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.     

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.     

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.     

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.     

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.     

Narrative Skills,Gender, Culture,and Children’s Long-Term Memory Accuracy of a Staged Event

This study examined the extent to which school-aged children’s general narrative skills provide cognitive benefits for accurate remembering or enable good storytelling that undermines memory accuracy. European American and Chinese American 6-year-old boys and girls (N = 114) experienced a staged event in the laboratory and were asked to tell a story from a picture book that accessed their narrative skill. Children were interviewed about the staged event 6 months later to assess memory accuracy. Greater narrative skill when storytelling was associated with decreased free recall and recognition memory accuracy for the staged event. In free recall responses, this effect was driven by an increase in the likelihood that inaccurate details would be included in responses from children with better general narrative skills. For girls only, narrative skill predicted poorer recognition accuracy. Girls were also more language-proficient and provided more correct details in free recall than did boys. Chinese American children were more accurate than European American children when responding to recall prompts due to less frequent provision of incorrect details, particularly in girls. Findings are discussed in light of the roles of socialization in memory-reporting accuracy.     

Both young and older adults discount suggestions from older adults on a social memory test

In the present study, we examined the impacts of participant age and confederate age on social memory processes. During a collaborative recall phase, young and older adult participants were exposed to the erroneous memory reports of a young or an older adult confederate. On a subsequent individual recall test, young and older adult participants were equally likely to incorporate the confederates’ erroneous suggestions into their memory reports, suggesting that participant age had a minimal effect on social memory processes. However, confederate age did have a marked effect: Young adult participants were less likely to incorporate misleading suggestions from older adult confederates and less likely to report “remembering” items suggested by older adult confederates. Critically, older adult participants were also less likely to incorporate misleading information from fellow older adult confederates. Both young and older adult participants discounted older adult confederates’ contributions to a memory test.     

Investigating the variability of memory distortion for an analogue trauma

In this paper, we examine whether source monitoring (SM) errors might be one mechanism that accounts for traumatic memory distortion. Participants watched a traumatic film with some critical (crux) and non-critical (non-crux) scenes removed. Twenty-four hours later, they completed a memory test. To increase the likelihood participants would notice the film's gaps, we inserted visual static for the length of each missing scene. We then added manipulations designed to affect people's SM behaviour. To encourage systematic SM, before watching the film, we warned half the participants that we had removed some scenes. To encourage heuristic SM some participants also saw labels describing the missing scenes. Adding static highlighting, the missing scenes did not affect false recognition of those missing scenes. However, a warning decreased, while labels increased, participants' false recognition rates. We conclude that manipulations designed to affect SM behaviour also affect the degree of memory distortion in our paradigm.     

Forgetting having denied: The “amnesic” consequences of denial

The concept of denial has its roots in psychoanalysis. Denial has been assumed to be effective in blocking unwanted memories. In two experiments, we report that denial has unique consequences for remembering. In our two experiments, participants viewed a video of a theft, and half of the participants had to deny seeing certain details in the video, whereas the other half had to tell the truth. One day later, all participants were given either a source-monitoring recognition or a recall task. In these tasks, they were instructed to indicate (1) whether they could remember talking about certain details and (2) whether they could recollect seeing those details in the video. In both experiments, we found that denial made participants forget that they had talked about these details, while leaving memory for the video itself unaffected. This denial-induced forgetting was evident for both the source-monitoring recognition and recall tests. Furthermore, when we asked participants after the experiment whether they could still not remember talking about these details, those who had to deny were most likely to report that they had forgotten talking about the details. In contrast to a widely held belief, we show that denial does not impair memory for the experienced stimuli, but that it has a unique ability to undermine memory for what has been talked about.     

No Benefit of Eye-Closure Rehearsal in a Unimodal Recognition Memory Test for Word Items

Recent studies have suggested that closing the eyes helps memory retrieval in recall tests for audiovisual clips that contain multimodal information. In two experiments, we examined whether eye-closure improves recognition memory performance for word lists presented unimodally (i.e., visually or aurally). In the encoding phase, participants saw or heard a list of unrelated, meaningful word items. After a fixed retention interval of 1 week (Experiment 1, n = 110) and 5 min (Experiment 2, n = 44), the participants were asked to mentally rehearse the items with their eyes open or closed, and then they performed a recognition test. The results revealed no effect of eye-closure rehearsal on recognition performance. We discuss the possible reasons why no eye-closure benefit was found in recognition memory tests for unrelated word items.     

Now you see it; now you don't: inhibiting recall and recognition of scenes

Postevent misleading information can distort people's memories by altering and adding scenes. But can you also inhibit the retrieval of information from memory? In two studies we show that postevent information can make memory for a scene less accessible. In both studies participants first saw an event (e.g. a restaurant scene displayed in slides, or a drunk‐driving incident shown via a video clip). Later they were shown the same event without a critical scene and were told either to use this to generate a story (Experiment 1) or to imagine the event (Experiment 2). Finally they were tested. Relative to controls, this postevent omission led to fewer people reporting the critical scene in free recall and in recognition. Thus, we demonstrated that it may be possible to inhibit memories. This finding has important implications for eyewitness testimony and the recovered memory debate. Copyright © 2001 John Wiley & Sons, Ltd.     

Confidence–accuracy relations for faces and scenes: Roles of features and familiarity

Using naturalistic scenes, we recently demonstrated that confidence?Caccuracy relations differ depending on whether recognition responses are based on memory for a specific feature or instead on general familiarity: When confidence is controlled for, accuracy is higher for familiarity-based than for feature-based responses. In the present experiment, we show that these results generalize to face recognition. Subjects studied photographs of scenes and faces presented for varying brief durations and received a recognition test on which they (1) indicated whether each picture was old or new, (2) rated their confidence in their response, and (3) indicated whether their response was based on memory for a feature or on general familiarity. For both stimulus types, subjects were more accurate and more confident for their feature-based than for their familiarity-based responses. However, when confidence was held constant, accuracy was higher for familiarity-based than for feature-based responses. These results demonstrate an important similarity between face and scene recognition and show that for both types of stimuli, confidence and accuracy are based on different information.     

Diagnosing criterion-level effects on memory: what aspects of memory are enhanced by repeated retrieval?

Previous research has shown that increasing the criterion level (i.e., the number of times an item must be correctly retrieved during practice) improves subsequent memory, but which specific components of memory does increased criterion level enhance? In two experiments, we examined the extent to which the criterion level affects associative memory, target memory, and cue memory. Participants studied Lithuanian-English word pairs via cued recall with restudy until items were correctly recalled one to five times. In Experiment 1, participants took one of four recall tests and one of three recognition tests after a 2-day delay. In Experiment 2, participants took only recognition tests after a 1-week delay. In both experiments, increasing the criterion level enhanced associative memory, as indicated by enhanced performance on forward and backward cued-recall tests and on tests of associative recognition. An increased criterion level also improved target memory, as indicated by enhanced free recall and recognition of targets, and improved cue memory, as indicated by enhanced free recall and recognition of cues.     

Are valence and social avoidance associated with the memory conformity effect?

Pairs of participants were shown photographs which varied in terms of valence from negative to positive, and two days later, together, they were given a memory recognition test. When the first person responded the second person saw the response. This affected how the second person responded, what is called memory conformity. The memory conformity effect was larger for previously unseen stimuli (fillers) than for previously seen stimuli (targets), and was greatest for those with low scores on a social avoidance measure. While memory for negative (and most arousing) stimuli was most accurate, the memory conformity effect did not differ significantly by the stimulus valence. Implications for theories of memory malleability and for assessing the reliability of memories in a forensic context are discussed.     

An analogue study of the effects of Psychological Debriefing on eyewitness memory

Sixty-one participants from the community participated in a randomised controlled trial of group debriefing to assess the effect of this intervention upon memory for a stressful event. Participants were randomly allocated to one of three groups: debriefing; debriefing with an experimenter confederate present (who supplied three pieces of misinformation to the group regarding the stressful event); and a no-treatment control. All groups were shown a very stressful video and were again reviewed after 1 month. Members of the debriefing group where a confederate provided misinformation were more likely to recall this misinformation as fact than members of the other two groups. The debriefing group was also more accurate in their recall of peripheral content than the confederate group. Across all groups, participants were found to be more accurate at central rather than peripheral recall yet more confident for incorrect memories of the video than correct memories.     

Collaborative remembering of emotional events: the case of Rabin's assassination

Individual and collaborative remembering of the assassination of Israel's Prime Minister, Itzhak Rabin, were compared. In line with previous laboratory findings on memory of neutral stimuli, it was hypothesised that collaborative remembering (three individuals reaching a common response) and nominal remembering (three individual responses pooled together) of the assassination would be more accurate than individual remembering. A total of 146 participants responded (115 individually and 120 in groups of three) to open-ended and multiple-choice questionnaires (among them, 89 responded twice with a week of intertest interval) about Rabin's assassination and the events that preceded and followed it. Data analysis showed that the collaborative responses to the open-ended questionnaire contained more details (both accurate and inaccurate) than the individual responses, and that the responses to the multiple-choice questionnaire were more accurate than the individual responses. However, the collaborative responses contained fewer details (both accurate and inaccurate) than the nominal responses. Responses to the two questionnaires were more accurate on the retest when they followed collaborative rather than individual responses on the original test. The inferiority of the collaborative relative to the nominal remembering was attributed to collaborative inhibition, whereas the positive effect of collaborative remembering on performance on the retest was attributed to the contribution of contextual cues.     

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.     

Collaborative remembering of emotional events: The case of Rabin's assassination

Individual and collaborative remembering of the assassination of Israel's Prime Minister, Itzhak Rabin, were compared. In line with previous laboratory findings on memory of neutral stimuli, it was hypothesised that collaborative remembering (three individuals reaching a common response) and nominal remembering (three individual responses pooled together) of the assassination would be more accurate than individual remembering. A total of 146 participants responded (115 individually and 120 in groups of three) to open-ended and multiple-choice questionnaires (among them, 89 responded twice with a week of intertest interval) about Rabin's assassination and the events that preceded and followed it. Data analysis showed that the collaborative responses to the open-ended questionnaire contained more details (both accurate and inaccurate) than the individual responses, and that the responses to the multiple-choice questionnaire were more accurate than the individual responses. However, the collaborative responses contained fewer details (both accurate and inaccurate) than the nominal responses. Responses to the two questionnaires were more accurate on the retest when they followed collaborative rather than individual responses on the original test. The inferiority of the collaborative relative to the nominal remembering was attributed to collaborative inhibition, whereas the positive effect of collaborative remembering on performance on the retest was attributed to the contribution of contextual cues.     

Phenomenal characteristics of cryptomnesia

Qualitative characteristics of cryptomnesia, or unintentional plagiarism were investigated. In Experiment 1 we compared accurate and inaccurate source attributions in terms of their level of confidence using instructions that did not require a fixed number of responses. Confidence was lower for plagiarised responses than for correct responses. Nevertheless, participants provided high ratings of certainty for a large proportion of their plagiarised responses. In Experiment 2 the phenomenological differences between plagiarised recall and veridical recall were compared by using an adaptation of the memory characteristics questionnaire (Johnson, Foley, Suengas, & Raye, 1988). Correct responses were associated with more experiential detail than plagiarised responses. However, a considerable number of plagiarised responses were accompanied by a confident memory of at least one qualitative characteristic. Results are discussed in terms of the source monitoring framework developed by Johnson, Hashtroudi, and Lindsay (1993).