The effects of repeatedly recalling a traumatic event on eyewitness memory and suggestibility

ABSTRACT

The aims of this study were to examine the effects of repeatedly recalling a traumatic event on recall performance and eyewitness suggestibility. We also investigated whether these effects were moderated by the type of details recalled and the completeness of retrieval. Participants watched a video depicting a fatal car accident and were randomly allocated to one of four conditions in which they: (1) repeatedly recalled the traumatic (central) details of the event only (trauma-focused); (2) repeatedly recalled the non-traumatic (peripheral) details of the event only (non-trauma focused); (3) repeatedly recalled the entire video (complete); or (4) did not recall the video at all (no-recall control). Results indicated that repeated complete recall was beneficial for memory retention of the entire traumatic event and that, in general, trauma-related (central) post-event information (PEI) was less likely to be reported than trauma-unrelated (peripheral) PEI. It was also found that repeated trauma-focused recall increased trauma-related confabulations. These results not only illustrate the value of repeated complete recall to best preserve the integrity of eyewitness memory, but, perhaps more critically, warn of the dangers of repeatedly questioning witnesses specifically about the central or traumatic details of an event.     

The effects of varied retrieval cues on reminiscence in eyewitness memory

Eyewitnesses sometimes recall things at later interviews that they did not recall at previous interviews (reminiscence). When these cases are argued in the courtroom, attorneys may claim (and judges may warn jurors) that eyewitnesses who provide reminiscences are necessarily inaccurate witnesses. Consequently, their testimony may be prematurely discredited or dismissed. We examined here the role of varying the retrieval cues across interviews to account for reminiscence. Participants watched a videotaped mock crime and were tested for recall on two occasions using the same or different cues. Results supported the hypothesis that varying retrieval cues increases the amount of reminiscence. Furthermore, nearly all participants exhibited some reminiscence. Finally, reminiscence was not significantly correlated with overall accuracy of testimony. These findings suggest that many of the assumptions underlying legal tactics and judges' instructions regarding reminiscent inconsistencies are erroneous. Copyright © 2006 John Wiley & Sons, Ltd.     

Intended and unintended effects of explicit warnings on eyewitness suggestibility: Evidence from source identification tests

Previous studies have shown that source identification (ID) tests reduce, and in some cases eliminate, eyewitness suggestibility errors. The present study showed that the suggestibility errors participants committed on a source ID test were further reduced when they were given the explicit postwarning that the experimenter was trying to trick them. These postwarnings reduced suggestibility to the same extent as prewarnings, and they did so for both once and repeatedly suggested items. In addition, the benefits of the pre- and postwarnings persisted when participants were retested 1 week later, but only if the suggestions had been repeated. For once-suggested items, the warning had the unintended effect of improving old/new recognition of the suggested information at retest, an effect that offset the improvements in source discrimination accuracy conferred by the warning. The advantages of using source ID tests for investigating group differences in eyewitness suggestibility are discussed.     

A temporal discriminability account of children's eyewitness suggestibility

Children's suggestibility is typically measured using a three‐stage ‘event–misinformation–test’ procedure. We examined whether suggestibility is influenced by the time delays imposed between these stages, and in particular whether the temporal discriminability of sources (event and misinformation) predicts performance. In a novel approach, the degree of source discriminability was calculated as the relative magnitude of two intervals (the ratio of event–misinformation and misinformation–test intervals), based on an adaptation of existing ‘ratio‐rule’ accounts of memory. Five‐year‐olds (n =150) watched an event, and were exposed to misinformation, before memory for source was tested. The absolute event–test delay (12 versus 24 days) and the ‘ratio’ of event–misinformation/misinformation–test intervals (11:1, 3:1, 1:1, 1:3 and 1:11) were manipulated across participants. The temporal discriminability of sources, measured by the ratio, was indeed a strong predictor of suggestibility. Most importantly, if the ratio was constant (e.g. 18/6 versus 9/3 days), performance was remarkably similar despite variations in absolute delay (e.g. 24 versus 12 days). This intriguing finding not only extends the ratio‐rule of distinctiveness to misinformation paradigms, but also serves to illustrate a new empirical means of differentiating between explanations of suggestibility based on interference between sources and disintegration of source information over time.     

Talking about visually perceived events: Communication effects on eyewitness memory

Communicators' tuning of a message about a social target to their audience's evaluation can shape their representation of the target. This audience‐tuning effect has been demonstrated with ambiguous text passages as input material. We examined whether the effect also occurs when communicators learn about the target's behaviours from visual (nonverbal) input material. In Experiment 1, participants watched a soundless video depicting ambiguous behaviours of a target, described the video to an audience who liked (vs. disliked) the target, and subsequently recalled the video. Both message and recall were biased towards the audience's judgement. In Experiment 2, the video depicted a forensically relevant event, specifically ambiguous behaviours of two persons involved in a bar brawl. Participants tuned their event retellings to their audience's responsibility judgement and remembered the event accordingly. In both experiments, the effect of the audience's judgement on recall was statistically mediated by the extent to which the message was tuned to the audience. The more participants experienced a shared reality with their audience the stronger was the message‐recall correlation (Experiment 2). We conclude that the audience‐tuning effect for visually perceived information depends on the communicators' creation of a shared reality with their audience. Copyright © 2011 John Wiley & Sons, Ltd.     

Mechanisms of eyewitness suggestibility: tests of the explanatory role hypothesis

In a recent paper, Chrobak and Zaragoza (Journal of Experimental Psychology: General, 142(3), 827–844, 2013) proposed the explanatory role hypothesis, which posits that the likelihood of developing false memories for post-event suggestions is a function of the explanatory function the suggestion serves. In support of this hypothesis, they provided evidence that participant-witnesses were especially likely to develop false memories for their forced fabrications when their fabrications helped to explain outcomes they had witnessed. In three experiments, we test the generality of the explanatory role hypothesis as a mechanism of eyewitness suggestibility by assessing whether this hypothesis can predict suggestibility errors in (a) situations where the post-event suggestions are provided by the experimenter (as opposed to fabricated by the participant), and (b) across a variety of memory measures and measures of recollective experience. In support of the explanatory role hypothesis, participants were more likely to subsequently freely report (E1) and recollect the suggestions as part of the witnessed event (E2, source test) when the post-event suggestion helped to provide a causal explanation for a witnessed outcome than when it did not serve this explanatory role. Participants were also less likely to recollect the suggestions as part of the witnessed event (on measures of subjective experience) when their explanatory strength had been reduced by the presence of an alternative explanation that could explain the same outcome (E3, source test + warning). Collectively, the results provide strong evidence that the search for explanatory coherence influences people’s tendency to misremember witnessing events that were only suggested to them.     

Historical background to suggestibility: How interrogative suggestibility differs from other types of suggestibility

This paper reviews the literature on suggestibility and it is argued that ‘interrogative suggestibility’ bears little resemblance to traditional types of suggestibility and requires a separate model of understanding. The distinguishing features of interrogative suggestibility are: (i) it involves a questioning procedure within a closed social interaction; (ii) the questions are mainly concerned with past experiences and events; and (iii) it has a strong ‘uncertainty’ component related to cognitive functioning.     

Alcohol intoxication impairs eyewitness memory and increases suggestibility: Two field studies

Two field studies tested the effect of alcohol intoxication on memory for a live interaction at immediate, delayed, and repeated testing. In Study 1 (N = 86), one researcher presented bar tenants with (misleading) questions regarding a preceding interaction with another researcher. One week later, participants' memory was tested again. Study 2 (N = 189) added a delayed‐testing only condition. We hypothesized intoxication to impair memory and enhance suggestibility and explored whether time of testing affected the outcome on these variables. In Study 1, intoxication reduced completeness and increased suggestibility. In Study 2, intoxication reduced completeness and increased suggestibility in delayed‐only and repeated testing, compared with immediate testing. Sober participants benefited from repeated testing in Study 2, but not Study 1. Findings lend support for consolidation and decay theory and suggest that immediate (intoxicated) testing is preferable over delayed‐only testing. Findings provide little support for alcohol myopia theory.     

The dark side of testing memory: repeated retrieval can enhance eyewitness suggestibility

Eyewitnesses typically recount their experiences many times before trial. Such repeated retrieval can enhance memory retention of the witnessed event. However, recent studies (e.g., Chan, Thomas, & Bulevich, 2009) have found that initial retrieval can exacerbate eyewitness suggestibility to later misleading information--a finding termed retrieval-enhanced suggestibility (RES). Here we examined the influence of multiple retrieval attempts on eyewitness suggestibility to subsequent misinformation. In four experiments, we systematically varied the number of initial tests taken (between zero and six), the delay between initial testing and misinformation exposure (~30 min or 1 week), and whether initial testing was manipulated between- or within-subjects. University undergraduate students were used as participants. Overall, we found that eyewitness suggestibility increased as the number of initial tests increased, but this RES effect was qualified by the delay and by whether initial testing occurred in a within- or between-subjects manner. Specifically, the within-subjects RES effect was smaller than the between-subjects RES effect, possibly because of the influence of retrieval-induced forgetting/facilitation (Chan, 2009) when initial testing was manipulated within subjects. Moreover, consistent with the testing effect literature (Roediger & Karpicke, 2006), the benefits of repeated testing on later memory were stronger after a 1-week delay than after a 30-min delay, thus reducing the negative impact of RES in long-term situations. These findings suggest that conditions that are likely to occur in criminal investigations can either increase (repeated testing) or reduce (delay) the influence of RES, thus further demonstrating the complex relationship between eyewitness memory and repeated retrieval.     

Memory states and memory tasks: an integrative framework for eyewitness memory and suggestibility

An integrative framework (IMP) is presented which depicts performance in eyewitness suggestibility experiments as the participants' solutions of memory tasks, depending on (a) a specified task-relevant memory base and (b) the participants' perception of the memory task. Three theoretical explanations of the effect of misleading post-event information are reinterpreted and reduced to one single core: individuals answer test questions while assuming the consistency of event and post-event information. The impact of such consistency assumptions (a) is demonstrated in a first experiment, where the usual misinformation effect obtained with the Loftus standard test procedure disappeared when the participants' consistency assumptions were destroyed prior to testing, and (b) manifests itself in a qualitative analysis of individual processing strategies for discrepancies between details. Experiment 2, employing methodological innovations suggested by IMP, examined the memory base and found no evidence for memory impairment or misattributions of post-event details to the witnessed scene. However, a follow-up study conducted four and a half months later revealed a strong tendency for such misattributions which might indicate long-term integration of information.     

The effects of interacting in repeated events on children's eyewitness memory and source monitoring

Accurate eyewitness memory of an event may be affected by exposure to and degree of involvement with other related events. In this study, we investigated whether interacting in a related video event affected children's accounts of a real-life target event, and whether interacting in the target event affected memory for different details within the target event. Four-, 6-, and 9-year-old children interacted with an adult who made a puppet. Half of the children in each age group also interacted with a video of a similar event (interactive condition) and half sat and watched the video without interacting (watch condition). When asked non-misleading questions a week later, children in the interactive condition confused the two events more than those in the watch condition. The 4-year-olds in the interactive condition reported a higher rate of confusions in free recall than the 4-year-olds in the watch condition. There were no effects of interaction on responses to misleading questions. The 6- and 9-year-olds were more accurate at answering questions related to actions they themselves had performed than actions performed by the experimenter, although this pattern was reversed for the 4-year-olds. The results are discussed in terms of children's eyewitness memory. © 1998 John Wiley & Sons, Ltd.     

Knowledge matters: Anchoring effects are moderated by knowledge level

Previous research into the relationship between knowledge level and anchoring effects has led to mixed conclusions. This paper presents four studies that used a diverse set of stimuli and paradigms to further investigate this relationship. In Study 1, greater knowledge was associated with smaller anchoring effects—both when knowledge was measured using subjective self‐assessments and when using an objective knowledge measure. In Study 2, participants from the USA and India tended to exhibit smaller anchoring effects when answering questions about their own country as compared with questions about the other country. In Study 3, higher knowledge was associated with smaller anchoring effects when examined at an idiographic level. Finally, in Study 4, providing participants with information designed to increase their knowledge led to a decrease in anchoring effects. The consistency of the results across our four studies provides evidence that anchoring effects are moderated by knowledge level in many situations. Copyright © 2012 John Wiley & Sons, Ltd.     

Some effects of alcohol on eyewitness memory

Male volunteers (N = 120) in small groups of 5 to 10 watched a staged theft involving live actors. Some (n = 47) were under the influence of alcohol (average blood alcohol level of .10) at the time. Some subjects (n = 58) were interviewed immediately after the event, and all were interviewed 1 week later. The delayed interview included the presentation of a photospread that either did or did not contain the picture of the "thief." Alcohol suppressed the amount recalled during the immediate interview and both the amount and accuracy of recall after the 1-week delay. Alcohol had no influence on the ability of witnesses to recognize the thief's picture. When the thief's picture was not present in the photospread, however, alcohol increased the rate of false identifications. An immediate interview substantially improved the amount of information subjects were able to recall 1 week later.     

The effects of repeated experience on children's suggestibility

The effect of suggestive questions on 3- to 5-year-old and 6- to 8-year-old children's recall of the final occurrence of a repeated event was examined. The event included fixed (identical) items as well as variable items where a new instantiation represented the item in each occurrence of the series. Relative to reports of children who participated in a single occurrence, children's reports about fixed items of the repeated event were more accurate and less contaminated by false suggestions. For variable items, repeated experience led to a decline in memory of the specific occurrence; however, there was no increase in susceptibility to suggestions about details that had not occurred. Most errors after repeated experience were intrusions of details from nontarget occurrences. Although younger children and children who were interviewed a while after the event were more suggestible, respectively, than older children and those interviewed soon after the event, repeated experience attenuated these effects.     

Social demand characteristics in children's and adults' eyewitness memory and suggestibility: the effect of different interviewers on free recall and recognition

Shortly after viewing a video of a theft, 5‐ and 7‐year‐old children and adults were interviewed with free recall and either misleading or unbiased‐leading questions. After a 2‐day delay, participants were interviewed with free recall and recognition questions administered by either the same or a different interviewer. Results from day 1 replicate previous findings with levels of recall and resistance to suggestibility increasing with age. Counter to predictions, correct recognition performance on day 2 was greater for some participants interviewed by the same as opposed to a different interviewer, and incorrect recognition was greater for all groups of participants for those interviewed by a different as opposed to the same interviewer. Results are discussed in terms of the role of context dependence on memory performance. Copyright © 2000 John Wiley & Sons, Ltd.     

Attentional focus affects how events are segmented and updated in narrative reading

Readers generate situation models representing described events, but the nature of these representations may differ depending on the reading goals. We assessed whether instructions to pay attention to different situational dimensions affect how individuals structure their situation models (Exp. 1) and how they update these models when situations change (Exp. 2). In Experiment 1, participants read and segmented narrative texts into events. Some readers were oriented to pay specific attention to characters or space. Sentences containing character or spatial-location changes were perceived as event boundaries—particularly if the reader was oriented to characters or space, respectively. In Experiment 2, participants read narratives and responded to recognition probes throughout the texts. Readers who were oriented to the spatial dimension were more likely to update their situation models at spatial changes; all readers tracked the character dimension. The results from both experiments indicated that attention to individual situational dimensions influences how readers segment and update their situation models. More broadly, the results provide evidence for a global situation model updating mechanism that serves to set up new models at important narrative changes.     

Mood effects on eyewitness memory: Affective influences on susceptibility to misinformation

Does mood influence the accuracy of eyewitness recollections, and people’s susceptibility to misleading information in particular? Based on recent affect-cognition theories and research on eyewitness memory, three experiments predicted and found that positive affect promoted, and negative affect inhibited the incorporation of misleading information into eyewitness memories. This effect was obtained for both positive and negative events (Experiment 1), and for recorded as well as real-life incidents (Experiment 2). Participants had no meta-cognitive awareness of these mood effects, and affect-control instructions were ineffective in preventing them (Experiment 3). The cognitive mechanisms responsible for mood effects on eyewitness memories are discussed, and the implications of these findings for everyday memories, forensic practice and for current affect/cognition theorizing are considered.     

The effects of social support on children's eyewitness testimony

Child witnesses often give only short accounts of witnessed events. Part of the reason for this failing centres on the stress present during an interview. The most obvious means of reducing stress in children, through the provision of social support, has typically been neglected in eyewitness research, presumably because of fears over children's excessive suggestibility. Social support is also believed to inhibit children during interviews. However, these fears appear to stem more from general suspicions about children's competencies rather than empirical findings. Studies are described which show that child witnesses express a strong desire for social support, and that support may be provided in a number of different ways, from peers as well as adults. It is argued that social support is one of the most unfairly neglected issues in eyewitness research, and the minimal evidence available suggests that allowing support may have a facilitative effect on task performance, including free-recall memory.     

The effects of prior knowledge on children's memory and suggestibility

In this study, 5- and 6-year-olds were read a story and asked to recall its details. Two independent factors-prestory knowledge and poststory suggestions-were crossed to examine the effects on children's story recall. The results indicated that prestory social knowledge about the story protagonist as well as academic knowledge relating to the content of the story influenced the accuracy of children's recall immediately after the story presentation. Following the suggestive interview, children reported interviewer-provided social and academic misinformation to a greater extent when the misinformation was consistent with their prior knowledge. In contrast, children were more likely to refute misinformation that contradicted their academic knowledge. These findings are discussed in terms of the mechanisms underlying the knowledge-memory and knowledge-suggestibility linkages.