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.     

Post‐identification feedback effects: Investigators and evaluators

We investigated the effects of post‐identification feedback and viewing conditions on beliefs and interviewing tactics of participant‐investigators, crime reports of participant‐witnesses and participant‐evaluators' credibility judgments of the witnesses. Study 1 participants assumed the roles of witness and investigator (N = 167 pairs). Witnesses' view of a simulated crime video was manipulated by distance from viewing monitor: 2 or 9 ft. Participants made a line‐up identification and received either positive feedback or no feedback. Significant effects for witnesses and investigators were associated with viewing condition and post‐identification feedback. Interviews between investigator‐witness pairs were videotaped. Investigators asked more positive, leading questions when they were led to believe that the witness had identified the suspect. In Study 2 evaluators (N = 302) viewed the witness‐investigator interviews. Viewing condition had no effect on judgments of witness credibility but positive post‐identification feedback led evaluators to judge witnesses as more credible than witnesses who received no feedback. Copyright © 2010 John Wiley & Sons, Ltd.     

Protecting Against Misleading Post‐event Information with a Self‐Administered Interview

Two studies investigated whether an early recall opportunity, in the form of a self‐administered interview (SAI), reduced forgetting and protected against the negative consequences of post‐event misinformation. In both studies, participants viewed a simulated crime on DVD after which half immediately recorded their statement by using the SAI, whereas control participants did not have an immediate recall opportunity. Following a delay, participants were presented with misinformation encountered either in a misleading news report (Study 1) or in the form of misleading cued‐recall questions (Study 2). Results showed that participants who had completed a SAI after witnessing an event were significantly less prone to forgetting and significantly more resistant to the negative consequences of misinformation. The SAI was able to protect both the quantity and quality of information about a previously witnessed event. Applied implications are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Peer discussion affects children's memory reports

This study explored the memory conformity effect in children. Younger (6–7 years; n = 60) and older (11–12 years; n = 62) children watched a video individually (individual witness condition) or in dyads (co‐witness condition). The dyads believed that they were viewing the same video as the other member of the pair while in fact the saw different versions. Next, children in the individual witness condition answered questions, whereas children in the co‐witness condition discussed the event on the video with each other. Finally, all children completed an individual free and cued recall task. In the co‐witness condition, more than 60% of the children recalled at least one detail from the alternative video, whereas over 23% of the children in the individual witness condition reported such a detail. Moreover, in free recall—but not in cued recall—the memory conformity effect was stronger for older than for younger children. Copyright © 2007 John Wiley & Sons, Ltd.     

The effect of cross‐examination on the accuracy of adult eyewitness testimony

Cross‐examination permits styles of questioning that increase eyewitness error (e.g. leading questions). Previous research has shown that under cross‐examination children change many of their initially accurate answers. An experiment is reported in which the effect of cross‐examination on accuracy of adult eyewitness testimony was investigated. Twenty‐two student witnesses watched a video of a staged theft, either in pairs, or individually. Paired witnesses discussed the video with their co‐witnesses, but did not know they had seen slightly different versions. Participants in the co‐witness condition demonstrated memory conformity and recalled less accurately than witnesses in the control condition. After approximately 4 weeks all participants were cross‐examined by a trainee barrister. Following cross‐examination there was no difference in accuracy between the two experimental groups. Witnesses in both conditions made many changes to their previous reports by altering both initially correct and incorrect answers. The results demonstrate negative effects of cross‐examination on the accuracy of adult eyewitness testimony. Copyright © 2010 John Wiley & Sons, Ltd.     

Post‐event information presented in a question form eliminates the misinformation effect

This study investigated the influences of sentence surface forms on the misinformation effect. After viewing a film clip, participants received a post‐event narrative describing the events in the film. Critical sentences in the post‐event narrative, presented in either a statement or a question form, contained misinformation instead of questions with embedded false presuppositions; thus participants did not have to answer questions about the original event. During the final cued‐recall test, participants were informed that any relevant information presented in the post‐event narrative was not in the original event and that they should not report it. Consistent with previous findings, Experiment 1 demonstrated that post‐event information presented as an affirmative statement produced the misinformation effect. More importantly, post‐event information presented in a question form, regardless of whether it contained a misleading or studied item, increased the recall of correct information and reduced false recall. Experiment 2 replicated the main finding and ruled out an alternative explanation based on the salience of misleading items. Post‐event information presented in a question form created a condition similar to that which produces the testing effect.     

Co‐Witness Confidence,Conformity, and Eyewitness Memory: An Examination of Normative and Informational Social Influences

We explored conformity and co‐witness confidence in eyewitness memory. Confederates provided misleading information and confidence ratings during a cued recall test, and participants publicly provided answers to this test in turn. Participants performed memory tests with a confederate, then completed individual memory tests. Results indicated that confederates who answered questions prior to participants impacted their public and private memory reports for accurate information but only impacted public reports for misleading information. Participants' confidence in their performance in the presence of a confederate mirrored the confederate's confidence levels, suggesting a confidence conformity effect. Results are explained in terms of differential effects of informational and normative influence for accuracy and confidence in co‐witness memory reports. Copyright © 2012 John Wiley & Sons, Ltd.     

The effects of anxious mood induction on suggestibility to misleading post‐event information

Little research has been carried out into the effects of anxious mood at the time of either the encoding of misleading post‐event information or the time of its possible retrieval, on subsequent suggestibility. Participants comprised 160 first‐year undergraduates. Using a standard suggestibility paradigm, half of all participants were exposed to misleading information while half were non‐misinformed controls. In addition there were four state anxiety conditions, dependent on the timing of the anxious mood induction: at the time of encoding misleading information; at retrieval only; at both encoding and retrieval; or at neither encoding nor retrieval (controls). Results showed memory accuracy for non‐suggestible items was unaffected by the anxious mood induction. With respect to suggestibility, there was a strong effect of misleading information. In addition, within the misinformed group, all three groups who experienced the anxious mood induction were significantly less suggestible than controls. These findings are discussed both in terms of theories of anxiety and cognition and the applied implications for the increasing use by the police of video‐recorded witness interviews. Copyright © 2004 John Wiley & Sons, Ltd.     

Memory conformity: can eyewitnesses influence each other's memories for an event?

The current study investigated memory conformity effects between individuals who witness and then discuss a criminal event, employing a novel procedure whereby each member of a dyad watches a different video of the same event. Each video contained unique items that were thus seen only by one witness. Dyads in one condition were encouraged to discuss the event before each witness (individually) performed a recall test, while in a control condition dyads were not allowed to discuss the event prior to recall. A significant proportion (71%) of witnesses who had discussed the event went on to mistakenly recall items acquired during the discussion. There were no age‐related differences in susceptibility to these memory conformity effects in younger (18–30 years) as compared to older (60–80 years) participants. Possible social and cognitive mechanisms underlying the distortions of memory due to conformity are discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

Susceptibility to postidentification feedback is affected by source credibility

How much a person is affected by postidentification feedback is dependent on the credibility of the person giving the feedback. Seven hundred and ninety participants across three experiments viewed a crime video, made judgments from a line‐up, were provided with co‐witness and/or outcome feedback (from police officers [high credibility] or children [low credibility]), and answered testimony‐relevant questions (e.g. How good a view did you get of the person in the video?). The aim was to find out how high versus low credibility co‐witness feedback affects a witness' retrospective judgments (Experiment 1) as well as estimations of these co‐witnesses' judgments (Experiment 2). Experiment 1 showed that the feedback effect was only observed when the co‐witness responses were attributed to a high credibility source. Experiment 2 showed that high credibility co‐witnesses were estimated to score higher on the testimony‐relevant questions as compared to low credibility co‐witnesses. Experiment 3 showed that outcome feedback (e.g. ‘you identified the suspect’) produces stronger effects on testimony‐relevant questions than co‐witness feedback. The implications of these findings are that when postidentification feedback is present, it is important to determine the source of this feedback. Copyright © 2008 John Wiley & Sons, Ltd.     

A comfortable witness is a good witness: rapport‐building and susceptibility to misinformation in an investigative mock‐crime interview

Major investigative interviewing protocols such as the Cognitive Interview recommend that investigators build rapport with cooperative adult witnesses at the beginning of a police interview. Although research substantiates the benefits of rapport‐building on the accuracy of child witness reports, few studies have examined whether similar benefits apply to adult witnesses. The present study investigated whether verbal rapport‐building techniques increase adult witness report accuracy and decrease their susceptibility to post‐event misinformation. One‐hundred eleven college adults viewed a videotaped mock‐crime, received post‐event misinformation (or correct information) about the crime, and were subsequently interviewed by a research assistant who built rapport (or did not build rapport) before recalling the mock‐crime. Results indicated that rapport‐building increased the quality of witness recall by decreasing the percentage of inaccurate and misinformation reported, particularly in response to open‐ended questions. We discuss implications and recommendations for law enforcement. Copyright © 2011 John Wiley & Sons, Ltd.     

The Self‐Administered Witness Interview Tool (SAW‐IT): Enhancing witness recall of workplace incidents

Given the often crucial role of witness evidence in occupational health and safety investigation, statements should be obtained as soon as possible after an incident using best practice methods. The present research systematically tested the efficacy of a novel Self‐Administered Witness Interview Tool (SAW‐IT), an adapted version of the Self‐Administered Interview designed to elicit comprehensive information from witnesses to industrial events. The present study also examined the effect of schematic processing on witness recall. Results indicate that the SAW‐IT elicited significantly more correct details, as well as more precise information than a traditional incident report form. Contextual information about a worker's safety history biased the reports of participant witnesses, confirming that witnesses should be shielded from extraneous post‐event information prior to reporting. Importantly, these results demonstrate that the SAW‐IT can enhance the quality of witness reports.     

Co‐witness feedback in line‐ups

The aim of the current study was to establish whether feedback from a co‐witness concerning their choice of suspect could influence an individual witness' certainty and other testimony‐relevant judgements. Eighty‐two university students and members of the general public viewed a film of a staged mugging in pairs and then made an identification of who they thought was the suspect from a culprit‐absent line‐up (i.e. identification parade). The participants were then required to tell their partner whom they had identified and to fill out a questionnaire with testimony‐relevant questions (e.g. How good a view did you get of the person in the line‐up?). When the pairs of participants agreed on their choice of suspect, their scores on the testimony‐relevant questions tended to be higher than when the pairs did not agree. This shows that co‐witnesses can influence each others' memory reports when giving each other feedback after the identification process. The implications of these findings are discussed. Copyright © 2006 John Wiley & Sons, Ltd.     

Memory conformity: Disentangling the steps toward influence during a discussion

When two people see the same event and discuss it, one person’s memory report can influence what the other person subsequently claims to remember. We refer to this asmemory conformity. In the present article, two factors underlying the memory conformity effect are investigated. First, are there any characteristics of the dialogue that predict memory conformity? Second, is memory conformity differentially affected when information is encountered that omits, adds to, or contradicts originally encoded items? Participants were tested in pairs. The two members of each pair encoded slightly different versions of complex scenes and discussed them prior to an individual free recall test. The discussions were audiotaped, transcribed, and analyzed. Our most striking finding was that the witness initiating the discussion was most likely to influence the other witness’s memory report. Furthermore, witnesses were most likely to be influenced when an additional (previously unseen) item of information was encountered in the discussion.     

Reevaluating the potency of the memory conformity effect

Witnesses sometimes report event details that are acquired solely from another witness. We reevaluated the potency of this memory conformity effect. After viewing a crime video, some participants learned about nonwitnessed details via discussion (dyad group), reading another participant’s report (read group), or watching another version of the video (both-video group). In Experiment 1, these participants often reported nonwitnessed details, but on a source-judgment test most details were attributed primarily to the actual source rather than to the video. In addition, the dyad group was not more likely than the read or both-video groups to report nonwitnessed details. Participants in Experiment 2 were explicitly discouraged from providing details that were remembered from the secondary source only. These postwarning instructions substantially reduced the memory conformity effect, and a dyad group was not more likely than a read group to report nonwitnessed details. Encouraging source monitoring at test can reduce the negative consequences of co-witness collaboration.     

Dividing attention during a witnessed event increases eyewitness suggestibility

Real‐life witnesses often encounter complex situations that may prevent them from devoting their full attention to encoding forensically‐relevant information about the event. Although prior research has demonstrated that divided attention can impair aspects of event memory, the current study examined the effect of attention during encoding of the event on participants' memory for the source of post‐event misleading information. Participants first viewed a slide sequence depicting a theft under full or divided attention conditions. Subsequently, they answered questions about the event that included misleading information, and finally received a source test. Results revealed that Divided Attention participants showed poorer memory for event items and were more likely to misattribute post‐event misinformation to the event than were Full Attention participants. The findings suggest that typical laboratory conditions (which allow full deployment of attentional resources during encoding) may underestimate the suggestibility of witnesses. Copyright © 2006 John Wiley & Sons, Ltd.     

Effects of communication with non‐witnesses on eyewitnesses' recall correctness and meta‐cognitive realism

In forensic contexts it is common that witnesses retell and discuss the experienced event many times. It is of forensic importance to understand how this influences memory and meta‐memory. Eighty‐nine participants viewed a short film and were assigned to one of four conditions: (1) Laboratory discussion (five discussions of the event with a confederate), (2) Family discussion (five discussions of the event with a family member), (3) Retell (five retellings of the event) and (4) Control. Three weeks later participants gave an open free recall, and then 3 days later confidence judged the recalled information. The results showed significant differences between the four conditions on number of correct items, incorrect items, accuracy, confidence and calibration. The results suggest that discussion of an experienced event may reduce some of the beneficial memory and meta‐memory effects caused by mere retelling, but may have no great negative effects compared to a control condition. Copyright © 2010 John Wiley & Sons, Ltd.