The development of differential mnemonic effects of false denials and forced confabulations

The effects of deception on memory: a comparative study of actors and eyewitnesses accounts

Deception is a common occurrence in daily life and has been shown to impair memory. This study investigated the memory-undermining effects of deception in a simulated daily life scenario, focusing on the potential moderating effect of the liars' role (i.e., actor vs. eyewitness). In a 2 × 2 between-subjects design, 128 participants were randomly assigned to one of four conditions: actors who told the truth, actors who lied, eyewitnesses who told the truth, and eyewitnesses who lied. Participants engaged in a simulated shopping task, followed by an interview where they either provided truthful or deceptive responses about the items they bought (actors) or observed (eyewitnesses). Two days later, participants completed a series of memory tests assessing item memory, source memory, destination memory, and non-believed memories. Results showed that deception impaired source memory, with a greater impairment observed for actors than eyewitnesses. Deception also led to more non-believed memories and impaired item and destination memory, regardless of the liars' role. These findings suggest that the role of liars moderates the effects of deception on memory, with self-related deception (actors) leading to greater memory impairments than other-related deception (eyewitnesses).

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.

Methods and measures of source monitoring in children: A scoping review

Source monitoring (SM) refers to attributing sources of information. There are various methods for measuring SM in children. We searched the PubMed, PsycINFO, Embase, Web of Science and Cochrane Library databases from their inception to February 24, 2023, to summarize the methods and measures of SM in children, identifying 141 studies. The procedure for the SM tasks encompassed encoding, interval and testing. The encoding tasks were classified into ground-based activities (n = 67), computer-based experiments (n = 42) and mixed methods (n = 34). The testing approaches were categorized into old/new recognition and source discrimination, n-alternative forced-choice, yes/no questions and recall/direct questions. Among 10 commonly used indicators, source-correct, source-incorrect, discrimination score and source accuracy were recommended to present the SM function. We also discussed the advantages and disadvantages of different SM methods in children, providing a reference for researchers to design and select SM measurements that meet their research objectives.

Mixed in a World of Truth and Lies: List Composition Moderates the Effects of a Lie Fabrication Manipulation on Memory and Metamemory

Research has shown that list composition moderates the effects of encoding manipulations on memory performance; differential memory performance is observed at distinct levels of the independent variable in mixed lists, but not in pure lists. The current study aims to investigate the effect of list composition on predicted and actual memory performance using a semantic lie fabrication manipulation. In Experiment 1, participants either told the truth or fabricated a lie in response to a set of general knowledge questions in a mixed-list design, made memory predictions for each response, and received a free recall test. Experiments 2A and 2B compared the effect of list composition by employing mixed and pure lists, respectively. The results showed that the lie fabrication led to a metacognitive illusion in mixed lists by inducing a crossed double dissociation between memory and metamemory. Participants produced higher memory performance and lower memory predictions for lies than the truth. In contrast, predicted and actual memory performance were similar for truth and lies in pure lists. These findings contribute to the existing body of knowledge on list composition and have implications for situations where individuals need to maintain and remember their fabricated lies.

Witnesses' susceptibility to misleading post-event information delivered in a social media-style video

In many criminal cases, outcomes rely on eyewitness evidence. Exposure to misleading information after an event reduces the accuracy of witnesses' memories. In some circumstances, warnings about misinformation can protect witnesses. As social media is a growing source of misleading information, this study examined the effect of misleading post-event information delivered via a social media-style video, as well as the utility of a minimal versus detailed warning. Participants (N = 145) watched a video showing an electrician stealing items from a client's home. Next, they received one of three pre-warnings regarding forthcoming misleading information: a minimal warning indicating that caution should be taken, a detailed warning specifying the presence of misleading information, or no warning. Participants received the misleading information via a social media video or a standard text-based narrative. Finally, they completed a recognition test. Although delivery method did not affect errors for misleading items, detailed warnings were only effective against text-based misleading information. Participants were more confident about their correct than incorrect responses for misleading items; confidence was not affected by delivery method or warning. This experiment is the first to demonstrate people's susceptibility to misleading post-event information delivered in a social media-style video using an eyewitness paradigm.

Inducing emotionally negative nonbelieved memories using negative pictures

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 negative pictures, participants had to rate their emotional state. One week later, in Session 2, participants had to complete a recognition task to identify pictures that had appeared during the previous session. During this task, participants' memories for some pictures were challenged by telling them that their answers were incorrect in order to evoke nonbelieved memories. The experimental procedure was successful in creating nonbelieved memories in the participants. Specifically, in Experiment 1 (N = 35), we induced nonbelieved true memories for both negative and neutral pictures. We found a significant decrease in both belief and recollection after the challenge, with the change in belief being twice as large as the change in recollection. In Experiment 2 (N = 43), we successfully induced both nonbelieved true and false memories for negative pictures. Again, the reduction of belief was significantly greater than that of recollection. In general, participants evinced better memory for negative pictures, but following challenges people were just as likely to accept false social feedback and change their memories regarding other types of pictures. In both experiments, our challenges did not lead to notable changes in emotional state. In general, our findings show that emotionally negative nonbelieved memories can be successfully evoked in an experimental setting.

External and internal influences yield similar memory effects: the role of deception and suggestion

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 (e.g., suggestive interviews) can hurt memory. 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 available evidence suggests that both external and internal influences exert similar effects on memory. That is, we review studies showing that suggesting non-occurrences and suggesting non-experiences can lead to omission errors and false memories, respectively. Likewise, these memory effects are also observed when focusing on internal influences. That is, false denials, feigning amnesia and fabrication have been shown to affect memory in terms of forgetting (i.e., omissions) and false memories (i.e., commissions). Also, we show that both external and internal influences can lead to changes in the belief that an event occurred. We argue that in legal cases, triers of fact should concentrate on whether both types of influences might have affected testimonial accuracy in witnesses, victims, and suspects.

Can false denials turn fact into fiction? The effect of false denials on memory for self-performed actions

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 tested. Subsequently, participants were instructed to repeatedly deny an action they had performed (false denial) and to repeatedly claim to have performed an action they had only imagined (false admission). In a final sorting memory task, 54% (n = 16) of participants erroneously indicated, after false admissions, that they had performed the imagined action. None of the participants indicated that they had only imagined an action after false denials, showing that it might be difficult to forget a performed action, even after repeatedly denying it. The current experiment sets the stage for future research to investigate why it seems to be difficult to forget performed actions.

Factors affecting the forced confabulation effect: a meta-analysis of laboratory studies

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 events (i.e., forced confabulation effect). Results showed that forced confabulation indeed led to the production of false memories. Qualitative reviews of studies suggested that the forced confabulation effect is enhanced after receiving confirmatory feedback. Moreover, we found evidence that longer delays between the forced confabulation phase and the final memory task are necessary to observe the forced confabulation effect for entire events. However, caution is needed when interpreting the forced confabulation effect. Specifically, our moderator analyses revealed that voluntarily produced confabulation led to more false memories than forced confabulation. Also, our exploratory analysis indicated that the forced confabulation effect was mainly observed in within-subject designs. Taken together, our meta-analysis supports the notion that forcing participants to confabulate can lead them to later report such confabulations as part of the truth. Nonetheless, caution is warranted because this effect might be due to the introduction of misinformation through asking unanswerable questions.

Online dating through lies: the effects of lie fabrication for personal semantic information on predicted and actual memory performance

Research shows that people lie on online dating sites often but might fail to remember this information subsequently. This study investigated participants' predicted and actual memory performance for personal semantic information after telling the truth versus a lie in two experiments in a setup similar to online dating sites. In Experiment 1, participants responded to open-ended questions either truthfully or fabricated lies in a within-subjects design, followed by predictions for remembering their responses. Subsequently, they recalled their responses through free-recall. Using the same design, Experiment 2 also manipulated the type of retrieval task by using a free- or cued-recall test. The results showed that participants consistently had higher memory predictions for truthful than deceptive responses. However, the actual memory performance did not always produce similar results to their predictions. The results suggest that the difficulties during lie fabrication, measured through response latencies, partially mediated the relationship between lying and memory predictions. The study has important applied implications for lying about personal semantic information in online dating contexts.

False denials increase false memories for trauma-related discussions

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 and twenty-six participants watched a trauma analogue video of a car crash before being randomly asked in a discussion with the experimenter to (1) respond honestly or (2) falsely deny that certain details happened in the video. After one week, all participants received misinformation about the discussion with the experimenter and the car crash. Finally, all participants were instructed to respond truthfully in a source memory task. Participants who falsely denied information during the first session were statistically significantly more prone than honest participants to omit details they denied and to report misinformation about what was discussed in the first session. Our work suggests that false denials of a traumatic experience might lead to both forgetting and increased false memory levels for earlier conversations about the event.

Simulating denial increases false memory rates for abuse unrelated information

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. One week later, participants received misinformation for the narrative and interview. In a final source memory task, participants' memory for the narrative and interview was tested. Participants who falsely denied abuse-related information endorsed more abuse-unrelated misinformation about the event than honest participants. Abuse-related false memory rates did not statistically differ between the groups, and false denials were not related to omission errors about (1) the interview and (2) narrative. Hence, victim's memory for abuse-related information related to their experience might not be affected by a false denial, and inconsistencies surrounding the abuse-unrelated information are more likely to take place.

More Lies Lead to More Memory Impairments in Daily Life

Previous studies have demonstrated that lying can undermine memory and that its memory-undermining effects could be modulated by the cognitive resources required to tell lies. We extended the investigation of the memory-undermining effect by using a daily life setting in which participants were highly involved in a mock shopping task. Participants were randomly assigned to truth-telling, denying or mixed lying conditions. After finishing the shopping task, participants were told that two people wanted to know about their shopping lists and would ask them some questions in an interview. During the interview, participants were asked whether each of ten items were on the shopping list, five of which were randomly selected from the shopping list, while the other five were not sold in the store. In answering the interview questions, the truth-telling group was asked to respond honestly, the denying group was asked to give denial responses, and the mixed lying group was asked to respond deceptively. Thus, the denying group told five lies and the mixed lying group told ten lies in the interview. The item memory test, source memory test and destination memory test were given in an orderly manner 48 h after the interview. We found that the mixed lying group, rather than the denying group, forgot the lies they told in the interview and mistakenly believed they had lied about something that they had not lied about. Moreover, the mixed lying group retained fewer memories about the person they responded to than the honest group. In addition, participants in the mixed lying group had more non-believed memories than those in the truth-telling group in both item and source memory tests. We conclude that more lies could result in more memory disruptions in daily life.

Who did I lie to that day? Deception impairs memory in daily life

Research has demonstrated that deceptive responses can undermine item and source memories. However, previous studies have often randomly assigned participants to an honest or deception group and asked them to respond in specific ways in an interview, rather than providing them a choice of what response to give. Moreover, little attention has been given to destination memory in previous research. Using a daily life paradigm, we investigated the effects of deception on memory. After completing a mock shopping task, participants were told that someone would ask them questions about their shopping lists. The participants voluntarily chose to tell the truth or lie in the interview and were encouraged to respond as they would in their daily lives. An item memory test, source memory test and destination memory test were given 48 h after the interview. Source and destination memories but not item memories were impaired for participants who chose to lie. Specifically, liars forgot the things about which they lied and mistakenly believed that they lied about many things that they did not, and they also did not remember to whom they lied. We conclude that deception can disrupt memory in daily life.

Does experiencing inattentional blindness for crime influence eyewitness recall?

Witnesses may not notice crimes occurring when their attention is elsewhere, which may affect their memory. In this study, 174 participants completed an attention-demanding task while viewing a video containing an assault. Whether participants noticed the assault or experienced inattentional blindness for it was assessed. Then, participants were exposed to post-event information (containing misinformation) before completing a cued-recall task under one of three recall instructions (free, forced, or no instruction). Most participants experienced inattentional blindness for the assault (65.5%), which had a negative effect on recall, regardless of recall instruction. Specifically, participants who experienced inattentional blindness were less confident, complete, and accurate, and were more likely to report misinformation, than participants who noticed the crime. Witnesses who experienced inattentional blindness reported that they relied purely on post-event information to answer some questions. The findings suggest that caution should be taken when interviewing witnesses who have not paid attention to a crime.

Involvement Modulates the Effects of Deception on Memory in Daily Life

Previous studies have demonstrated that liars who adopt a false denial strategy often forget what they lied about, which has been labeled the denial-induced forgetting (DIF) effect. However, several investigations have not found such an effect. It has been suggested that involvement might play a role in the inconsistency. The present study was designed to directly determine whether involvement modulates the effects of deception on memory. Participants were assigned randomly to either high- or low-involvement conditions and were required to complete a mock shopping task. They were then asked to participate in an interview in which they were asked to respond honestly or deceptively. Two days later, final memory tests were given, and the participants were asked to give honest responses. We found a DIF effect in the high-involvement condition but not in the low-involvement condition. Moreover, the liars in the high-involvement condition created more non-believed memories in the source memory test and the destination memory test than the honest participants. In addition, liars in both the high- and low-involvement conditions forgot who they lied to. We conclude that the effects of deception on memory could be influenced by the degree of involvement.

The role of executive functions in the effects of lying on memory

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 (i.e., EF: Shifting, Inhibition, and Updating). A sample of 147 participants watched a video of a robbery and then were instructed to either fabricate (i.e., fabrication condition), deny (i.e. false denial condition), or tell the truth (i.e., truth-telling condition) to some questions about the crime. Two days later, all participants had to provide an honest account on a final memory test where they indicated their memory for having discussed details (i.e., fabricated, denied, or told the truth) and their memory for the video. Finally, their EF resources were also assessed. Our findings demonstrated that individual differences in EFs played a role in how the event was recalled and on the effects of lying on memory. That is, memory for the event after having lied depended especially on individuals' Shifting resources. We also found that the two deceptive strategies differentially affected individuals' memory for the interview and for the event: Denying affected memory for the interview while fabricating affected memory for the event. Our findings can inform legal professionals on the possibility to assess individuals' EF as an indicator of witnesses' credibility.

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.

Can suggestions of non-occurrence lead to claims that witnessed events did not happen?

In three experiments, we examined whether general suggestions of non-occurrence -suggestions that experienced events did not occur- would lead participants to claim that events they witnessed never happened. Participants viewed a video depicting the investigation of a child kidnapping case and subsequently were exposed to suggestions of non-occurrence either once (Experiments 1 and 3) or three times (Experiments 2 and 3). The results provided no evidence that single suggestions of non-occurrence influenced participants' memories or belief (Experiments 1 and 3). However, in two experiments (E2 and E3) the results provided clear evidence that repeated elaboration of suggestions of non-occurrence led participants to claim that the events they witnessed never happened. The finding that participants were influenced by repeated, but not single elaboration of suggestions of non-occurrence shows that reflective elaboration processes played an important role in leading participants to disbelieve the events they had witnessed.

The impact of false denials on forgetting and false memory

People sometimes falsely deny having experienced an event. In the current experiments, we examined the effect of false denials on forgetting and false memory formation. In Experiment 1, participants were presented with emotionally-negative and neutral associatively related word lists known to engender false memories. After encoding, half of the participants had to falsely deny having seen the words while the other half had to tell the truth. During a final memory test (recall or source monitoring task), participants who falsely denied forgot that they discussed certain words with an experimenter. Furthermore, the act of falsely denying reduced the formation of false memories. These results were partially replicated in Experiment 2 where participants also had to re-learn several words and received a second memory task. This latter design feature diminished the effect of false denials on false memory creation. Our experiments suggest that false denials not only have negative consequences (forgetting), but can have positive ones too (reduction in false memories).

The impact of lying about a traumatic virtual reality experience on memory

The goal of the present experiment was to examine the effect of certain (deceptive) strategies (e.g., false denial) on memory. Specifically, participants were shown a traumatic virtual reality (VR) video of an airplane crash. Following this, participants (N= 94) received questions concerning details from the VR scene in a baseline memory task. Then, participants could choose from 3 options how to cope in response to having experienced the VR scene: tell the truth, falsely deny, or fabricate. The majority opted to tell the truth (n = 81). A subsample of truth tellers were instructed to falsely deny having seen certain details. One week later, all participants received a source monitoring task in which they were asked (1) whether they remembered talking about these details during an interview, and (2) whether they remembered seeing certain details during the VR experience the week before. Participants had to tell the truth during this task. Participants who were instructed to falsely deny showed impaired memory for presented details that had previously been discussed (i.e., denial-induced forgetting) and seen in the VR scene. Also, the presentation of certain details in the baseline memory task seemed to inoculate participants who were instructed to falsely deny from experiencing memory impairment. The current experiment suggests that false denials can have adverse ramifications for memory for what is discussed and seen.

Forgetting having denied: The "amnesic" consequences of denial

The concept of denial has its roots in psychoanalysis. Denial has been assumed to be effective in blocking unwanted memories. In two experiments, we report that denial has unique consequences for remembering. In our two experiments, participants viewed a video of a theft, and half of the participants had to deny seeing certain details in the video, whereas the other half had to tell the truth. One day later, all participants were given either a source-monitoring recognition or a recall task. In these tasks, they were instructed to indicate (1) whether they could remember talking about certain details and (2) whether they could recollect seeing those details in the video. In both experiments, we found that denial made participants forget that they had talked about these details, while leaving memory for the video itself unaffected. This denial-induced forgetting was evident for both the source-monitoring recognition and recall tests. Furthermore, when we asked participants after the experiment whether they could still not remember talking about these details, those who had to deny were most likely to report that they had forgotten talking about the details. In contrast to a widely held belief, we show that denial does not impair memory for the experienced stimuli, but that it has a unique ability to undermine memory for what has been talked about.