Decreased susceptibility to false memories from misinformation in hormonal contraception users

Sex hormones are increasingly implicated in memory formation. Recent literature has documented a relationship between hormones and emotional memory and sex differences, which are likely related to hormones, have long been demonstrated in a variety of mnemonic domains, including false memories. Hormonal contraception (HC), which alters sex hormones, has been associated with a bias towards gist memory and away from detailed memory in women who use it during an emotional memory task. Here, we investigated whether HC was associated with changes in susceptibility to false memories, which may be related to the formation of gist memories. We tested false memory susceptibility using two well-validated false memory paradigms: the Deese–Roediger–McDermott (DRM) task, and a story-based misinformation task. We found that hormonal contraceptive users were less susceptible to false memories compared to non-users in the misinformation task, and no differences were seen between groups on the DRM task. We hypothesise that the differences in false memories from the misinformation task may be related to hormonal contraceptive users' memory bias away from details, towards gist memory.     

The misinformation effect is unrelated to the DRM effect with and without a DRM warning

The misinformation and Deese–Roediger–McDermott (DRM) paradigms are used to study forms of false memories. Despite the abundance of research using these two paradigms, few studies have examined the relationship between the errors that arise from them. In the present study, 160 participants completed a misinformation task and two DRM tasks, receiving a warning about the effect before the second DRM task. Participants demonstrated misinformation and DRM effects (with and without the warning), but susceptibility to these forms of false memory were not significantly related across individuals. The DRM warning reduced the DRM effect, and signal detection analysis revealed that the DRM warning reduced a liberal response bias in this task. Sensitivity and response bias in both DRM tasks were not significantly related to these measures in the misinformation task. These findings suggest that these two forms of false memories are not interchangeable and they appear to be the result of different cognitive processes.     

Brief Exposure to Misinformation Can Lead to Long‐Term False Memories

Do false memories last? And do they last as long as true ones? This study investigated whether experimentally created false memories would persist for an extended period (one and a half years). A large number of subjects (N = 342) participated in a standard three‐stage misinformation procedure (saw the event slides, read the narrations with misinformation, and then took the memory tests). The initial tests showed that misinformation led to a significant amount of false memory. One and a half years later, the participants were tested again. About half of the misinformation false memory persisted, which was the same rate as for true memory. These results strongly suggest that brief exposure to misinformation can lead to long‐term false memory and that the strength of memory trace was similar for true and false memories. Copyright © 2011 John Wiley & Sons, Ltd.     

Do emotional stimuli enhance or impede recall relative to neutral stimuli? An investigation of two “false memory” tasks

Many eyewitness memory situations involve negative and distressing events; however, many studies investigating “false memory” phenomena use neutral stimuli only. The aim of the present study was to determine how both the Deese–Roediger–McDermott (DRM) procedure and the Misinformation Effect Paradigm tasks were related to each other using distressing and neutral stimuli. Participants completed the DRM (with negative and neutral word lists) and viewed a distressing or neutral film. Misinformation for the film was introduced and memory was assessed. Film accuracy and misinformation susceptibility were found to be greater for those who viewed the distressing film relative to the neutral film. Accuracy responses on both tasks were related, however, susceptibility to the DRM illusion and Misinformation Effect were not. The misinformation findings support the Paradoxical Negative Emotion (PNE) hypothesis that negative stimuli will lead to remembering more accurate details but also greater likelihood of memory distortion. However, the PNE hypothesis was not supported for the DRM results. The findings also suggest that the DRM and Misinformation tasks are not equivalent and may have differences in underlying mechanisms. Future research should focus on more ecologically valid methods of assessing false memory.     

Not lost in translation: writing auditorily presented words at study increases correct recognition “at no cost”

Previous studies have reported a translation effect in memory, whereby encoding tasks that involve translating between processing domains produce a memory advantage relative to tasks that involve a single domain. We investigated the effects of translation on true and false memories using the Deese/Roediger-McDermott (DRM) procedure [Deese, J. (1959). On the prediction of occurrence of particular verbal intrusions in immediate recall. Journal of Experimental Psychology, 58, 17–22; Roediger, H. L., III, & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, & Cognition, 21, 803–814]. Translation between modalities enhanced correct recognition but had no effect on false recognition. Results are consistent with previous research showing that correct memory can be enhanced “at no cost” in terms of accuracy. Findings are discussed in terms of understanding the relationship between true and false memories produced by the DRM procedure.     

Comparison of neural activity that leads to true memories,false memories,and forgetting: An fMRI study of the misinformation effect

False memories can occur when people are exposed to misinformation about a past event. Of interest here are the neural mechanisms of this type of memory failure. In the present study, participants viewed photographic vignettes of common activities during an original event phase (OEP), while we monitored their brain activity using fMRI. Later, in a misinformation phase, participants viewed sentences describing the studied photographs, some of which contained information conflicting with that depicted in the photographs. One day later, participants returned for a surprise item memory recognition test for the content of the photographs. Results showed reliable creation of false memories, in that participants reported information that had been presented in the verbal misinformation but not in the photographs. Several regions were more active during the OEP for later accurate memory than for forgetting, but they were also more active for later false memories, indicating that false memories in this paradigm are not simply caused by failure to encode the original event. There was greater activation in the ventral visual stream for subsequent true memories than for subsequent false memories, however, suggesting that differences in encoding may contribute to later susceptibility to misinformation.     

Can false memories prime problem solutions?

Previous research has suggested that false memories can prime performance on related implicit and explicit memory tasks. The present research examined whether false memories can also be used to prime higher order cognitive processes, namely, insight-based problem solving. Participants were asked to solve a number of compound remote associate task (CRAT) problems, half of which had been primed by the presentation of Deese/Roediger–McDermott (DRM) lists whose critical lure was also the solution to the problem. The results showed that when the critical lure: (a) was falsely recalled, CRAT problems were solved more often and significantly faster than problems that were not primed by a DRM list and (b) was not falsely recalled, CRAT problem solution rates and times were no different than when there was no DRM priming. A second experiment demonstrated that these outcomes were not a simple artifact of the inclusion of a recall test prior to the problem solving task. The implications of these results are discussed with regard to the previous literature on priming and the adaptive function of false memories.     

Is saccade-induced retrieval enhancement a potential means of improving eyewitness evidence?

Saccade-induced retrieval enhancement (SIRE) is the effect whereby making bilateral saccades enhances the subsequent retrieval of memories. Two experiments explored SIRE's potential to improve eyewitness evidence. Participants viewed slideshows depicting crimes, and received contradictory and additive misinformation about event details either once (Experiment 1) or three times (Experiment 2). Participants then performed saccades or a fixation control task before being tested on their memory for the slideshows and making confidence judgements. Saccades increased discrimination between seen and unseen event details regardless of whether or what type of misinformation was presented. Because prior studies indicated that SIRE might be more robust for individuals who are strongly right-handed versus not, we examined SIRE as a function of handedness and found that saccades improved memory for event details regardless of participants' handedness. However, participants who were not strongly right-handed had fewer false memories than participants who were strongly right-handed, extending previous findings of superior memory among individuals who are not strongly right-handed. Saccades also increased confidence in true memories (Experiment 1) and decreased confidence in false memories (Experiment 2). The results support SIRE's potential to improve eyewitness evidence.     

Cortisol response and psychological distress predict susceptibility to false memories for a trauma film

For eyewitness testimony to be considered reliable, it is important to ensure memory remains accurate following the event. As many testimonies involve traumatic, as opposed to neutral, events, it is important to consider the role of distress in susceptibility to false memories. The aim of this study was to investigate whether cortisol response following a stressor would be associated with susceptibility to false memories. Psychological distress responses were also investigated, specifically, dissociation, intrusions, and avoidance. Participants were allocated to one of three conditions: those who viewed a neutral film (N?=?35), those who viewed a real trauma film (N?=?35), and a trauma “reappraisal” group where participants were told the film was not real (N?=?35). All received misinformation about the film in the form of a narrative. Participants provided saliva samples (to assess cortisol) and completed distress and memory questionnaires. Cortisol response was a significant predictor of the misinformation effect. Dissociation and avoidance were related to confabulations. In conclusion, following a stressor an individual may differ with regard to their psychological response to the event, and also whether they experience a cortisol increase. This may affect whether they are more distressed later on, and also whether they remember the event accurately.     

Who is susceptible in three false memory tasks?

ABSTRACT

Decades of research show that people are susceptible to developing false memories. But if they do so in one task, are they likely to do so in a different one? The answer: “No”. In the current research, a large number of participants took part in three well-established false memory paradigms (a misinformation task, the Deese-Roediger-McDermott [DRM] list learning paradigm, and an imagination inflation exercise) as well as completed several individual difference measures. Results indicate that many correlations between false memory variables in all three inter-paradigm comparisons are null, though some small, positive, significant correlations emerged. Moreover, very few individual difference variables significantly correlated with false memories, and any significant correlations were rather small. It seems likely, therefore, that there is no false memory “trait”. In other words, no one type of person seems especially prone, or especially resilient, to the ubiquity of memory distortion.     

Treat and trick: A new way to increase false memory

This paper reports a new experimental manipulation that increased false memories 1 month after the manipulation. Mirroring the standard three‐stage misinformation paradigm (original event, misinformation, and test), subjects in the experimental group were first given a colour‐slide presentation of two stories (events), then given an accurate account (instead of misinformation) of the events in narrations, and finally tested for their memory of the original events. One month later, they underwent the standard misinformation paradigm with two new events. The comparison group was given the standard misinformation tasks at both time points. Results showed that the experimental group produced more false memories in the subsequent misinformation paradigm than did the comparison group. We focus on trust and credibility as possible mechanisms underlying this effect. Copyright © 2009 John Wiley & Sons, Ltd.     

Neural activity during encoding predicts false memories created by misinformation

False memories are often demonstrated using the misinformation paradigm, in which a person's recollection of a witnessed event is altered after exposure to misinformation about the event. The neural basis of this phenomenon, however, remains unknown. We used fMRI to investigate encoding processes during the viewing of an event and misinformation to see whether neural activity during either encoding phase could predict what would be remembered. fMRI data were collected as participants studied eight vignettes (Original Event phase). Shortly afterward, participants studied the same vignettes during scanning, but with changes to several details, serving as the misinformation (Misinformation phase). Two days later, their memories for the Original Event were assessed. Activity that subsequently led to true and false memories was examined during both encoding phases. Two interaction patterns between encoding phase (Original Event and Misinformation) and type of memory (true and false) were observed in MTL and PFC regions. In the left hippocampus tail and perirhinal cortex, a predictive item-encoding pattern was observed. During the Original Event phase, activity was greater for true than false memories, whereas during the Misinformation phase, activity was greater for false than true memories. In other regions, a pattern suggestive of source encoding was observed, in which activity for false memories was greater during the Original Event phase than the Misinformation phase. Together, these results suggest that encoding processes play a critical role in determining true and false memory outcome in misinformation paradigms.     

Reinstatement of odour context cues veridical memories but not false memories

ABSTRACT

The sense of smell has made a recent return to the forefront of research on episodic memory. Odour context cues can reactivate recently encoded memories during sleep-dependent memory consolidation [e.g., Rasch, B., Buchel, C., Gais, S., & Born, J. (2007). Odor cues during slow-wave sleep prompt declarative memory consolidation. Science, 315, 1426–1429], and reinstating the odour experienced during encoding at test results in superior recall and recognition [e.g., Isarida, T., Sakai, T., Kubota, T., Koga, M., Katayama, Y., & Isarida, T. K. (2014). Odor-context effects in free recall after a short retention interval: A new methodology for controlling adaptation. Memory & Cognition, 42, 421–433]. However, whether the impact of odour cues is restricted to the specific memories studied in the presence of the odour, or whether reinstating the odour also cues unstudied memories that are semantically related to the studied memories (i.e., false memories) is unknown. We used the Deese-Roediger-McDermott false memory paradigm to quantify the impact of odour cues on both veridical memory and false memory. Reinstating the odour presented during the study of the DRM word lists at the test phase resulted in better free recall of the studied words, but had no statistically significant impact on the number of false memories produced. We argue that odour cues influence recall of the memories they co-occurred with during study but potentially not semantically related memories.     

Working memory differences in illusory recollection of critical lures

In the present experiments, we explored the relationship between individual differences in working memory (WM) capacity and susceptibility to false recognitions and their accompanying subjective experiences. Deese/Roediger–McDermott (DRM) associative lists were used to elicit false memories, and remember/know judgments were used to measure the recollective experiences accompanying recognition decisions. We found that WM capacity was related to false recognitions of nonpresented critical lures and to the proportion of remember responses given to critical lures, such that higher WM capacity was associated with lower false-recognition rates and with lower proportions of remember responses. Importantly, these WM differences were only found when participants were forewarned about the nature of the DRM task prior to encoding (Exp. 1). When the forewarning was absent, WM capacity was not related to false recognitions or to the proportion of remember responses given to critical lures (Exp. 2). These results support the controlled-attention view of WM and suggest that subjective experiences of falsely recognized lures fluctuate as a function of WM capacity.     

The role of associative strength in children's false memory illusions

The effects of associative strength on rates of 7- and 11-year-old children's true and false memories were examined when category and Deese-Roediger-McDermott (DRM) lists were used to cue the same critical lure. Backward associative strength (BAS) was varied such that the category and DRM lists had the same strength (DRM=category), DRM lists had more BAS (DRM>category), or category lists had more BAS (DRM<category). If BAS drives children's false memories then BAS, not the type of relation across items in a list, should determine false memory production. The results confirmed this prediction using both recall and recognition measures: (1) both true and false memories increased with age, (2) true memory was better for category than DRM lists but there were no differences for false memory, and (3) at all ages, false memories varied predictably with changes in BAS but were unaffected by list-type manipulations. These findings are discussed in the context of models of false memory development.     

Age differences in the rejection of false memories: The effects of giving warning instructions and slowing the presentation rate

Two experiments were conducted to examine whether children of different ages differ in their ability to reject associative false memories with the Deese–Roediger–McDermott (DRM) paradigm. Two different types of manipulations that are thought to facilitate false memory rejection in adults—slowing the presentation rate and issuing explicit warnings—were analyzed in younger and older children. The results showed that older children were more able than younger children to reject associative false memories through warnings and by slowing the presentation rate. We conclude that although older children are, in general, more prone to produce false memories with the DRM paradigm, they are also more able to reject them when certain conditions facilitate the editing process.     

Poor working memory predicts false memories

Two studies investigated whether individual differences in simple span verbal working memory and complex working memory capacity are related to memory accuracy and susceptibility to false memory development. In Study 1, undergraduate students (N=60) were given two simple span working memory tests: forward and backward digit span. They also underwent a memory task that is known to elicit false memories of nonpresented words, the Deese/Roediger-McDermott (DRM) paradigm. Poor simple span working memory (as reflected by suboptimal backward digit span scores) was related to elevated levels of false recognition. Study 2 (N=65) replicated this finding, in that suboptimal backward digit span performance was found to be predictive of false recognition. However, complex working memory capacity (operation span) was not related to false recognition. This pattern suggests that even in a homogenous sample of undergraduates, poor working memory is associated with the susceptibility to recollect words never presented.     

Underestimation of prior remembering and susceptibility to false memories: two sides of the same coin?

In two studies, we explored whether susceptibility to false memories and the underestimation of prior memories (i.e., forgot-it-all-along effect) tap overlapping memory phenomena. Study 1 investigated this issue by administering the Deese/Roediger–McDermott task (DRM) and the forgot-it-all-along (FIA) task to an undergraduate sample (N = 110). It was furthermore explored how performances on these tasks correlate with clinically relevant traits such as fantasy proneness, dissociative experiences, and cognitive efficiency. Results show that FIA and DRM performances are relatively independent from each other, suggesting that these measures empirically apparently refer to separate dimensions. However, they do not seem to define different profiles in terms of dissociation, fantasy proneness, and cognitive efficiency. Study 2 replicated the finding of relative independence between false memory propensity (as measured with the DRM task) and the underestimation of prior memories (as measured with an autobiographical memory dating task) in people with a history of childhood sexual abuse (N = 35).     

False memory in a short-term memory task

The Deese/Roediger-McDermott (DRM; Roediger & McDermott, 1995) paradigm reliably elicits false memories for critical nonpresented words in recognition tasks. The present studies used a Sternberg (1966) task with DRM lists to determine whether false memories occur in short-term memory tasks and to assess the contribution of latency data in the measurement of false memories. Subjects studied three, five, or seven items from DRM lists and responded to a single probe (studied or nonstudied). In both experiments, critical lures were falsely recognized more often than nonpresented weak associates. Latency data indicated that correct rejections of critical lures were slower than correct rejections of weakly related items at all set sizes. False alarms to critical lures were slower than hits to list items. Latency data can distinguish veridical and false memories in a short-term memory task. Results are discussed in terms of activation-monitoring models of false memory.     

Mood-congruent false memories in the DRM paradigm

This study investigated the creation of mood-congruent false memories within the Deese–Roediger–McDermott (DRM) paradigm using recall and recognition of critical lures as performance measures. Participants (n=93) were randomly assigned to three mood-induction conditions (positive, negative and control) and were presented with positive, negative and neutral DRM word lists in audio form. We predicted that intrusion errors of the critical lures would be higher in the mood-congruent conditions. Results confirmed this prediction and extended previous DRM research by showing that already high false memory rates were increased when the valence of the lures matched the mood-induction condition. Furthermore, participants made more “remember” judgements for the emotion critical lures in their mood-congruent conditions. Discussion draws on spreading activation explanations of DRM findings, and considers how moods could increase activation of non-presented information.