Myths of trauma memory: on the oversimplification of effects of attention narrowing under stress.

The present article addresses claims commonly made by prosecution witnesses in sexual assault trials: that attention narrows under stress, and that these attended aspects of the event are encoded in a way that ensures accuracy and resistance to fading and distortion. We provide evidence to contradict such claims. Given that what is encoded is largely the gist of one's interpretation of experience, we discuss the way in which attention and emotion can bias the interpretation of experience. We illustrate with issues of memory reports in cases of acquaintance rape, where the primary issue is the presence or absence of consent. We provide some specific illustrations concerning effects of emotion on interpretation of sexual consent. Finally, based on what is known regarding priming effects on memory retrieval and judgment, we conclude with discussion of the potential of some "trauma-informed" interviewing strategies to promote false memories (such as FETI: Forensic Experiential Trauma Interview).

If you express it in the form of a negation, you can expect an effect similar to misinformation.

The primary goal of the presented research was to investigate how processing post-event information affects memory of details in an event viewed on video. We used two forms of post-event information: classic misinformation (changing or implanting new information into memory) and a new form that involves a correct explicit or implicit negation of the existence of an object in the video. We followed the three-step procedure used in studies on the misinformation effect, with a final memory test that was either immediate or delayed by a week and consisted in indicating which objects appeared in the video. We replicated the misinformation effect. More importantly, in the delayed test condition, both explicitly and implicitly negated objects were falsely recalled more often than unmentioned objects. These results indicate that it is possible to induce negation-related false memories; they also show that memory is impaired by negated post-event information or misleading post-event information.

Normative developmental vs. reverse developmental trends in memory distortion: a framework to investigate the impact of internal and external influences on memory and their relevance to legal decisions.

There are two opposing positions regarding the development of memory: the normative developmental position, and the reverse developmental position. The normative position, which has long been the default presupposition, supports the notion that susceptibility to memory distortion, including false memories, decreases with age. In contrast, the concept of "developmental reversals" supports the notion that susceptibility to memory distortion and false memories increases with age. Each perspective finds support from existing theories as well as from research on endogenous and exogenous sources of influence. In a legal context, having an accurate understanding of the developmental course of false memory can contribute on the one hand to mitigating wrongful convictions and, on the other hand, to appreciating the accuracy of children's statements when warranted. This review aims to integrate the existing literature regarding these seemingly opposite developmental courses and construct a framework outlining the conditions under which we may observe one age trend over the other. This entails an examination of the paradigms that have been invoked to support these competing positions, specifically developmental responses to internal vs. external sources of distortion.

Perceptual comparisons modulate memory biases induced by new visual inputs.

It is well-established that stimulus-specific information in visual working memory (VWM) can be systematically biased by new perceptual inputs. These memory biases are commonly attributed to interference that arises when perceptual inputs are physically similar to VWM contents. However, recent work has suggested that explicitly comparing the similarity between VWM contents and new perceptual inputs modulates the size of memory biases above and beyond stimulus-driven effects. Here, we sought to directly investigate this modulation hypothesis by comparing the size of memory biases following explicit comparisons to those induced when new perceptual inputs are ignored (Experiment 1) or maintained in VWM alongside target information (Experiment 2). We found that VWM reports showed larger attraction biases following explicit perceptual comparisons than when new perceptual inputs were ignored or maintained in VWM. An analysis of participants' perceptual comparisons revealed that memory biases were amplified after perceptual inputs were endorsed as similar-but not dissimilar-to one's VWM representation. These patterns were found to persist even after accounting for variability in the physical similarity between the target and perceptual stimuli across trials, as well as the baseline memory precision between the distinct task demands. Together, these findings illustrate a causal role of perceptual comparisons in modulating naturally-occurring memory biases.

Perceived Distance Alters Memory for Scene Boundaries.

Memory often fills in what is not there. A striking example of this is boundary extension, whereby observers mistakenly recall a view that extends beyond what was seen. However, not all visual memories extend in this way, which suggests that this process depends on specific scene properties. What factors determine when visual memories will include details that go beyond perceptual experience? Here, seven experiments (N = 1,100 adults) explored whether spatial scale-specifically, perceived viewing distance-drives boundary extension. We created fake miniatures by exploiting tilt shift, a photographic effect that selectively reduces perceived distance while preserving other scene properties (e.g., making a distant railway appear like a model train). Fake miniaturization increased boundary extension for otherwise identical scenes: Participants who performed a scene-memory task misremembered fake-miniaturized views as farther away than they actually were. This effect went beyond low-level image changes and generalized to a completely different distance manipulation. Thus, visual memory is modulated by the spatial scale at which the environment is viewed.

False remembering in real life: James Ost's contributions to memory psychology.

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 false remembering, the nature of false remembering itself (e.g., different types of false memories; false memories vs. false beliefs), public understanding of (false) memory, and a historical link to the work of Frederic Bartlett. We illustrate these themes through a number of key publications. The unifying thread behind James' work is his core interest in false/distorted remembering in real-life (typically high-stake) situations, in line with his engagement with the British False Memory Society and his role as an expert witness in court trials. The articles included in this special issue elaborate on the research themes to which James devoted his career and his curiosity.

Vigorous-intensity acute exercise during encoding can reduce levels of episodic and false memory.

The potential benefits (veridical memory) and, importantly, costs (false memory) of acute exercise on memory in conjunction with the timing and type of exercise have not been fully studied. In Experiment 1, we employed a three-condition (15-minute vigorous-intensity acute exercise Before or During memory encoding, or a Control condition of watching a video), within-subjects, counterbalanced design. The procedures included an immediate and delayed (20-minute post encoding) free recall assessment. Veridical memory was determined by the number of studied words that were recalled, whereas false memory was determined by retrieving a non-presented, critical item. For veridical memory, Before was not different than Control (p = .42), however, During was worse than Before and Control (p's < .001). No differences occurred for false memory. Experiment 2 was conducted that included several additional exercise conditions (e.g., light-intensity exercise) during memory encoding, used a recognition task instead of a free recall task, and extended the long-term memory assessment out to 24-hours. Experiment 2 demonstrated that vigorous-intensity acute exercise during encoding reduced both veridical and false memory for related new items (p < .05). These findings demonstrate that the timing and intensity of exercise play an important role in influencing memory performance.

Working Memory Content Is Distorted by Its Use in Perceptual Comparisons.

Visual information around us is rarely static. To perform a task in such a dynamic environment, we often have to compare current visual input with our working memory (WM) representation of the immediate past. However, little is known about what happens to a WM representation when it is compared with perceptual input. To test this, we asked young adults (N = 170 total in three experiments) to compare a new visual input with a WM representation prior to reporting the WM representation. We found that the perceptual comparison biased the WM report, especially when the input was subjectively similar to the WM representation. Furthermore, using computational modeling and individual-differences analyses, we found that this similarity-induced memory bias was driven by representational integration, rather than incidental confusion, between the WM representation and subjectively similar input. Together, our findings highlight a novel source of WM distortion and suggest a general mechanism that determines how WM interacts with new visual input.

Long-term memory interference is resolved via repulsion and precision along diagnostic memory dimensions.

When memories share similar features, this can lead to interference, and ultimately forgetting. With experience, however, interference can be resolved. This raises the important question of how memories change, with experience, to minimize interference. Intuitively, interference might be minimized by increasing the precision and accuracy of memories. However, recent evidence suggests a potentially adaptive role for memory distortions. Namely, similarity can trigger exaggerations of subtle differences between memories (repulsion). Here, we tested whether repulsion specifically occurs on feature dimensions along which memories compete and whether repulsion is predictive of reduced memory interference. To test these ideas, we developed synthetic faces in a two-dimensional face space (affect and gender). This allowed us to precisely manipulate similarity between faces and the feature dimension along which faces differed. In three experiments, participants learned to associate faces with unique cue words. Associative memory tests confirmed that when faces were similar (face pairmates), this produced interference. Using a continuous face reconstruction task, we found two changes in face memory that preferentially occurred along the feature dimension that was "diagnostic" of the difference between face pairmates: (1) there was a bias to remember pairmates with exaggerated differences (repulsion) and (2) there was an increase in the precision of feature memory. Critically, repulsion and precision were each associated with reduced associative memory interference, but these were statistically dissociable contributions. Collectively, our findings reveal that similarity between memories triggers dissociable, experience-dependent changes that serve an adaptive role in reducing interference.

Melting Ice With Your Mind: Representational Momentum for Physical States.

When a log burns, it transforms from a block of wood into a pile of ash. Such state changes are among the most dramatic ways objects change, going beyond mere changes of position or orientation. How does the mind represent changes of state? A foundational result in visual cognition is that memory extrapolates the positions of moving objects-a distortion called representational momentum. Here, five experiments (N = 400 adults) exploited this phenomenon to investigate mental representations in state space. Participants who viewed objects undergoing state changes (e.g., ice melting, logs burning, or grapes shriveling) remembered them as more changed (e.g., more melted, burned, or shriveled) than they actually were. This pattern extended to several types of state changes, went beyond their low-level properties, and even adhered to their natural trajectories in state space. Thus, mental representations of objects actively incorporate how they change-not only in their relation to their environment, but also in their essential qualities.

Cross-examination may be more detrimental to repeated-event children than single-event children.

Cross-examination is detrimental to the consistency and accuracy of children's reports and a re-direct interview may rehabilitate accuracy. We compared the effects of cross-examination on reports provided by single-event and repeated-event children. Children participated in one or five magic shows. One week later they were interviewed in a supportive manner (Interview 1). Next, a different interviewer cross-examined half the children or asked the other children all questions again (Interview 2). Finally, the initial interviewer re-directed the children by re-asking questions in a supportive manner (Interview 3). When defined narrowly (the instance children were asked to describe), cross-examination was more detrimental to single-event children and the re-direct interview rehabilitated correct responses for all children. When defined broadly (experienced details), cross-examination was more detrimental to repeated-event children and the re-direct did not rehabilitate correct responses for repeated-event children. Therefore when performance was off the floor, cross-examination was more detrimental to repeated-event children. The changes that repeated-event children make under cross-examination are explained by cognitive factors and social influences Ost et al., [2016]. Recall, verbatim memory and remembered narratives. In G. Oxburgh (Ed.), Communication in investigative and legal contexts: Integrated approaches from forensic psychology, linguistics and law enforcement (pp. 39-54). Wiley Blackwell).

How deception and believability feedback affect recall.

While research suggests that telling lies can distort memory for the truth, the effects of receiving feedback about the believability about one's lies are not known. We hypothesised that participants who exaggerated the number of stolen items (vs. told the truth) in a mock insurance claim and then received feedback that their statement was believable (vs. not believable) would incorporate this lie into memory. In a two-phase between-subjects design, participants saw images of an office pre- and post-theft and were randomly assigned to report the number of stolen items accurately (truth-tellers) or exaggerate (liars). They were then randomly assigned to receive feedback that their statement was believable or not. Approximately two weeks later, participants' recall of the theft was measured. Liars and truth-tellers recalled a similar number of stolen items, but liars had less accurate recall for exactly which items were stolen. Liars (vs. truth-tellers) also made more omission errors. The majority of participants who fabricated additional stolen items (65.7%) incorporated one or more of these (false) items into their memory. Results suggest that source monitoring errors may lead fabricated details to be incorporated into memory. Although no effects of believability feedback were observed, recommendations for future researchers are discussed.

Are observer memories (accurate) memories? Insights from experimental philosophy.

A striking feature of our memories of the personal past is that they involve different visual perspectives: one sometimes recalls past events from one's original point of view (a field perspective), but one sometimes recalls them from an external point of view (an observer perspective). In philosophy, observer memories are often seen as being less than fully genuine and as being necessarily false or distorted. This paper looks at whether laypeople share the standard philosophical view by applying the methods of experimental philosophy. We report the results of five studies suggesting that, while participants clearly categorize both field and observer memories as memories, they tend to judge that observer memories are slightly less accurate than field memories. Our results suggest, however, that in lay thought, the difference between field and observer memories is not nearly as clear-cut as philosophers have generally taken it to be.

Linking creativity and false memory: Common consequences of a flexible memory system.

Episodic retrieval plays a functional-adaptive role in supporting divergent thinking, the ability to creatively combine different pieces of information. However, the same constructive memory process that provides a functional-adaptive benefit can also leave memory prone to error. In two experiments, we employed an individual differences approach to examine the relationship between different forms of creative thinking (divergent and convergent thinking) and false memory generation in the Deese-Roediger-McDermott paradigm. In Experiment 1, and replicating prior findings, false recognition was significantly predicted by convergent thinking performance. Critically, we also observed a novel predictive relationship between false recognition and quantitative metrics of divergent thinking performance. In Experiment 2, these findings were replicated and we further showed that false recall was predicted by quantitative metrics of divergent thinking. Our findings suggest that constructive memory processes link creative thinking with the production of memory errors.

Deepfake false memories.

Machine-learning has enabled the creation of "deepfake videos"; highly-realistic footage that features a person saying or doing something they never did. In recent years, this technology has become more widespread and various apps now allow an average social-media user to create a deepfake video which can be shared online. There are concerns about how this may distort memory for public events, but to date no evidence to support this. Across two experiments, we presented participants (N = 682) with fake news stories in the format of text, text with a photograph or text with a deepfake video. Though participants rated the deepfake videos as convincing, dangerous, and unethical, and some participants did report false memories after viewing deepfakes, the deepfake video format did not consistently increase false memory rates relative to the text-only or text-with-photograph conditions. Further research is needed, but the current findings suggest that while deepfake videos can distort memory for public events, they may not always be more effective than simple misleading text.

Understanding Older Adults' Memory Distortion in the Light of Stereotype Threat.

Numerous studies have documented the detrimental impact of age-based stereotype threat (ABST) on older adults' cognitive performance and especially on veridical memory. However, far fewer studies have investigated the impact of ABST on older adults' memory distortion. Here, we review the subset of research examining memory distortion and provide evidence for the role of stereotype threat as a powerful socio-emotional factor that impacts age-related susceptibility to memory distortion. In this review we define memory distortion as errors in memory that are associated with gist-based errors or source misattributions. Whereas, some of the reviewed experiments support the conclusion that ABST should be considered in the context of age-related differences in memory distortion, others reported little or no impact of stereotype threat. These discrepancies suggest that the role of ABST, and socio-emotional processes generally, in age-related changes in memory distortion are less clear. In this review, we argue that ABST does play an important role in age-related changes in memory distortion. We present evidence suggesting that discrepancies in the reviewed literature may be reconciled when evaluated in the context of the leading theories about stereotype threat: the Executive Resource Depletion hypothesis and the Regulatory Focus theory. We also discuss how differences in methodology and participant characteristics can account for a priori contradictory results in the literature. Finally, we propose some recommendations for researchers and practitioners when assessing memory in older adults.

Maladaptive Properties of Context-Impoverished Memories.

The context in which sudden fearful events occur can be poorly encoded into memory. Yet, the consequences of the resulting context-impoverished memories remain unknown. We demonstrate that restricting the time available for context encoding during contextual fear conditioning causes maladaptively overgeneralized and inextinguishable fear. However, post-conditioning context exposure enables further context encoding through hippocampal reconsolidation-dependent memory updating. Updating in the conditioning context alleviates overgeneralization and restores capacity for extinction. However, updating in a similar safe context erroneously shifts fear from the dangerous to the safe context. We argue that these phenomena can be explained by uncertainty about where events occurred. Moreover, we show that a hippocampal-neocortical neurocomputational model based on this assumption successfully simulates and explains our observations. These findings reveal that context-impoverished memories are maladaptive and can be improved or distorted after recall, with implications for basic memory theory, memory distortion, and treatment of disorders like post-traumatic stress disorder.

The base rate neglect in episodic memory.

The main objective of the present research was, for the first time, to assess a potential similarity in the representational bases for the base rate neglect in memory versus conditional probability judgment. Participants learned target and filler words, each of which was presented on a separate list (List 1 or List 2) and in a distinct colour (red or blue), with a manipulation of different base rates for these list and colour categories. During recognition tests, participants made prior and posterior episodic judgments (e.g., "What colour was the word?", "Given that the word was in red, on which list was the word?") on the target words, which respectively parallel independent and conditional probability assessments that figure in Bayes' theorem. The results implied that biased prior and posterior judgments presumably cause the base rate neglect, inasmuch as the prior cue of a low (high) base rate is likely to lead to a bias toward retrieving high (low) base rate posterior evidence. There was also a finding showing that memory analogues of probability estimates reflect the base rate neglect in both low and high base rate categories, but is presumably stronger with posterior judgment of Colour|List than List|Colour relative to the high base rate category.

Acute Exercise on Memory Reconsolidation.

BACKGROUND AND OBJECTIVE: Once a memory is reactivated, it enters a labile state and, thus, is vulnerable to memory decay and/or distortion. Recent research demonstrates that acute, high-intensity exercise is associated with enhanced episodic memory function. Very limited research, however, has evaluated whether acute exercise can attenuate memory distortion from memory reactivation, which was the purpose of this study. METHODS: A between-subject randomized controlled intervention was employed. Participants (N = 80) were randomly assigned to one of four groups, including (1) reminder with exercise, (2) reminder, (3) no reminder, and (4) interference control. For the groups, participants completed three visits (Visit 1, 2, and 3), which all occurred 48 hours apart. An exception to this was the interference control group, which did not complete Visit 2. On Visit 2, the reminder with exercise group engaged in a 15 min bout of high-intensity exercise (80% of heart rate reserve) immediately after memory reactivation. On Visit 3, participants engaged in a free recall (4 trials) of the memory task encoded on Visit 1. RESULTS: In a 4 (groups) × 4 (learning trials) mixed-measures ANOVA, with the group as the between-subjects variable and the learning trials (1-4) as the within-subject variable, there was a significant main effect group, F(3, 76) = 4.18, p = 0.008, η2p = 0.14, and a significant main effect for the learning trials, F(2.40, 182.59) = 49.25, p < 0.001, η2p = 0.39, but there was no group by learning trials interaction, F(7.20, 182.59) = 1.07, p = 0.38, η2p = 0.04. CONCLUSION: Our findings suggest that exercise may, potentially, attenuate memory distortion from memory reactivation. However, future work is needed to confirm these findings before any strong conclusions can be reached.

The effects of acute exercise intensity on episodic and false memory among young adult college students.

Background: Previous experimental work demonstrates that acute exercise may enhance episodic memory performance. However, limited research has examined the extent to which acute exercise influences false episodic memory production, and no studies, to date, have examined whether there is an intensity-specific effect of acute exercise on both true episodic and false episodic memories. Thus, the present experiment evaluated the effects of intensity-specific acute exercise on episodic memory and false episodic memory. Methods: A three-arm, parallel, between-group randomized controlled trial was employed in the University setting, with participants (N=60; Mage= 20.8 years) randomized into a moderate intensity exercise group (15-minute bout of treadmill exercise at 50% heart rate reserve), a high intensity exercise group (15-minute bout of treadmill exercise at 80% heart rate reserve), or a control group (time-matched period of sitting). True episodic and false episodic memory were both assessed using 6 word-lists from the Deese-Roediger-McDermott (DRM) paradigm, including both a short-term recall and a delayed memory recognition assessment. Results: For the number of words recalled across each of the 6 lists, there was a significant main effect for list (P<0.001, η2 p=0.15), marginally significant main effect for group (P=0.07, η2 p=0.09), but no list by group interaction effect (P=0.44, η2 p=0.03). Those in the high-intensity exercise group recalled significantly (P<0.05) more words than the control group. For the false episodic word recall, across various lists, high-intensity acute exercise was associated with a greater rate of false episodic memories. For the memory recognition task, there was no main effect for word type (P=0.46, η2 p=0.01), group (P=0.4443, η2 p=.03), word type by group interaction (P=0.44,η2 p=0.03), recall by group interaction (P=0.4441, η2 p=0.04), or word type by recall by group interaction (P=0.32, η2 p=0.04). However, there was a main effect for recall (P<0.001, η2 p=.54)and a word type by recall interaction (P<0.001, η2 p=0.77). Conclusion: These findings suggest that acute high-intensity exercise may enhance true episodic memories, and, possibly, also increase the rate of false episodic memories. We discuss these findings in the context of how different acute exercise intensities may have unique and differential effects on underlying mechanistic processes related to true and false episodic memory.