Article
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In this registered report, we propose a meta-analysis of laboratory studies that will examine the size of the impact of forced confabulation on false memory formation. To carry out the literature search, we will use the PRISMA workflow and the following databases and repositories: PsycINFO, PsycArticles, all editions of Web of Science Core Collecti...
Preprint
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Temporally structured sequences of experiences, such as narratives or life events, are segmented in memory into discrete situational models. In segmentation, contextual shifts are processed as situational boundaries that temporally cluster items according to the perceived contexts. As such, segmentation enhances associative binding of items within...
Article
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We offer an elegant new and straightforward paradigm to implant false autobiographical memories. Participants received twenty autobiographical events including a critical false event (i.e., swimsuit falling off) and had to indicate whether they ever experienced these events. After 1-week, participants who did not experience the false event received...
Article
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Statements from eyewitnesses can play an essential role in legal cases. However, not all of these statements are based entirely on memories of actual events but may also contain false memories. Determining whether a statement originates from a real event or not is a crucial issue in many legal cases, as psychological expert witnesses are often aske...
Article
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The survival processing advantage refers to the finding that processing information according to its survival value improves memory retention. We used mass-testing across three experiments to examine whether the survival processing advantage could be extended to crime-related contexts when adopting both offender’s (Experiment 1 and 2) and victim’s...
Article
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Memories of the past can guide humans to avoid harm. The logical consequence of this is if memories are changed, avoidance behavior should be affected. More than 80 years of false memory research has shown that people’s memory can be re-constructed or distorted by receiving suggestive false feedback. The current study examined whether manipulating...
Preprint
Since the early work of Cohen (1962) psychological researchers have become aware of the importance of doing a power analysis to ensure that the predicted effect will be detectable with sufficient statistical power. APA guidelines require researchers to provide a justification of the chosen sample size with reference to the expected effect size; an...
Article
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In the Netherlands, there is currently no quality standard for conducting child forensic interviews in Child Protective Services (CPS) . The lack of such standard causes concern regarding the quality of these interviews, which are used to determine the child’s safety and implementing treatment. In the current study, we implemented the National Inst...
Article
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The current study examined the effects of different delivery modes of misinformation on false memory creation in adolescents and adults. Forty adolescents (14-15 year olds) and fifty-three adults (over 18) were instructed to watch a video. Following this, half of the participants were given direct-with interaction misinformation, in which misinform...
Article
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Dissociative amnesia is one of the most controversial categories in the field of psychiatry and clinical psychology. Self-reports of dissociative amnesia in the general population, and beliefs about this topic, have so far not been subjected to empirical scrutiny. Here, we surveyed a sample from the general population (N = 1,017), revealing that ab...
Article
Victims, witnesses, and suspects of crime are frequently intoxicated by Alcohol or Other Drugs (AOD) during the event. How intoxication is perceived by investigating officers, and the manner in which this is handled during interview procedures, can affect the quality of information obtained and therefore investigative outcomes. Various factors are...
Article
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Research to date has exclusively focused on the implantation of false memories for single events. The current experiment is the first proof of concept that false memories can be implanted for repeated autobiographical experiences using an adapted false memory implantation paradigm. We predicted that false memory implantation approaches for repeated...
Article
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In a review of the literature in this journal, Piedfort-Marin et al. (2021) identified what they purported to be myths about dissociative identity disorder (DID) and dissociative amnesia. When responding to these beliefs, they supported the Trauma Model of dissociation and argued for a causal etiological link between trauma and dissociative conditi...
Article
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Does Eye Movement and Desensitization and Reprocessing (EMDR) therapy affect the accuracy of memories? This recurrent issue in recent memory research bears relevance to expert witness work in the courtroom. In this review, we will argue that several crucial aspects of EMDR may be detrimental to memory. First, research has shown that eye movements u...
Article
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Faulty eyewitness testimony can be a notorious source of mistakes in the legal system potentially leading to wrongful convictions and miscarriages of justice. The current study examined the knowledge of a sample of police officers (n = 270) and psychologists (n = 63) in Indonesia regarding factors known to influence the validity of eyewitness testi...
Article
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The present experiment aimed to examine how fabrication can affect memory. In particular, we examined whether different types of fabrication can lead to different mnemonic effects. A sample of 159 participants watched a video of a robbery and subsequently answered some questions about it. Participants were divided into three conditions: one group w...
Article
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Eyewitnesses may experience stress during a crime and when attempting to identify the perpetrator subsequently. Laboratory studies can provide insight into how acute stress at encoding and retrieval affects memory performance. However, previous findings exploring this issue have been mixed. Across two preregistered experiments, we examined the effe...
Article
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The eyewitness and fundamental memory research fields have investigated the effects of acute stress at encoding on memory performance for decades yet results often demonstrate contrasting conclusions. In this review, we first summarize findings on the effects of acute encoding stress on memory performance and discuss how these research fields often...
Article
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This preregistered experiment aimed to investigate the impact of background information regarding an alleged victim of child sexual abuse on police investigators’ perception of the credibility of the victim’s statement, expected case outcome, and the type of questions police investigators plan to ask the victim in an investigative interview. We exp...
Article
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De vraag hoe traumatische ervaringen, zoals seksueel misbruik, worden herinnerd behoort tot een van de meeste verhitte debatten in de psychologie. Het gaat dan met name om de kwestie van verdringing en of traumatische ervaringen onbewust kunnen worden opgeslagen. Otgaar en collega’s laten zien dat het debat hierover aan een stevige opmars bezig is....
Article
Full-text available
The proposed experiment will examine the effect of deceptive behavior on memory. Participants will be assigned to a “strong-incentive to cheat” or “weak-incentive to cheat” condition and play the adapted Sequential Dyadic Die-Rolling paradigm. Specifically, Player A (computer; participants think it is another participant) throws a die and reports i...
Article
Full-text available
Previous studies have found that false memories increase when people receive stimuli which is related to their knowledge base. In the current set of four experiments, we examined how accident experience affected false memory production among motorcyclists using different types of false memory word lists. Specifically, Experiments 1, 2, and 3 were c...
Article
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Dissociative amnesia, defined as an inability to remember important autobiographical experiences usually of a stressful nature, is a controversial phenomenon. We systematically reviewed 128 case studies of dissociative amnesia reported in 60 papers that appeared in peer-reviewed journals in English over the past 20 years (2000-2020). Our aim was to...
Article
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In two studies, we surveyed the beliefs of undergraduate students (Study 1) and the general public (Study 2) about deceptive behavior, memory functioning, and the effects of lying on memory. We compared participants’ beliefs with the current memory and deception literature. Overall, participants in both studies believed that different types of lies...
Article
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The current experiment examined the effect of forewarning on children’s (11 to 12 years of age) and adults’ spontaneous false memory creation by presenting participants with semantically related word lists that are often used to elicit false memories (i.e., Deese- Roediger-McDermott (DRM) paradigm). The forewarning consisted of an explanation of th...
Chapter
Literature review on the assessment of police interviewers – an assessment before enrolling in advanced interview courses in order to save capacity and costs, to enhance successful completion of the course, and to prevent disappointment.
Article
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Recent studies have demonstrated that lying can affect memory and that such memory effects are based on the cognitive load required in performing the lie. The present study aimed to verify whether the impact of two deceptive strategies (i.e., false denials and fabrication) depends on individuals’ cognitive resources in terms of Executive Functions...
Article
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In a preregistered experiment, we examined the efficacy of arousal reappraisal as an intervention for reducing the negative effects of stress at retrieval on memory. Participants (N = 177) were semi-randomly assigned to one of three conditions: a Stress-intervention condition, a Stress-placebo condition, and a No-stress-placebo control condition. P...
Article
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Memory is considered to be a flexible and reconstructive system. However, there is little experimental evidence demonstrating how associations are falsely constructed in memory and even less is known about the role of the self in memory construction. We investigated whether false associations involving non-presented stimuli can be constructed in ep...
Article
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Alcohol and other psychoactive drugs are oftentimes implicated in legal cases. A pertinent question herein is whether such substances might adversely affect testimonies of victims, eyewitnesses, or suspects by propelling the formation of false memory and increasing susceptibility to suggestion. In the current review, we amassed all available eviden...
Article
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Expert witnesses and scholars disagree on whether suggestibility and compliance are related to people’s tendency to falsely confess. Hence, the principal aim of this review was to amass the available evidence on the link between suggestibility and compliance and false confessions. We reviewed experimental data in which false confessions were experi...
Article
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Therapists, judges, law enforcement, and students often believe in the existence of automatic and unconscious repression. Such a belief can be perilous as it might lead therapists to suggestively search for repressed memories leading to false memories. Recovering therapy-induced false memories of criminal acts can have serious consequences. Here, w...
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Objectives Several scholars have questioned the use of the total Self-Compassion Scale (SCS) score as an appropriate index for measuring self-compassion as a protective psychological trait. Methods We present two new studies to further examine the relationships between SCS or SCS-Short Form scores and symptoms of anxiety and depression in non-clin...
Article
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What does science tell us about memory phenomena such as false and repressed memories? This issue is highly pressing as incorrect knowledge about these memory phenomena might contribute to egregious effects in the courtroom such as false accusations of abuse. In the current article, we provide a succinct review of the scientific nature of false and...