Henry Otgaar

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

The recommendations of this white paper are jointly drafted by researchers in childinterviewing active within the European Association of Psychology and Law and are focusedon cases in which children are interviewed in forensic settings, in particular withininvestigations of child sexual and/or physical abuse.

Purpose This study aimed to examine beliefs in repressed memory and dissociative amnesia from a cross-cultural perspective. Design/methodology/approach Chinese ( n = 123) and Belgian student participants ( n = 270) received several statements tapping into various dimensions of repressed memory and dissociative amnesia. Participants provided belief...

Purpose The purpose of this study was to investigate cognitive behavior therapists and trainees’s beliefs about various aspects of traumatic memory and to investigate cognitive behavior therapists’ practices in relation to alleged traumatic experiences and whether they are linked with their beliefs about various aspects of traumatic memory. Design...

In legal cases, testimonies can become contaminated because of an amalgam of external and internal influences on memory. It is well-established that external influences can hurt memory (e.g., suggestive interviews). However, less focus has been placed on the impact of internal influences (e.g., lying) on memory. In the current review, we show that...

The present review addressed the relationship between two self-related concepts that are assumed to play a role in human resilience and well-being: self-esteem and self-compassion. Besides a theoretical exploration of both concepts, a meta-analysis (k = 76, N = 35,537 participants) was conducted to examine the magnitude of the relation between self...

People differ in their skepticism toward their own memories, which is called memory distrust and is measured by the Squire Subjective Memory Questionnaire (SSMQ) and the Memory Distrust Scale (MDS). In Study 1 (N = 458), we translated the MDS into Chinese and found that MDS scores were correlated with self-reported memory errors, compliance, and li...

The use of alternative scenarios has been advocated as a method to mitigate bias when evaluating the reliability of testimonies. In two experiments, undergraduate students acted as expert witnesses when reading an alleged child sexual abuse case file and evaluated the reliability of the statements. In the first experiment, a subgroup of participant...

Studies have shown that lying can detrimentally affect memory. For example, when people fabricate a false account, this fabrication can turn into a false memory. The current experiment aimed to examine whether the typical effects on memory due to fabrication depend on psychopathy traits. 232 participants completed the Personality Psychopathy Invent...

When memories of past rewarding experiences are distorted, are relevant decision-making preferences impacted? Although recent research has demonstrated the important role of episodic memory in value-based decision-making, very few have examined the role of false memory in guiding novel decision-making. The current study combined the pictorial Deese...

Memories that can be recalled but are no longer believed are termed nonbelieved memories. The current studies examined the creation of emotionally-negative nonbelieved memories after viewing negatively valenced pictures. In both experiments, participants took part in two sessions. In Session 1, after being presented with a set of neutral and negati...

Recent work suggests that the debate surrounding repressed memory and traumatic forgetting continues today. To further investigate this debate, we performed preregistered scientometric analyses on publications on the debate about repressed memory to provide information about its bibliometric evolution. Furthermore, we reviewed these publications to...

The current study examined the effect of reducing beliefs in the occurrence of traumatic experiences on the production of intrusive memories and the memory amplification effect. Participants took part in two sessions. In the first session, participants rated their emotional state before and after viewing trauma-inducing videos. Then, participants c...

When choosing strategies for verifying one’s memory, people are more influenced by the perceived cost of using a strategy than by its likelihood of yielding reliable information (i.e., cheap-strategy bias). The current preregistered study investigated whether people with high memory distrust are less likely to exhibit this bias than their low memor...

Posttraumatic stress disorder (PTSD) is one of the most serious and incapacitating mental diseases that can result from trauma exposure. However, despite its relevance, there is still considerable confusion and debate surrounding its diagnosis. The aim of this umbrella review is to clarify the overall prevalence of PTSD. Furthermore, the study exam...

Background: Legal cases and research have shown that due to suggestive therapeutic interventions, people can start to remember abuse that they never experienced. Some of these people eventually retract their claims of abuse. This study examined the memory reports of self-defined retractors of abuse and the prevalence of nonbelieved memories. Method...

Purpose: A heated debate exists on whether traumatic memories can be dissociated or repressed. One way in which researchers have attempted to prove the existence of dissociative amnesia or repressed memory is to examine whether claims of amnesia for traumatic events are associated with specific neural markers. Methods: Here, we will argue that suc...

When experiencing mental health challenges, we all deserve treatments that actually work. Whether you are a healthcare consumer, student, or mental health professional, this book will help you recognize implausible, ineffective, and even harmful therapy practices while also considering recent controversies. Research-supported interventions are iden...

When experiencing mental health challenges, we all deserve treatments that actually work. Whether you are a healthcare consumer, student, or mental health professional, this book will help you recognize implausible, ineffective, and even harmful therapy practices while also considering recent controversies. Research-supported interventions are iden...

In this commentary, we argue that besides focusing on generalization, sufficient attention must be invested in the practical relevance of psychological and applied memory research. That is, memory research is frequently used to address real life questions. In the area of psychology and law, memory scientists are sometimes asked by court to provide...

Objective: Previous research has indicated high rates of sexual assault (SA) among US students (> 25%). Yet this type of investigation has been less frequent at European universities. Methods: We conducted an investigation at three universities, two Dutch universities (N = 95 and N = 305) and one university in Belgium (N = 307). Students were as...

When choosing strategies for verifying one’s memory, people are more influenced by the perceived cost of using a strategy than by its likelihood of yielding reliable information (i.e., cheap-strategy bias). The current preregistered study investigated whether people with high memory distrust are less likely to exhibit this bias than their low memor...

During police investigations, interviewees are sometimes forced to confabulate a response to questions for which they don't know the answer. In this registered report, we conducted a three-level meta-analysis to examine whether forcing people to confabulate an answer to these questions can lead to false memories for the confabulated details and/or...

Scott O. Lilienfeld was among the most influential clinical psychological scientists, avid promoters of psychological science, and stalwart and effective critics of pseudoscience in our time. We describe the role that Lilienfeld and other skeptical scientists played in the so-called “memory wars” that spanned more than three decades and continue to...

Psychotherapy aims to make patients better. As is true for any type of treatment, psychotherapy regularly fails to achieve this goal. Therapeutic failures may take many forms, and the list of possible reasons for failure is similarly extensive. As we will explain in this chapter, there is no conclusive definition of psychotherapeutic failure. Also,...

Background and purpose: Self-compassion is considered as a protective psychological construct that would shield against the development of emotional problems. The aim of the present study was to compare the 'protective nature' of two measures of self-compassion: the Self-Compassion Scale for Youth (SCS-Y) and the Sussex-Oxford Compassion for the S...

Memory experts are sometimes asked to evaluate the validity of accounts of witnesses, victims, or suspects. In some of these cases, they are asked what effect alcohol has on the validity of such accounts. In this article, we offer a guide on what expert witnesses can reliably say about how alcohol affects memory. We do so by resorting to effect siz...

People who are confronted with criminal situations sometimes lie by using different deceptive strategies. If they eventually come forward with the truth, it is important to understand whether their memory-based testimonies might be affected by their initial lies. To examine and compare the effects of various deceptive strategies (i.e., fabrication,...

Individuals scoring high on psychopathic personality traits process emotional material to a different extent than individuals with few psychopathic traits. Evidence exists that these individuals have impaired emotional memory. The question arises whether this emotional memory impairment has ramifications for the production of emotional false memori...

Psychologists are sometimes asked to provide their expert opinion in court on whether memories of victims, witnesses, or suspects are reliable or not. In this article, we will discuss what expert witnesses can reliably say about memory in the legal arena. We argue that before research on memory can be discussed in legal cases, this research should...

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...

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...

In menig misdaadserie komt het voorbij: de forensisch expert in een witte jas die een vingerspoor in de computer invoert. Al snel komt de computer met de verlossende boodschap: er is een match. Het vingerspoor van de plaats delict komt overeen met de vingerafdruk van de verdachte. Hoera, de zaak is opgelost. Toch? Werkt het inderdaad zo in de prakt...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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....

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...

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...

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...

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...

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...

Samenvatting Over nadelige effecten van psychotherapie is weinig bekend. Dit komt omdat negatieve reacties op psychologische interventies niet standaard worden geregistreerd in psychotherapie-trials. Deze studie beoogt meer inzicht krijgen in de potentieel negatieve effecten van psychotherapie, zoals gerapporteerd door patiënten. Deelnemers werden...

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...

The pursuit of justice increasingly relies on productive interactions between witnesses and investigators from diverse cultural backgrounds during investigative interviews. To date, the role of cultural context has largely been ignored by researchers in the field of investigative interviewing, despite repeated requests from practitioners and policy...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...