Deryn Strange

A mega-analysis of memory reports from eight peer-reviewed false memory implantation studies

ABSTRACT Understanding that suggestive practices can promote false beliefs and false memories for childhood events is important in many settings (e.g., psychotherapeutic, medical, and legal). The generalisability of findings from memory implantation studies has been questioned due to variability in estimates across studies. Such variability is partly due to false memories having been operationalised differently across studies and to differences in memory induction techniques. We explored ways of defining false memory based on memory science and developed a reliable coding system that we applied to reports from eight published implantation studies (N = 423). Independent raters coded transcripts using seven criteria: accepting the suggestion, elaboration beyond the suggestion, imagery, coherence, emotion, memory statements, and not rejecting the suggestion. Using this scheme, 30.4% of cases were classified as false memories and another 23% were classified as having accepted the event to some degree. When the suggestion included self-relevant information, an imagination procedure, and was not accompanied by a photo depicting the event, the memory formation rate was 46.1%. Our research demonstrates a useful procedure for systematically combining data that are not amenable to meta-analysis, and provides the most valid estimate of false memory formation and associated moderating factors within the implantation literature to date.

Photographs cause false memories for the news

What is the effect on memory when seemingly innocuous photos accompany false reports of the news? We asked people to read news headlines of world events, some of which were false. Half the headlines appeared with photographs that were tangentially related to the event; others were presented without photographs. People saw each headline only once, and indicated whether they remembered the event, knew about it, or neither. Photos led people to immediately and confidently remember false news events. Drawing on the Source Monitoring Framework (Johnson, Hashtroudi, & Lindsay, 1993), we suggest that people often relied on familiarity and other heuristic processes when making their judgments and thus experienced effects of the photos as evidence of memory for the headlines.

False memories in the DRM paradigm: age-related differences in lure activation and source monitoring.

Prior research using the Deese-Roediger-McDermott paradigm has shown that participants are more likely to report the critical lures when long lists are presented. In this experiment, we evaluated two potential explanations for this list-length effect. Ten-year-old children and adults studied 7- or 14-word lists. After recalling each list, participants were then asked to report any other words that they had thought about, but had not reported, during the recall phase. We found that long lists were more likely to activate the critical lure and that short lists did not facilitate source monitoring. On the basis of our findings, we conclude that, for both age groups, the list-length effect was due primarily to list-related differences in activation of the critical lure.

Creating false memories for events that occurred before versus after the offset of childhood amnesia

We examined whether false images and memories for childhood events are more likely when the event supposedly took place during the period of childhood amnesia. Over three interviews, participants recalled six events: five true and one false. Some participants were told that the false event happened when they were 2 years old (Age 2 group), while others were told that it happened when they were 10 years old (Age 10 group). We compared participants’ reports of the false event to their reports of a true event from the same age. Consistent with prior research on childhood amnesia, participants in the Age 10 group were more likely than participants in the Age 2 group to remember their true event and they reported more information about it. Participants in the Age 2 group, on the other hand, were more likely to develop false images and memories than participants in the Age 10 group. Furthermore, once a false image or memory developed, there were no age-related differences in the amount of information participants reported about the false event. We conclude that childhood amnesia increases our susceptibility to false suggestion, thus our results have implications for court cases where early memories are at issue.

Unfair Lineups Make Witnesses More Likely to Confuse Innocent and Guilty Suspects

Eyewitness-identification studies have focused on the idea that unfair lineups (i.e., ones in which the police suspect stands out) make witnesses more willing to identify the police suspect. We examined whether unfair lineups also influence subjects’ ability to distinguish between innocent and guilty suspects and their ability to judge the accuracy of their identification. In a single experiment (N = 8,925), we compared three fair-lineup techniques used by the police with unfair lineups in which we did nothing to prevent distinctive suspects from standing out. Compared with the fair lineups, doing nothing not only increased subjects’ willingness to identify the suspect but also markedly impaired subjects’ ability to distinguish between innocent and guilty suspects. Accuracy was also reduced at every level of confidence. These results advance theory on witnesses’ identification performance and have important practical implications for how police should construct lineups when suspects have distinctive features.

Source confusion influences the effectiveness of the autobiographical IAT

We examined the claim that the autobiographical Implicit Association Test (aIAT) can detect concealed memories. Subjects read action statements (e.g., “break the toothpick”) and either performed the action or completed math problems. They then imagined some of these actions and some new actions. Two weeks later, the subjects completed a memory test and then an aIAT in which they categorized true and false statements (e.g., “I am in front of the computer”) and whether they had or had not performed actions from Session 1. For half of the subjects, the nonperformed statements were actions that they saw but did not perform; for the remaining subjects, these statements were actions that they saw and imagined but did not perform. Our results showed that the aIAT can distinguish between true autobiographical events (performed actions) and false events (nonperformed actions), but that it is less effective, the more that subjects remember performing actions that they did not really perform. Thus, the diagnosticity of the aIAT may be limited.

Emotional Impact Feedback Changes How We Remember Negative Autobiographical Experiences

When people are told that their negative memories are worse than other peoples, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event--stating it was more or less negative compared to other peoples experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memorys characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.

The effect of suggestion on children's recognition memory for seen and unseen details

Abstract The present study examined the effect of three different types of suggestion on childrens recognition memory. Younger (7-year-olds; n=38) and older (11-year-olds; n=47) children listened to a class presentation about China. Three days later, they were interviewed using suggestive questions that were divided into three categories: questions suggesting that details were present when in fact they were not (commission errors), questions suggesting that presented details were absent (omission errors), and questions suggesting that details were presented differently (change errors). The following day, children participated in a recognition-memory task that contained items that referred to information suggested during the suggestive interview. Children in both age groups were more likely to erroneously endorse items involving change errors than they were to endorse items involving commission or omission errors.

Metacognitive and Metamemory Beliefs in the Development and Maintenance of Posttraumatic Stress Disorder

Can metacognition increase trauma sufferers’ risk for developing and maintaining posttraumatic stress disorder (PTSD)? We assessed the role of a range of cognitive and metacognitive belief domains—including metamemory—on PTSD symptoms. Adult participants reported their existing meta/cognitions and lifetime exposure to trauma, then 12 weeks later, they reported meta/cognitions and PTSD symptoms in relation to new trauma exposure since the initial assessment. Participants with more PTSD symptoms held more problematic metacognitions than participants with fewer distress symptoms. Moreover, people who endorsed maladaptive metacognitions before trauma exposure were more likely to experience symptoms of PTSD after exposure. Metacognition predicted the maintenance of elevated PTSD symptoms over the 12-week delay. Our findings support the metacognitive model of PTSD and highlight the importance of metamemory, an understudied factor in PTSD research.

Encoding disorganized memories for an analogue trauma does not increase memory distortion or analogue symptoms of PTSD.

BACKGROUND AND OBJECTIVES Empirical studies with objective measures and control conditions have failed to demonstrate disorganization; yet people tend to self-report disorganization in their trauma narratives, which may have other effects. Thus, we investigated whether a disorganized trauma memory produces more analogue PTSD symptoms and memory distortion, compared to an organized memory. METHODS Participants watched a traumatic film with missing scenes. Some saw the scenes in their correct temporal sequence; others saw a random sequence; thus for some participants we implanted a disorganized memory. We also told some participants to focus on the meaning of the event (conceptual), some on the sensory details (data-driven), and some received no instruction (control). Participants recorded their intrusions for a week. Then, they reported analogue symptoms and we tested their memory for the film and their confidence in what they remembered. RESULTS Analogue symptoms and number of reported intrusions did not differ across conditions, nor did the degree of memory distortion or confidence in those memories. However, participants who self-reported feeling more memory disorganization reported more avoidance symptoms and more memory distortion. LIMITATIONS We did not measure memory for real trauma, nor did we assess for a history of PTSD. Our results may also be restricted to temporal disorganization. CONCLUSIONS Although objective assessments of disorganization do not appear important, peoples feelings regarding the disorganization of their memories not only affect their assessment of the severity of their PTSD symptoms, but also the kinds of memory errors they make.