Inventing stories: Forcing witnesses to fabricate entire fictitious events leads to freely reported false memories

Studies of the forced fabrication effect have shown that participant witnesses are prone to developing false memories for specific items or details that they have been forced to fabricate earlier (e.g., what type of hat someone wore). Building on these earlier findings, the present study assessed whether participants would develop false memories if forced to fabricate entire fictitious events that were more complex and extended in time and involved people, locations, and actions that they had never seen. Participants vehemently resisted fabricating these events, and false memory development over the short term (1-week recognition test) was limited. However, after 8 weeks, participants freely reported their forced fabrications nearly 50% of the time and did so even when they had correctly and publicly rejected them earlier on the 1-week recognition test. This is the first evidence that participant witnesses will freely incorporate into their eyewitness accounts entire fictitious events that they have earlier been forced to fabricate.     

The effect of forced recall on illusory recollection in younger and older adults

The effect of an initial forced recall test on later recall and recognition tests was examined in younger and older adults. Subjects were presented with categorized word lists and given an initial test under standard cued recall instructions (with a warning against guessing) or forced recall instructions (that required guessing); subjects were later given a cued recall test for the original list items. In 2 experiments, initial forced recall resulted in higher levels of illusory memories on subsequent tests (relative to initial cued recall), especially for older adults. Older adults were more likely to say they remembered rather than knew that forced guesses had occurred in the original study episode. The effect persisted despite a strong warning against making errors in Experiment 2. When a source monitoring test was given, older adults had more difficulty than younger adults in identifying the source of items they had originally produced as guesses. If conditions encourage subjects to guess on a first memory test, they are likely to recollect these guesses as actual memories on later tests. This effect is exaggerated in older adults, probably because of their greater source monitoring difficulties. Both dual process and source monitoring theories provide insight into these findings.     

Automatic and intentional processes in children's recognition memory: the reversed misinformation effect

This study investigated the contribution of automatic and intentional memory processes to 5‐ and 6‐year‐old children's suggestible responses in a reversed misinformation paradigm. The temporal order of the conventional eyewitness paradigm was altered such that children were initially presented with a pre‐event narrative containing misinformation that was either read to them or was self‐generated in response to semantic and linguistic cues, and the following day were presented with a witnessed event in the form of a picture story. Children then completed a standard forced‐choice recognition memory test under two instruction conditions. In the inclusion condition children were reminded about the presentations of the pre‐event narrative and the original story and asked to chose the witnessed event item. In the exclusion condition children were instructed to exclude pre‐event suggestions. Suggestibility effects were found with the magnitude of such effects differentially affected by the encoding of misleading suggestions and test instructions. In the exclusion condition, children were more likely to correctly reject suggestions that were ‘self‐generated’. Both automaticity and intentional recollection contributed to children's suggestible responding. Copyright © 2002 John Wiley & Sons, Ltd.     

Assessing the effectiveness of warnings and the phenomenological characteristics of false memories

The phenomenology of false memories was investigated in three experiments in which participants heard two experimenters read lists of items that were related to critical nonpresented items. In Experiments 1, following a recognition memory test, participants rated the phenomenological characteristics of their memories immediately and after a 48-hour delay. False recognition was prevalent and on several dimensions participants rated their true memories as more vivid than their false memories. In Experiments 2 and 3, following the study phase, participants were warned about the phenomenological differences between true and false memories and were instructed to use this information to avoid reporting nonpresented items. This type of warning was ineffective at reducing false recall (Experiment 2) and false recognition (Experiment 3) relative to unwarned participants. Importantly, the inability of explicit warnings to impact illusory recollections demonstrates that the false memories cannot be attributed simply to a criterion shift.     

Assessing the effectiveness of warnings and the phenomenological characteristics of false memories

The phenomenology of false memories was investigated in three experiments in which participants heard two experimenters read lists of items that were related to critical nonpresented items. In Experiments 1, following a recognition memory test, participants rated the phenomenological characteristics of their memories immediately and after a 48-hour delay. False recognition was prevalent and on several dimensions participants rated their true memories as more vivid than their false memories. In Experiments 2 and 3, following the study phase, participants were warned about the phenomenological differences between true and false memories and were instructed to use this information to avoid reporting nonpresented items. This type of warning was ineffective at reducing false recall (Experiment 2) and false recognition (Experiment 3) relative to unwarned participants. Importantly, the inability of explicit warnings to impact illusory recollections demonstrates that the false memories cannot be attributed simply to a criterion shift.     

Does test‐induced priming play a role in the creation of false memories?

We investigated the role of test‐induced priming in creating false memories in the Deese/Roediger‐McDermott (DRM) paradigm, in which subjects study lists of related words (bed, rest, awake) and then falsely recall or recognise a related word (sleep) on a later test. However, in experiments using three different procedures, we found that the number of related words tested prior to the critical word had surprisingly little impact on false recall and recognition. We manipulated the location of the critical item in tests of yes/no recognition, word‐stem cued recall, and part‐set cued recall. We consistently obtained high probabilities of false recall and recognition, but the probability was unaffected by the number of related items presented prior to the test of the critical item. Surprisingly, test‐induced priming of the critical item does not seem to play a large role in this memory illusion.     

The effects of initial testing on false recall and false recognition in the social contagion of memory paradigm

In three experiments, participants studied photographs of common household scenes. Following study, participants completed a category-cued recall test without feedback (Exps. 1 and 3), a category-cued recall test with feedback (Exp. 2), or a filler task (no-test condition). Participants then viewed recall tests from fictitious previous participants that contained erroneous items presented either one or four times, and then completed final recall and source recognition tests. The participants in all conditions reported incorrect items during final testing (a social contagion effect), and across experiments, initial testing had no impact on false recall of erroneous items. However, on the final source-monitoring recognition test, initial testing had a protective effect against false source recognition: Participants who were initially tested with and without feedback on category-cued initial tests attributed fewer incorrect items to the original event on the final source-monitoring recognition test than did participants who were not initially tested. These data demonstrate that initial testing may protect individuals’ memories from erroneous suggestions.     

Derived false memories using a respondent‐type (ReT) procedure

The present investigation used a respondent‐type (ReT) training procedure to generate derived false memories. A one‐to‐many ReT training procedure was implemented in order to establish two stimulus equivalence classes, each consisting of one shape and 24 random words (i.e., Class 1 and Class 2). A partial test for stimulus equivalence with a subset of stimuli from each class followed. Failing an equivalence test resulted in additional ReT training and equivalence testing on new subsets of stimuli. After passing an equivalence test, participants were presented with 12 study‐list words from Class 1 for memorization, followed by a distraction task. Finally, free recall and recognition tests for the study‐list words were implemented. False recall and false recognition were more frequent for nonstudied Class 1 words than for nonstudied Class 2 words. These derived false‐memory effects were more pronounced among those participants exhibiting more training and testing cycles and higher accuracy on stimulus equivalence tests. Furthermore, false recall and false remembering of nonstudied Class 1 words were more frequent for words that had been equivalence‐tested than for words that had not been equivalence‐tested. These results show how responses to contiguous stimuli could produce derived false memories and also highlight the role played by the equivalence test in increasing their emergence.     

Combating Co‐witness contamination: Attempting to decrease the negative effects of discussion on eyewitness memory

Witnesses who discuss an event with others often incorporate misinformation encountered during the discussion into their memory of the event. Two experiments were conducted to establish whether this memory conformity also occurs in the context of an interview and whether it is possible to reduce the effect. Participants viewed a crime‐video which they then discussed with a co‐witness. Some participants were warned they may have been exposed to misinformation during the discussion before all were interviewed individually. In Experiment 1, participants made remember/know judgments about each component of their free recall, and in Experiment 2 they were asked to indicate the source of their memories. Co‐witness information was incorporated into participants' testimony, and this effect could not be significantly reduced using warnings and source‐monitoring instructions. Remember/know judgments may be useful in distinguishing ‘real’ memories from false memories. We make some recommendations regarding the interviewing of witnesses. Copyright © 2009 John Wiley & Sons, Ltd.     

Explorations in the social contagion of memory

Four experiments examined social influence on the development of false memories. We employed the social contagion paradigm: A subject and a confederate see scenes and then later take turns recalling items from the scenes, with the confederate erroneously reporting some items that were not present in the scenes; on a final test, the subject reports these suggested items when instructed to recall only items from the scenes. The first two experiments showed that the social contagion effect persisted when subjects were explicitly warned about the possibility that confederates' responses might induce false memories and when they were tested via source-monitoring tests that explicitly gave the choice of attributing suggested items to the other person. Levels of false recall and recognition increased with the number of times the misleading information was suggested (Experiment 3), and subjects were more likely to incorporate the erroneous responses of an actual confederate on a recognition/source test as compared with those of a simulated confederate (Experiment 4). Collectively, the data support the claim that false memories may be transmitted between people and reveal critical factors that modulate the social contagion of memories.     

The influences of partner accuracy and partner memory ability on social false memories

In this study, we examined whether increasing the proportion of false information suggested by a confederate would influence the magnitude of socially introduced false memories in the social contagion paradigm Roediger, Meade, & Bergman (Psychonomic Bulletin & Review 8:365–371, 2001). One participant and one confederate collaboratively recalled items from previously studied household scenes. During collaboration, the confederate interjected 0 %, 33 %, 66 %, or 100 % false items. On subsequent individual-recall tests across three experiments, participants were just as likely to incorporate misleading suggestions from a partner who was mostly accurate (33 % incorrect) as they were from a partner who was not at all accurate (100 % incorrect). Even when participants witnessed firsthand that their partner had a very poor memory on a related memory task, they were still as likely to incorporate the confederate’s entirely misleading suggestions on subsequent recall and recognition tests (Exp. 2). Only when participants witnessed firsthand that their partner had a very poor memory on a practice test of the experimental task itself were they able to reduce false memory, and this reduction occurred selectively on a subsequent individual recognition test (Exp. 3). These data demonstrate that participants do not always consider their partners’ memory ability when working on collaborative memory tasks.     

Working memory predicts the rejection of false memories

The relationship between working memory capacity (WMC) and false memories in the memory conjunction paradigm was explored. Previous research using other paradigms has shown that individuals high in WMC are not as likely to experience false memories as low-WMC individuals, the explanation being that high-WMC individuals are better able to engage in source monitoring. In the memory conjunction paradigm participants are presented at study with parent words (e.g., eyeglasses, whiplash). At test, in addition to being presented with targets and foils, participants are presented with lures that are composed of previously studied features (e.g., eyelash). It was found that high-WMC individuals had lower levels of false recognition than low-WMC individuals. Furthermore, recall-to-reject responses were analysed (e.g., “I know I didn't see eyelash because I remember seeing eyeglasses”) and it was found that high-WMC individuals were more likely to utilise this memory editing strategy, providing direct evidence that one reason that high-WMC individuals are not as prone to false memories is because they are better able to engage in source monitoring.     

Correcting socially introduced false memories: The effect of re-study

This study examined whether participants could utilize re-study and perceptual elaboration to correct erroneous suggestions from their partner in the social contagion of memory paradigm. Participants studied household scenes and then collaboratively recalled the scenes with a confederate who interjected erroneous items. Before completing subsequent individual recall and recognition tests, participants were allowed to re-study the original items and/or to generate perceptual details of the items. Across two experiments, participants who re-studied the original material were less likely to incorporate the confederate's misleading suggestions. Re-study reduced false recall and recognition and increased veridical recall and recognition (Experiment 1) and the effect was especially pronounced with longer re-study episodes (Experiment 2). Items generated on the perceptual elaboration test offered no corrective benefit above and beyond the effects of re-study. These data demonstrate that participants can rely on self-initiated correction processes engaged during re-study to reduce socially suggested false memories.     

Eliciting and comparing false and recovered memories: an experimental approach

We describe an experimental paradigm designed to elicit both recovered and false memories in the laboratory. All participants saw, on a video screen, three critical categorized lists of words mixed in randomly with eighteen filler categorized lists. Those in the blocking condition then had several paper‐and‐pencil tasks that involved only the 18 non‐critical filler lists. An uncued recall test was then given, asking participants to recall all the lists they originally saw on the video screen. Finally, there was a cued recall test that provided category cues for the three critical lists. Substantial memory blocking of critical lists on the uncued test and recovery on the cued recall test was observed in all three experiments. In Experiments 2 and 3, many false and recovered memories were elicited on the cued recall test by including cues for the three critical (forgotten) lists, plus cues for three lists that had never been presented. False memories were distinguishable from truly recovered memories in cued recall by ‘know’ versus ‘remember’ judgements, and by confidence ratings; accurately recovered memories were associated with higher confidence. False and recovered memories could not be discriminated based on recall latency. The results repeatedly show powerful effects of memory blocking and recovery. We also show that recovered and false memories can be elicited within a single experimental procedure, and there may be unique characteristics of each. Although we urge caution in generalizing to false and recovered memories of trauma, we suggest that variations of our comparative memory paradigm may be useful for learning about such phenomena. Copyright © 2003 John Wiley & Sons, Ltd.     

The ironic effect of guessing: increased false memory for mediated lists in younger and older adults

Younger and older adults studied lists of words directly (e.g., creek, water) or indirectly (e.g., beaver, faucet) related to a nonpresented critical lure (CL; e.g., river). Indirect (i.e., mediated) lists presented items that were only related to CLs through nonpresented mediators (i.e., directly related items). Following study, participants completed a condition-specific task, math, a recall test with or without a warning about the CL, or tried to guess the CL. On a final recognition test, warnings (vs. math and recall without warning) decreased false recognition for direct lists, and guessing increased mediated false recognition (an ironic effect of guessing) in both age groups. The observed age-invariance of the ironic effect of guessing suggests that processes involved in mediated false memory are preserved in aging and confirms the effect is largely due to activation in semantic networks during encoding and to the strengthening of these networks during the interpolated tasks.     

Stereotype threat can reduce older adults' memory errors

Stereotype threat often incurs the cost of reducing the amount of information that older adults accurately recall. In the current research, we tested whether stereotype threat can also benefit memory. According to the regulatory focus account of stereotype threat, threat induces a prevention focus in which people become concerned with avoiding errors of commission and are sensitive to the presence or absence of losses within their environment. Because of this, we predicted that stereotype threat might reduce older adults' memory errors. Results were consistent with this prediction. Older adults under stereotype threat had lower intrusion rates during free-recall tests (Experiments 1 and 2). They also reduced their false alarms and adopted more conservative response criteria during a recognition test (Experiment 2). Thus, stereotype threat can decrease older adults' false memories, albeit at the cost of fewer veridical memories, as well.     

Serial position-dependent false memory effects*

ABSTRACT

Evidence for false recognition within seconds of encoding suggests that semantic-associative influences are not restricted to long-term memory, consistent with unitary memory accounts but contrary to dual store models. The present study sought further relevant evidence using a modified free recall converging associates task where participants studied 12-item lists composed of 3 semantically distinct quartets (sublists) related to a separate, non-presented theme word (i.e., words 1–4/theme1, 5–8/theme2, and 9–12/theme3). This list construction permits assessment of false recall errors from each sublist, and, particularly, the primacy and recency sublists that have been linked to long- and short-term memory stores. Experiment 1 tested immediate free recall for items. Associative false memories were evident from all sublists, however, significantly less so from the recent sublist, which also showed the highest levels of veridical memory. By inserting a brief (3?s) distractor prior to recall, Experiment 2 selectively reduced veridical memory and increased false memory for the recent sublist while leaving the primacy sublist unaffected. These recall results converge with prior evidence indicating the immediacy of false recognition, and can be understood within a unitary framework where the differential availability of verbatim features and gist-based cues affect memory for primacy and recency sublists.     

The effect of memory schemata on memory and the phenomenological experience of naturalistic situations

Two experiments document the effect of memory schemata in naturalistic situations. Participants in both experiments watched a short videotaped lecture in which the instructor enacted several schema‐consistent actions (e.g. writing on a whiteboard) and schema‐inconsistent actions (e.g. smoking a cigarette). Following the videotaped lecture, participants completed a recognition test and rated the phenomenological content of their memories. In both experiments, memory was more accurate for schema‐inconsistent actions than for schema‐consistent actions. Participants also indicated that their memories of schema‐inconsistent actions were more vivid than schema‐consistent actions. Interestingly, in Experiment 2, the false memory rate for typical items increased across both 48‐hour and one week retention intervals. These results have important implications for the processes of normal human memory in everyday situations. Copyright © 2002 John Wiley & Sons, Ltd.     

Everyday‐like memory for objects in ageing and Alzheimer's disease assessed in a visually complex environment: The role of executive functioning and episodic memory

To investigate everyday memory, more and more studies rely on virtual‐reality applications to bridge the gap between in situ approaches and laboratory settings. In this vein, the present study was designed to assess everyday‐like memory from the virtual reality‐based Human Object Memory for Everyday Scenes (HOMES) test (Sauzéon et al., 2012 , Exp. Psychol., 59, 99) in ageing and in Alzheimer's disease (AD). Two aims motivated this study: the first was to assess multiple processes of episodic memory (EM) functioning embedded within contexts closely related to real life in ageing and AD using the multi‐trial free‐recall paradigm, and the second aim was to evaluate the mediating effects of executive functioning (EF), EM, and subjective memory complaints (SMCs) on age differences in the HOMES measures and in AD. To this end, the HOMES test and neurocognitive tests of EF and EM were administered to 23 younger adults, 23 older adults, and 16 patients with AD. The results were: firstly, compared to young adults, elderly adults presented only free‐recall decline that almost disappeared in recognition condition whereas AD patients exhibited a poor clustering, learning, and recognition performance, and also a high amount of false recognition; secondly, age differences as well as AD related deficits on the HOMES test were mediated by both memory and EF measure while those observed on false memory indices were only mediated by EM measure; thirdly, the HOMES indices are related to SMCs even when episodic or EF measures are controlled. Overall, the results supported the fact that the VR‐based memory test is an appropriate device to capture age‐related differences as well as the AD effect with respect to both in situ and laboratory settings.