Implanting rich autobiographical false memories: Meta–analysis for forensic practice and judicial judgment making

Objective: The implanting of rich autobiographical false memories is crucial for judicial decision–making, and the forensic evaluation of a testimony. In order to assess this issue, a meta–analytical review of the probability of implanting rich autobiographical false memories was performed. Method: A total of 30 primary studies analysing the probability of implanting rich autobiographical false memories were retrieved. Random–effects meta–analyses correcting the effect size for sampling error were performed. Results: The results revealed a significant, positive, generalizable (the lower limit for the 80% credibility value was d = 1.13), and more than large mean effect size (d = 1.43[1.33, 1.53]) for the implanting of false memory. The moderating effects of stimulus type showed that the effect of the probability of implanted false memory was significantly higher in experienced events (d = 2.03[1.63, 2.43]) than in false narratives (d = 1.35[1.23, 1.47]), and in doctored photographs (d = 1.29[1.06, 1.52]). A similar effect for memory implantation was observed in both the underage (d = 1.44[1.29, 1.59]), and in adults (d = 1.36[1.22, 1.50]). The moderator techniques for implanting false memories revealed a significantly lower probability of implanting false rich memory with non–directive instructions (d = 0.90[0.53, 1.27]) than with guided imagery (d = 1.45[1.32, 1.58]), or with pressure to answer (d = 1.56[1.17, 1.95]) instructions. The event emotional valence moderator exhibited the same effect for positive (d = 1.27[1.09, 1.45]) and negative valence events (d = 1.30[1.17, 1.43]). Conclusions: The implications of the results for forensic testimony evaluation, police interrogations, and judicial cross–examination are discussed. (AU)

Recovered memories of trauma as a special (or not so special) form of involuntary autobiographical memories.

Recovered memories of trauma are memories of traumatic events experienced generally during childhood, but of which the persons were unaware until they retrieved it. Legal decisions are sometimes based on such recovered memories, the validity of which is often questioned. Yet, people can recover genuine traumatic memories of childhood abuse. In this paper, we present and further discuss the idea that recovered traumatic memories can be interpreted in the context of the autobiographical memory framework. Specifically, we argue that recovered memories may be accessed after exposure to incidental cues that initiate unexpected spontaneous memory retrieval. Thus, we relate the recovered memory phenomenon to involuntary autobiographical memories and argue that it is an example of highly stressful, emotionally negative, and intense involuntary memories that were yet never recalled. This novel, evidence-based perspective leads us to reconsider the examination of the validity of eyewitness testimony as a continuum ranging from the least valid form (i.e., memories recovered in highly suggestive context facilitating its factitious reconstruction) to the most valid form (i.e., memories that were triggered by cues without any person's voluntary engagement), and this in relation with how internal (e.g., age and internal cue) or external (e.g., suggestion in therapy, suggestion during investigative interview, and contextual cue) factors may influence memory retrieval. Finally, we propose several recommendations for experts that may be useful in assessing the validity of a testimony based on recovered memories.

Suppression and Memory for Childhood Traumatic Events: Trauma Symptoms and Non-Disclosure.

Self-reported lost memory of child sexual abuse (CSA) can be mistaken for "repressed memory." Based on our longitudinal studies of memory and disclosure in child maltreatment victims who are now adults, we discuss findings relevant to "repressed memory cases." We examined relations between self-report of temporarily lost memory of CSA (subjective forgetting) and memory accuracy for maltreatment-related experiences (objective memory). Across two studies involving separate samples, we find evidence for memory suppression rather than repression: (1) Most adults who claimed temporary lost memory of CSA reported memory suppression and clarified that they could have remembered the event if asked; (2) subjective forgetting was positively associated with accurate objective memory for maltreatment-related experiences. Subjective forgetting was also related to increased adult trauma symptoms and related to childhood non-disclosure of CSA. Moreover, trauma-related psychopathology mediated the relation between non-disclosure and subjective forgetting. Implications for psychological theory and repressed memory cases are discussed.

Implanting rich autobiographical false memories: Meta-analysis for forensic practice and judicial judgment making.

Objective: The implanting of rich autobiographical false memories is crucial for judicial decision-making, and the forensic evaluation of a testimony. In order to assess this issue, a meta-analytical review of the probability of implanting rich autobiographical false memories was performed. Method: A total of 30 primary studies analysing the probability of implanting rich autobiographical false memories were retrieved. Random-effects meta-analyses correcting the effect size for sampling error were performed. Results: The results revealed a significant, positive, generalizable (the lower limit for the 80% credibility value was d = 1.13), and more than large mean effect size (d = 1.43[1.33, 1.53]) for the implanting of false memory. The moderating effects of stimulus type showed that the effect of the probability of implanted false memory was significantly higher in experienced events (d = 2.03[1.63, 2.43]) than in false narratives (d = 1.35[1.23, 1.47]), and in doctored photographs (d = 1.29[1.06, 1.52]). A similar effect for memory implantation was observed in both the underage (d = 1.44[1.29, 1.59]), and in adults (d = 1.36[1.22, 1.50]). The moderator techniques for implanting false memories revealed a significantly lower probability of implanting false rich memory with non-directive instructions (d = 0.90[0.53, 1.27]) than with guided imagery (d = 1.45[1.32, 1.58]), or with pressure to answer (d = 1.56[1.17, 1.95]) instructions. The event emotional valence moderator exhibited the same effect for positive (d = 1.27[1.09, 1.45]) and negative valence events (d = 1.30[1.17, 1.43]). Conclusions: The implications of the results for forensic testimony evaluation, police interrogations, and judicial cross-examination are discussed.

Reports of Recovered Memories in Therapy in Undergraduate Students.

Psychologists have debated the wisdom of recovering traumatic memories in therapy that were previously unknown to the client, with some concerns over accuracy and memory distortions. The current study surveyed a sample of 576 undergraduates in the south of the United States. Of 188 who reported attending therapy or counselling, 8% reported coming to remember memories of abuse, without any prior recollection of that abuse before therapy. Of those who reported recovered memories, 60% cut off contact with some of their family. Within those who received therapy, those who had a therapist discuss the possibility of repressed memory were 28.6 times more likely to report recovered memories, compared to those who received therapy without such discussion. These findings mirror a previous survey of US adults and suggest attempts to recover repressed memories in therapy may continue in the forthcoming generation of adults.

What do people really think of when they claim to believe in repressed memory? Methodological middle ground and applied issues.

What do people really think of when they say they believe in repressed traumatic memory? In two studies (NStudy 1 = 3158; NStudy 2 = 305) using an integrative method taking into account recent methodological discussions, we found that, in total, 2458 participants (71% of the two combined samples) reported that they believed in repressed memory. In Study 1, based on separate questions on the whole group, we found 71% of agreement with the concept of repression, 74% with the concept of unconscious repression, and 54% with the concept of deliberate memory suppression. Participants with no memory of childhood abuse endorsed unconscious and deliberate mechanisms less than those with such memories. In Study 2, the order in which the items were presented was not associated with the beliefs in the different statements. Overall, our results show that people see repression as an unconscious mechanism. We suggest the use of within-subject designs and/or follow-up questions to determine how people understand the concept of repression. Such adherence to this controversial concept can have adverse implications in the clinical and legal arenas.

The acute effects of classic psychedelics on memory in humans.

RATIONALE: Memory plays a central role in the psychedelic experience. The spontaneous recall and immersive reliving of autobiographical memories has frequently been noted by researchers and clinicians as a salient phenomenon in the profile of subjective effects of classic psychedelic drugs such as psilocybin, LSD, and ayahuasca. The ability for psychedelics to provoke vivid memories has been considered important to their clinical efficacy. OBJECTIVE: This review aims to examine and aggregate the findings from experimental, observational, and qualitative studies on the acute modulation of memory by classic psychedelics in humans. METHOD: A literature search was conducted using PubMed and PsycInfo as well as manual review of references from eligible studies. Publications reporting quantitative and/or qualitative findings were included; animal studies and case reports were excluded. RESULTS: Classic psychedelics produce dose-dependently increasing impairments in memory task performance, such that low doses produce no impairment and higher doses produce increasing levels of impairment. This pattern has been observed in tasks assessing spatial and verbal working memory, semantic memory, and non-autobiographical episodic memory. Such impairments may be less pronounced among experienced psychedelic users. Classic psychedelics also increase the vividness of autobiographical memories and frequently stimulate the recall and/or re-experiencing of autobiographical memories, often memories that are affectively intense (positively or negatively valenced) and that had been avoided and/or forgotten prior to the experience. CONCLUSIONS: Classic psychedelics dose-dependently impair memory task performance but may enhance autobiographical memory. These findings are relevant to the understanding of psychological mechanisms of action of psychedelic-assisted psychotherapy.

The Return of the Repressed: The Persistent and Problematic Claims of Long-Forgotten Trauma.

Can purely psychological trauma lead to a complete blockage of autobiographical memories? This long-standing question about the existence of repressed memories has been at the heart of one of the most heated debates in modern psychology. These so-called memory wars originated in the 1990s, and many scholars have assumed that they are over. We demonstrate that this assumption is incorrect and that the controversial issue of repressed memories is alive and well and may even be on the rise. We review converging research and data from legal cases indicating that the topic of repressed memories remains active in clinical, legal, and academic settings. We show that the belief in repressed memories occurs on a nontrivial scale (58%) and appears to have increased among clinical psychologists since the 1990s. We also demonstrate that the scientifically controversial concept of dissociative amnesia, which we argue is a substitute term for memory repression, has gained in popularity. Finally, we review work on the adverse side effects of certain psychotherapeutic techniques, some of which may be linked to the recovery of repressed memories. The memory wars have not vanished. They have continued to endure and contribute to potentially damaging consequences in clinical, legal, and academic contexts.

Reports of recovered memories of childhood abuse in therapy in France.

Recovered memories of abuse in therapy are especially controversial if the clients were not aware they were abused before therapy. In the past, such memory recovery has led to legal action, as well as a debate about whether such memories might be repressed, forgotten, or false memories. More than two decades after the height of the controversy, it is unclear to what degree such memories are still recovered today, and to what extent it occurs in France. In our French survey of 1312 participants (Mage = 33; 53% female), 551 reported having done therapy at some point. Of that 551, 33 (6%) indicated they had recovered memories of abuse in therapy that they did not know about before therapy. Sexual abuse was the most commonly reported type that was recovered in therapy (79%). As in past research, discussing the possibility of repressed memories with therapists was associated with reports of recovered memories of abuse. Surprisingly, memory recovery occurred just as much in behavioural and cognitive therapies as it did in therapies focused on trauma. We found recovered memories in a proportion of clients who began therapy recently. Recovered memories in therapy appears to be an ongoing concern in France.

Phenomenological characteristics of recovered memory in nonclinical individuals.

A central hypothesis of recovered memory is that the source of the memory may be misattributed, and the memory of an imagined event may be mistaken as the memory of the perceived event that was not remembered. The judgment of memory source depends upon phenomenological characteristics. Thus, the present study investigated characteristics of recovered memory. To exclude potential confounding effects of traumatic stress and acute mental illness, data on recovered memories of diverse valences in a nonclinical sample were collected. Self-report scales including a measure of memory characteristics were used to evaluate recovered memories and age-matched autobiographical memories that had been continuously remembered. The results showed that recovered memory was of lower clarity and contained less detailed sensory, contextual, and temporal information; additionally, it was associated with fewer thoughts and lower intensity of feelings. Participants also felt less confident regarding the veracity of recovered memory in comparison with continuous memory. In contrast to recovered trauma memory reported by clinical clients, vivid sensory details and intense affect did not characterize recovered memory in nonclinical individuals. The reduction in perceptual and contextual information, as well as cognitive operations, may increase the difficulty of judging the source of recovered memory.