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.     

Social contagion of memory

We report a new paradigm for studying false memories implanted by social influence, a process we call the social contagion of memory. A subject and confederate together saw six common household scenes (e.g., a kitchen) containing many objects, for either 15 or 60 sec. During a collaborative recall test, the 2 subjects each recalled six items from the scenes, but the confederate occasionally made mistakes by reporting items not from the scene. Some intrusions were highly consistent with the scene schema (e.g., a toaster) while others were less so (e.g., oven mitts). After a brief delay, the individual subject tried to recall as many items as possible from the six scenes. Recall of the erroneous items suggested by the confederate was greater than in a control condition (with no suggestion). Further, this social contagion effect was greater when the scenes were presented for less time (15 sec) and when the intruded item was more schema consistent (e.g., the toaster). As with other forms of social influence, false memories are contagious; one person’s memory can be infected by another person’s errors.     

Ageing stereotypes influence the transmission of false memories in the social contagion paradigm

ABSTRACT

These experiments are the first to investigate the impact of confederate accuracy, age, and age stereotypes in the social contagion of memory paradigm. Across two experiments, younger participants recalled household scenes with an actual (Experiment 1) or virtual (Experiment 2), older or younger confederate who suggested different proportions (0%, 33% or 100%) of false items during collaboration. In Experiment 2, positive and negative age stereotypes were primed by providing bogus background information about our older confederate before collaboration. Across both experiments, if confederates suggested false items participants readily incorporated these into their own memory reports. In Experiment 1, when no age stereotype was primed, participants adopted similar proportions of false items from younger and older confederates. Importantly, in Experiment 2, when our older confederate was presented in terms of negative ageing stereotypes, participants reported less false items and were better able to correctly identify the source of those false items.     

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.     

Social Contagion in Competitors Versus Cooperators

The current study examined social contagion—or the spreading of memories from individual to individual—in two different social contexts: Competition and Cooperation. Participants were provided with words (Experiments 1A and 1B) or scenes (Experiment 2) to study. After study, participants were randomly divided: Half were given a competitive context, and the other half, a cooperative context. Then, in the paired recall phase, each participant took turns with a confederate partner in recalling the previously studied items. On a subsequent test, participants had to report the items that were recalled on the pair recall phase, in addition to who had recalled that item. The results showed that competitors, as compared with cooperators, were more likely to focus on other people's memories, and surprisingly, the same difference obtained for false memories. Essentially, people who are primed with a competitive context were more easily ‘infected’ by memories, true or false. Copyright © 2015 John Wiley & Sons, Ltd.     

Discounting input from older adults: the role of age salience on partner age effects in the social contagion of memory

Three experiments examined the impact of partner age on the magnitude of socially suggested false memories. Young participants recalled household scenes in collaboration with an implied young or older adult partner who intentionally recalled false items. In Experiment 1, participants were presented with only the age of their partner (low age-salience context); in Experiment 2, participants were presented with the age of their partner along with a photograph and biographical information about their partner (high age-salience context); in Experiment 3, age salience was varied within the same experiment. Across experiments, participants in both the low age-salience and high age-salience contexts incorporated their partners’ misleading suggestions into their own subsequent recall and recognition reports, thus demonstrating social contagion with implied partners. Importantly, the effect of partner age differed across conditions. Participants in the high age-salience context were less likely to incorporate misleading suggestions from older adult partners than from young adult partners, but participants in the low age-salience context were equally likely to incorporate suggestions from young and older adult partners. Participants discount the memory of older adult partners only when age is highly salient.     

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.     

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.     

Valence and the development of immediate and long-term false memory illusions

Across five experiments we examined the role of valence in children's and adults’ true and false memories. Using the Deese/Roediger-McDermott paradigm and either neutral or negative-emotional lists, both adults’ (Experiment 1) and children's (Experiment 2) true recall and recognition was better for neutral than negative items, and although false recall was also higher for neutral items, false recognition was higher for negative items. The last three experiments examined adults’ (Experiment 3) and children's (Experiments 4 and 5) 1-week long-term recognition of neutral and negative-emotional information. The results replicated the immediate recall and recognition findings from the first two experiments. More important, these experiments showed that although true recognition decreased over the 1-week interval, false recognition of neutral items remained unchanged whereas false recognition of negative-emotional items increased. These findings are discussed in terms of theories of emotion and memory as well as their forensic implications.     

Recall accuracy and illusory memories: when more is less

In two experiments it was revealed that manipulations that increased recall of studied list items also increased false recall of theme-related, critical nonpresented words. In Experiment 1 subjects listened to a series of short word lists, each containing items associatively related to a theme, while engaging in either semantic or nonsemantic processing. On an immediate free recall test semantic processors demonstrated greater correct recall as well as more illusory memories of critical nonpresented items than nonsemantic processors. In Experiment 2, the short study lists were combined to form longer lists that were presented either blocked by theme or in a random presentation order. Retention interval was also varied as participants were tested either immediately, one week after, or three weeks after the study phase. Presenting the target items in a blocked, as opposed to random, format increased recall accuracy, but this was at the expense of a higher intrusion rate for theme-consistent items. Interestingly, the level of false memories was not affected by retention interval even though typical decrements in the recall of study items were observed over time. The results of these experiments highlight the persistence of the false memory effect, as well as pointing to several factors, primarily semantic processing, that may lead to the creation of false memories. Interpretations are offered within the theoretical frameworks of source monitoring and fuzzy trace theory.     

The effects of social pressure on false memories

The present experiments were designed to examine the effects of social pressure on false memories. Participants studied lists created to elicit false memories and then worked in conjunction with virtual confederates on a recognition memory task. In Experiment 1, participants worked with one or two confederates to complete multiple study-test trials. On the group tests, participants were implicitly pressured to recognize words that did not appear on the studied lists. Experiment 2 was implemented similarly, but utilized a presumably more difficult recognition test involving one long study phase followed by one long test phase. After the purported group tests in both experiments, participants completed surprise individual recognition tests. In both experiments, social pressure influenced participants' responses on group recognition tests and subsequent individual recognition tests. Furthermore, the results indicated that social pressure affected both veridical memories and false memories.     

Changing the criterion for memory conformity in free recall and recognition

People's responses during memory studies are affected by what other people say. This memory conformity effect has been shown in both free recall and recognition. Here we examine whether accurate, inaccurate, and suggested answers are affected similarly when the response criterion is varied. In the first study, participants saw four pictures of detailed scenes and then discussed the content of these scenes with another participant who saw the same scenes, but with a couple of details changed. Participants were either told to recall everything they could and not to worry about making mistakes (lenient), or only to recall items if they were sure that they were accurate (strict). The strict instructions reduced the amount of inaccurate information reported that the other person suggested, but also reduced the number of accurate details recalled. In the second study, participants were shown a large set of faces and then their memory recognition was tested with a confederate on these and fillers. Here also, the criterion manipulation shifted both accurate and inaccurate responses, and those suggested by the confederate. The results are largely consistent with a shift in response criterion affecting accurate, inaccurate, and suggested information. In addition we varied the level of secrecy in the participants’ responses. The effects of secrecy were complex and depended on the level of response criterion. Implications for interviewing eyewitnesses and line-ups are discussed.     

Changing the criterion for memory conformity in free recall and recognition

People's responses during memory studies are affected by what other people say. This memory conformity effect has been shown in both free recall and recognition. Here we examine whether accurate, inaccurate, and suggested answers are affected similarly when the response criterion is varied. In the first study, participants saw four pictures of detailed scenes and then discussed the content of these scenes with another participant who saw the same scenes, but with a couple of details changed. Participants were either told to recall everything they could and not to worry about making mistakes (lenient), or only to recall items if they were sure that they were accurate (strict). The strict instructions reduced the amount of inaccurate information reported that the other person suggested, but also reduced the number of accurate details recalled. In the second study, participants were shown a large set of faces and then their memory recognition was tested with a confederate on these and fillers. Here also, the criterion manipulation shifted both accurate and inaccurate responses, and those suggested by the confederate. The results are largely consistent with a shift in response criterion affecting accurate, inaccurate, and suggested information. In addition we varied the level of secrecy in the participants' responses. The effects of secrecy were complex and depended on the level of response criterion. Implications for interviewing eyewitnesses and line-ups are discussed.     

Part-set cuing of false memories

Part-set cuing inhibition describes the common finding that re-presenting items from a word list can reduce subjects’ overall recall performance for studied items. Do part-set cuing effects occur for false memories as well? In the present experiments, subjects studied lists of words drawn from Roediger and McDermott (1995). After studying each list, subjects completed math problems and then recalled the list items either with or without accompanying list cues. In Experiment 1, the recall cues consisted of items drawn randomly from the original list. In Experiment 2, an additional type of cued recall task was added in which the even numbered list items were used as cues. Taken together, these experiments demonstrate robust part-set cuing effects for critical nonpresented items. In addition, they show that whereas recall of critical words is reduced by the presence of cues at test, retrieval cues do not affect critical words and studied words in exactly the same manner.     

Age differences in collaborative memory: the role of retrieval manipulations

In two experiments, we examined age differences in collaborative inhibition (reduced recall in pairs of people, relative to pooled individuals) across repeated retrieval attempts. Younger and older adults studied categorized word lists and were then given two consecutive recall tests and a recognition test. On the first recall test, the subjects were given free-report cued recall or forced-report cued recall instructions (Experiment 1) or free recall instructions (Experiment 2) and recalled the lists either alone or in collaboration with another subject of the same age group. Free-report cued recall and free recall instructions warned the subjects not to guess, whereas forcedreport cued recall instructions required them to guess. Collaborative inhibition was obtained for both younger and older adults on initial tests of free-report cued recall, forced-report cued recall, and free recall, showing that the effect generalizes across several tests for both younger and older adults. Collaborative inhibition did not persist on subsequent individual recall or recognition tests for list items. Older adults consistently falsely recalled and recognized items more than did younger adults, as had been found in previous studies. In addition, prior collaboration may exaggerate older adults’ tendency toward higher false alarms on a subsequent recognition test, but only after a free recall test. The results provide generality to the phenomenon of collaborative inhibition and can be explained by invoking concepts of strategy disruption and source monitoring.     

Presentation modality affects false memory

Roediger and McDermott (1995) rejuvenated interest in Deese’s (1959) paradigm for producing reliable intrusions and false alarms. Using this paradigm in three experiments, we demonstrated that visual study presentation dramatically reduces the rate of false memories. Only auditory study presentation resulted in equal production of studied and critical items. Correct recall and recognition were unaffected. The suggestion that visual presentation provides a means for discriminating between false and true memories was supported by Experiment 3: Pleasantness rating of study items significantly reduced the creation of false memories regardless of modality.     

Episodic generation can cause semantic forgetting: Retrieval-induced forgetting of false memories

In two experiments, we tested whether false recognition and false recall were prone to retrieval-induced forgetting, using the retrieval practice paradigm (Anderson, Bjork, & Bjork, 1994). Participants encoded lists of cue-target word pairs associated with a nonpresented, critical theme word and then engaged in retrieval practice for half of the word pairs from half of the lists. As expected, unpracticed targets from practiced lists were recognized (Experiment 1) and recalled (Experiment 2) less well than those from unpracticed lists. In addition, false recognition and false recall of critical items associated with practiced lists was lower than false recognition and false recall of items associated with unpracticed lists. We argue that false memories are prone to inhibitory mechanisms engendered by the retrieval practice paradigm. The results are consistent with the claim that semantically activated critical themes interfere with the episodic retrieval of list words and that inhibition decreases the activation level of these interfering memory representations during retrieval practice.     

Social influence and children's event recall and suggestibility

The present study sheds light on interactions between cognitive and social factors affecting children's memory performance and suggestibility in event recall tasks. We examined 251 children, aged 8, 9 and 10 years, and applied a well-known paradigm from social psychology, that is, the social influence of misleading questions was experimentally manipulated through the presence and answering behaviour of an adult confederate. Children's answers about the content of a previously watched film to misleading questions, their accurate statements in their subsequent free recall, as well as performance in a recognition test were assessed. The design also included two control conditions, one in which children answered misleading questions without an adult confederate, and a second one in which no misleading interview was administered but only free recall and recognition. The results document large recall and suggestibility differences between the conditions. Participants of the strong social influence condition answered more conformably to misleading questions and showed a larger effect of memory contagion in recognition. Moreover, there were strong age-related increases in the ability to rely on one's own recollection rather than parroting the confederate's answers. Strong social influence also differentially affected the occurrence of false statements in free recall and errors in the recognition test depending on the children's age.