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.     

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.     

Correcting false information in memory: Manipulating the strength of misinformation encoding and its retraction

Information that is presumed to be true at encoding but later on turns out to be false (i.e., misinformation) often continues to influence memory and reasoning. In the present study, we investigated how the strength of encoding and the strength of a later retraction of the misinformation affect this continued influence effect. Participants read an event report containing misinformation and a subsequent correction. Encoding strength of the misinformation and correction were orthogonally manipulated either via repetition (Experiment 1) or by imposing a cognitive load during reading (Experiment 2). Results suggest that stronger retractions are effective in reducing the continued influence effects associated with strong misinformation encoding, but that even strong retractions fail to eliminate continued influence effects associated with relatively weak encoding. We present a simple computational model based on random sampling that captures this effect pattern, and conclude that the continued influence effect seems to defy most attempts to eliminate it.     

Witnessing postevents does not change memory traces,but can affect their retrieval

The results of three experiments suggest that a memory trace for an event is not altered by witnessing similar events, but that postevents can interfere with its retrieval. On an immediate recall test, details from an original story (e.g. wrench) were recalled less often if a subsequent story mentioned a ‘screwdriver’ than if it did not. The interference effect occurred if people were asked to recall details fromboth stories (tool —— ——), but not if people were asked to recall primarily from the first story. Thus, the interference effect in immediate recall was averted if the target trace could be activated selectively (Experiments 1a and 1b). A more general interference effect was found after a day. Fewer targets from the original story were recalled if the second story was presented just before the test than if both stories occurred a day earlier. Thus, the second story interfered with recall only if it emphasized contextual retrieval cues that did not match the trace for the targets (Experiment 2). Copyright © 2001 John Wiley & Sons, Ltd.     

Explicit warnings reduce but do not eliminate the continued influence of misinformation

Information that initially is presumed to be correct, but that is later retracted or corrected, often continues to influence memory and reasoning. This occurs even if the retraction itself is well remembered. The present study investigated whether the continued influence of misinformation can be reduced by explicitly warning people at the outset that they may be misled. A specific warning— giving detailed information about the continued influence effect (CIE)—succeeded in reducing the continued reliance on outdated information but did not eliminate it. A more general warning—reminding people that facts are not always properly checked before information is disseminated—was even less effective. In an additional experiment, a specific warning was combined with the provision of a plausible alternative explanation for the retracted information. This combined manipulation further reduced the CIE but still failed to eliminate it altogether.     

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.     

Children's Ideas About What Can Really Happen: The Impact of Age and Religious Background

Five- to 11-year-old U.S. children, from either a religious or secular background, judged whether story events could really happen. There were four different types of stories: magical stories violating ordinary causal regularities; religious stories also violating ordinary causal regularities but via a divine agent; unusual stories not violating ordinary causal regularities but with an improbable event; and realistic stories not violating ordinary causal regularities and with no improbable event. Overall, children were less likely to judge that religious and magical stories could really happen than unusual and realistic stories although religious children were more likely than secular children to judge that religious stories could really happen. Irrespective of background, children frequently invoked causal regularities in justifying their judgments. Thus, in justifying their conclusion that a story could really happen, children often invoked a causal regularity, whereas in justifying their conclusion that a story could not really happen, they often pointed to the violation of causal regularity. Overall, the findings show that children appraise the likelihood of story events actually happening in light of their beliefs about causal regularities. A religious upbringing does not impact the frequency with which children invoke causal regularities in judging what can happen, even if it does impact the type of causal factors that children endorse.     

Political Attitudes and the Processing of Misinformation Corrections

Misinformation often continues to influence people’s memory and inferential reasoning after it has been retracted; this is known as the continued influence effect (CIE). Previous research investigating the role of attitude‐based motivated reasoning in this context has found conflicting results: Some studies have found that worldview can have a strong impact on the magnitude of the CIE, such that retractions are less effective if the misinformation is congruent with a person’s relevant attitudes, in which case the retractions can even backfire. Other studies have failed to find evidence for an effect of attitudes on the processing of misinformation corrections. The present study used political misinformation—specifically fictional scenarios involving misconduct by politicians from left‐wing and right‐wing parties—and tested participants identifying with those political parties. Results showed that in this type of scenario, partisan attitudes have an impact on the processing of retractions, in particular (1) if the misinformation relates to a general assertion rather than just a specific singular event and (2) if the misinformation is congruent with a conservative partisanship.     

Prime time news: The influence of primed positive and negative emotion on susceptibility to false memories

We examined the relation between emotion and susceptibility to misinformation using a novel paradigm, the ambiguous stimuli affective priming (ASAP) paradigm. Participants (N = 88) viewed ambiguous neutral images primed either at encoding or retrieval to be interpreted as either highly positive or negative (or neutral/not primed). After viewing the images, they either were asked misleading or non-leading questions. Following a delay, memory accuracy for the original images was assessed. Results indicated that any emotional priming at encoding led to a higher susceptibility to misinformation relative to priming at recall. In particular, inducing a negative interpretation of the image at encoding led to an increased susceptibility of false memories for major misinformation (an entire object not actually present in the scene). In contrast, this pattern was reversed when priming was used at recall; a negative reinterpretation of the image decreased memory distortion relative to unprimed images. These findings suggest that, with precise experimental control, the experience of emotion at event encoding, in particular, is implicated in false memory susceptibility.     

Causal Attribution and Perceived Realism of Stories

Just as people generate causal explanations for social events around them, story readers usually generate inferences about causality of events when reading a story. The attribution literature suggests that, when judging events that happen to others, people spontaneously generate dispositional explanations for negative events and situational explanations for positive events and the reverse when judging events that happen to themselves. Three experiments examined how these spontaneously generated inferences of causality interacted with causal explanations provided by the text of a story to influence perceived realism. The results indicate that the relationship between spontaneously generated causal attributions and information supplied by the story had little influence on realism judgments about story characters or about other people. When evaluating the story scenario for the self, however, results of all three experiments show that people find information consistent with their own spontaneous attributions more realistic. The results contribute to our understanding of the psychological processes that may drive realism evaluations of stories and possible contrasting mechanisms between attributions in story worlds and the social world.     

Reactions to blatantly contradictory information

In two experiments, subjects were shown a complex event and were later exposed to misinformation about that event. In addition, some subjects received a piece of blatantly contradictory misinformation. Blatant misinformation both was rejected by subjects and caused them to be more resistant to other misinformation that they would ordinarily have been inclined to accept the “spillover” effect. However, delaying the blatant misinformation until the other pieces of false information had already been processed destroyed its ability to make subjects immune to such “ordinary” misinformation. These results are consistent with the idea that subjects incorporate new information into memory at the time it is initially introduced and use this information to update an existing memorial representation.     

Attentional responses on an auditory oddball predict false memory susceptibility

Attention and memory are highly integrated processes. Building on prior behavioral investigations, this study assesses the link between individual differences in low-level neural attentional responding and false memory susceptibility on the misinformation effect, a paradigm in which false event memories are induced via misleading post-event information. Twenty-four subjects completed the misinformation effect paradigm after which high-density (256-channel) EEG data was collected as they engaged in an auditory oddball task. Temporal-spatial decomposition was used to extract two attention-related components from the oddball data, the P3b and Classic Slow Wave. The P3b was utilized as an index of individual differences in salient target attentional responding while the slow wave was adopted as an index of variability in task-level sustained attention. Analyses of these components show a significant negative relationship between slow-wave responses to oddball non-targets and perceptual false memory endorsements, suggestive of a link between individual differences in levels of sustained attention and false memory susceptibility. These findings provide the first demonstrated link between individual differences in basic attentional responses and false memory. These results support prior behavioral work linking attention and false memory and highlight the integration between attentional processes and real-world episodic memory.     

Beliefs Don't Always Persevere: How Political Figures Are Punished When Positive Information about Them Is Discredited

Recent research has extended the belief‐perseverance paradigm to the political realm, showing that negative information about political figures has a persistent effect on political opinions even after it has been discredited. However, little is known about the effects of false positive information about political figures. In three experiments, we find that discrediting positive information generates a “punishment effect” that is inconsistent with the previous literature on belief perseverance. We argue people attempt to adjust for the perceived influence of the false claim when the information is discredited. In this case, when trying to account for the effects of discredited positive information about a politician, people overestimate how much correction is needed and thus end up with a more negative opinion. (By contrast, people underestimate how much correction is needed to adjust for false negative information, leading to belief perseverance.) These results suggest that bogus credit claiming or other positive misinformation can have severe repercussions for politicians.     

The relationship between DRM and misinformation false memories

This research investigated the relationship between false memories induced by two different paradigms (misinformation and Deese–Roediger–McDermott [DRM]). The misinformation effect refers to the phenomenon that a person’s recollection of a witnessed event can be altered after exposure to misleading information about the event. DRM false memory represents the intrusion of words that are semantically related but not actually presented in the study session. Subjects (N = 432) completed both misinformation and DRM false memory tests. Results showed a small but significant correlation (r = .12, p = .02) between the misinformation and DRM false memories. Furthermore, using signal detection theory, we found that the discrimination ability index (d′) was related to both the misinformation and DRM false memories (r = ?.12 and ?.13, p = .01), while the response bias was related only to DRM false memory (r = ?.46, p < .001). These results suggest that misinformation and DRM false memories generally involve different mechanisms and that their shared mechanism may involve the global discrimination ability.     

The information effect: constructive memory, testimony, and epistemic luck

The incorporation of post-event testimonial information into an agent’s memory representation of the event via constructive memory processes gives rise to the misinformation effect, in which the incorporation of inaccurate testimonial information results in the formation of a false memory belief. While psychological research has focussed primarily on the incorporation of inaccurate information, the incorporation of accurate information raises a particularly interesting epistemological question: do the resulting memory beliefs qualify as knowledge? It is intuitively plausible that they do not, for they appear to be only luckily true. I argue, however, that, despite its intuitive plausibility, this view is mistaken: once we adopt an adequate (modal) conception of epistemic luck and an adequate (adaptive) general approach to memory, it becomes clear that memory beliefs resulting from the incorporation of accurate testimonial information are not in general luckily true. I conclude by sketching some implications of this argument for the psychology of memory, suggesting that the misinformation effect would better be investigated in the context of a broader “information effect”.     

Self-relevance enhances susceptibility to false memory

Eyewitness testimony serves as important evidence in the legal system. Eyewitnesses of a crime can be either the victims themselves—for whom the experience is highly self-referential—or can be bystanders who witness and thus encode the crime in relation to others. There is a gap in past research investigating whether processing information in relation to oneself versus others would later impact people's suggestibility to misleading information. In two experiments (Ns = 68 and 122) with Dutch and Chinese samples, we assessed whether self-reference of a crime event (i.e., victim vs. bystander) affected their susceptibility to false memory creation. Using a misinformation procedure, we photoshopped half of the participants' photographs into a crime slideshow so that they saw themselves as victims of a nonviolent crime, while others watched the slideshow as mock bystander witnesses. In both experiments, participants displayed a self-enhanced suggestibility effect: Participants who viewed themselves as victims created more false memories after receiving misinformation than those who witnessed the same crime as bystanders. These findings suggest that self-reference might constitute a hitherto new risk factor in the formation of false memories when evaluating eyewitness memory reports.     

Promoting Honesty: The Influence of Stories on Children's Lie‐Telling Behaviours and Moral Understanding

Moral stories are a means of communicating the consequences of our actions and emphasizing virtuous behaviour, such as honesty. However, the effect of these stories on children's lie‐telling has yet to be thoroughly explored. The current study investigated the influence of moral stories on children's willingness to lie for another individual. Children were read one of three stories prior to being questioned about an accidental wrongdoing: (1) a positive story, which emphasized the benefits of being honest; (2) a negative story, which outlined the potential costs of lying; and (3) a neutral story, which was unrelated to truth‐telling or lie‐telling. Initially, most children withheld information about the event. Older children were better able to maintain their lies throughout the interview. However, when asked direct questions, children in the positive story condition were more likely to tell the truth than those in the negative and neutral conditions. No significant differences were found between the negative and neutral story conditions. The present study also investigated the relationship between children's conceptual understanding and behaviour. The findings revealed that children's knowledge of truths and lies increased with age. Children who lied had significantly higher conceptual scores than those who did not lie. Furthermore, the type of story children were read had a significant impact on their evaluations of true and false statements. Copyright © 2015 John Wiley & Sons, Ltd.     

Misled subjects may know more than their performance implies

Many studies have demonstrated that subjects exposed to misleading postevent information are likely to report the misinformation with confidence on subsequent tests of memory for the event. The purpose of the present studies was to determine whether subjects exposed to misleading postevent information come to believe they remember seeing the misinformation at the original event. A second question addressed by the present studies is whether exposure to misinformation reduces subjects' ability to remember the source of items they witnessed at the original event. In two experiments, subjects viewed a slide sequence depicting an event, were subsequently exposed to misleading information or neutral information about selected aspects of the event, and were later tested on their memory for the source of original and misleading details. The results showed that exposure to misinformation did not lead subjects to believe they remembered seeing the misinformation, nor did it reduce subjects' ability to accurately identify the source of originally seen details. The same pattern of results was obtained whether subjects were tested immediately (Experiment 1) or after a 1-day delay (Experiment 2). Collectively, the results suggest that subjects may report misinformation even if they know they do not remember seeing it.     

False memories in music listening: exploring the misinformation effect and individual difference factors in auditory memory

ABSTRACT

The study of false memory has had a profound impact on our understanding of how and what we remember, as shown by the misinformation paradigm [Loftus, E. F. (2005). Planting misinformation in the human mind: A 30-year investigation of the malleability of memory. Learning & Memory, 12(4), 361–366. doi:10.1101/lm.94705]. Though misinformation effects have been demonstrated extensively within visual tasks, they have not yet been explored in the realm of non-visual auditory stimuli. Thus, the present study aimed to investigate whether post-event information can create false memories of music listening episodes. In addition, we explored individual difference factors potentially associated with false memory susceptibility in music, including age, suggestibility, personality, and musical training. In two music recognition tasks, participants (N?=?151) listened to an initial music track, which unbeknownst to them was missing an instrument. They were then presented with post-event information which either suggested the presence of the missing instrument or did not. The presence of misinformation resulted in significantly poorer performance on the music recognition tasks (d?=?.43), suggesting the existence of false musical memories. A random forest analysis indicated that none of the individual difference factors assessed were significantly associated with misinformation susceptibility. These findings support previous research on the fallibility of human memory and demonstrate, to some extent, the generality of the misinformation effect to a non-visual auditory domain.     

Effects of mothers’ conversation style and receipt of misinformation on children's event reports

Can memory sharing conversations with mothers lead to errors in children's event memory when mothers are exposed to misinformation about what their children experienced and does this effect vary as a function of maternal memory-sharing style? Mothers were exposed to a false suggestion about a non-shared event and then discussed that event with their children. When later interviewed, those children whose mothers were provided this misinformation were likely to wrongly report experiencing activities consistent with the maternal suggestion and embellish their reports of these activities with elaborative detail. Moreover, children whose mothers spoke in a highly elaborative manner were more likely to recall occurrences in line with the maternal suggestion and provided more fictitious narrative detail describing non-occurring-but-suggested information than did children whose mothers used a less elaborative style. These findings suggest that when mothers hold false beliefs about a non-shared event, an elaborative maternal style is associated with an increase in children's false reports reflecting maternal beliefs.