The memory‐impairing effects of simulated amnesia for a mock crime

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).

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.

The effect of lying on memory in daily life: Does motivation matter?

Recently, there has been renewed interest in the effect of lying on memory. A growing body of studies has documented that lying can impair memories and cause memory disruptions, such as forgetting and false memories, to a greater degree than telling the truth. This study aimed to investigate whether motivation plays a role in the effect of lying on memory. The present study utilized a daily life paradigm and manipulated three conditions: truth telling, internally motivated lying, and externally motivated lying. We asked participants to engage in a shopping task and to tell lies (externally motivated lying group) or to choose between telling the truth (truth-telling group) and telling lies (internally motivated lying group) in the interview. Forty-eight hours later, the participants were instructed to truthfully carry out multiple memory assessments. The principal findings of this research are that lying can result in memory impairments, and internally motivated lying can lead to greater impairment in source memory than externally motivated lying. Moreover, no significant differences between the two lying groups were found in the memory tests. The empirical findings of this study provide new insights into the effect of lying on memory.

Intrinsic motivation in a virtual reality mock crime affects participants' willingness to invest more effort in deceptive interviews

In studies of investigative interviewing, it is not well understood how participant experience of mock-crime activities might affect participants' desire to perform (well) in subsequent interviews. In this study, we utilized two immersive virtual reality mock-crimes to examine if participants' intrinsic motivation (i.e., competence, autonomy, relatedness) while committing the virtual mock-crime affects their desire to perform well in interviews. We also examined if the self-reported feeling of presence during the virtual reality mock-crime is associated with participants' intrinsic motivation. We found significant positive associations between presence and all intrinsic motivation variables in both truth and lie conditions. We also found that competence and relatedness significantly predicted the self-reported effort to perform well in interviews. We discuss these results in the context of prior literature and provide recommendations for researchers on the design of mock-crime experiences.

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.

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.

Research on the Effects of Lying on Memory: A Scientometric Analysis and a Call for New Studies

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 was conducted in order to visualize the state of the art on this line of research (i.e., authors, countries, institutions, journals, and co-citations). Additionally, a keywords’ cluster analysis was executed to investigate the main keywords used in the published papers. Based on the keywords’ cluster analysis, we identified the main aims and critical issues of the reviewed papers. The United States and the Netherlands are the two most productive countries into the effects of lying on memory. The top five authors are mainly from European countries and wrote from 6 to 15 articles. The cluster analysis detected three clusters of keywords. The critical issues of this line of research are mainly related to the generalizability of the achieved findings for real situations, a lack of a direct control of the manipulation adopted, and a need of additional measures. The current analysis provides a comprehensive overview and understanding of existing research on the effects of lying on memory and provides possible future directions of this research domain.

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.

The Memory-Undermining Effect of Simulated Crime-Related Amnesia and Its Legal Implications: a Review

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 the characteristics of the memory-undermining effect of simulated amnesia for a crime procedure (i.e., crime stimuli, simulating amnesia instructions, memory tests, and memory outcomes). We specifically focused on the effect that crime-related amnesia claims may have on offenders’ final memory reports. Our review showed that simulators who initially claimed amnesia might paradoxically experience some sort of forgetting pertaining to crime-related information. This issue could likely lead to legal complications that need be taken into account in crime-related amnesia cases.

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.

Do liars really remember what they lied upon? The impact of fabrication on memory

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 was instructed to tell the truth (i.e., truth-telling group), while the other two groups were instructed to lie either by partially distorting details (i.e., distortion group) or by completely making up wrong details of the event seen in the video (i.e., fabrication group). Two days later, participants completed a final memory test where they honestly answered recognition and recall questions concerning: (i) memory for the video and (ii) memory for having discussed details during the interview. Results showed that different types of fabrication affect liars' memory differently. Fabricators reported an undermining of memory for the event, whereas those who partially distorted details reported a higher impairment for the interview. Our findings showed that the effects of lying on liars' memory might be determined by the cognitive resources required to lie.

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.

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).

Do reminders of the crime reverse the memory-undermining effect of simulating amnesia?

Research shows that simulating amnesia impairs actual memory for a mock crime. Lack of rehearsal has been suggested as the most likely explanation for this finding because feigning amnesia is linked to reduced thinking about the offence. We investigated whether reminders about the crime could reverse the memory-undermining effect of simulation. In two studies, participants watched a video of a violent crime. After, they were asked to either simulate amnesia or confess the crime. During the week between the first and second memory test phase, participants were provided with reminders of the crime in two different modalities. In Study 1 (pilot), participants received frames of the mock crime video via WhatsApp. Findings showed that such reminders did not enhance ex-simulators' memory. In Study 2, participants were asked to put sequences of the mock crime in the right order. This latter modality led to enhanced memory for the offence in simulating participants. Theoretical and practical implications of our findings for the legal field are discussed.

Retrieval-Induced Forgetting in the Feigning Amnesia for a Crime Paradigm

Previous studies demonstrated that, when asked to honestly provide information about a mock crime, former feigners performed worse than those who were requested to confess to this event. Thus, feigning amnesia for a mock crime undermined genuine memory for the same experience. In the present study, we examined whether retrieval-induced forgetting (RIF) underlies this memory-undermining effect. After watching a mock crime, participants had to feign amnesia or confess to having committed that crime. Feigners were given retrieval practice instructions (i.e., retrieval-practice group) or no further instructions (i.e., control group). Immediately and 1 day later, all participants had to genuinely report what they remembered about the crime. Although simulators in the retrieval-practice group recalled the largest amount of information as a positive consequence of retrieval, the ratio for crucial crime-related details was lower than that exhibited by both simulators who were given no instructions and confessors. These findings suggest that RIF might play a role in forgetting critical information in claims of crime-related amnesia. Theoretical and practical implications will be discussed.