Are multiple-trial experiments appropriate for eyewitness identification studies? Accuracy,choosing, and confidence across trials

Eyewitness identification experiments typically involve a single trial: A participant views an event and subsequently makes a lineup decision. As compared to this single-trial paradigm, multiple-trial designs are more efficient, but significantly reduce ecological validity and may affect the strategies that participants use to make lineup decisions. We examined the effects of a number of forensically relevant variables (i.e., memory strength, type of disguise, degree of disguise, and lineup type) on eyewitness accuracy, choosing, and confidence across 12 target-present and 12 target-absent lineup trials (N?=?349; 8,376 lineup decisions). The rates of correct rejections and choosing (across both target-present and target-absent lineups) did not vary across the 24 trials, as reflected by main effects or interactions with trial number. Trial number had a significant but trivial quadratic effect on correct identifications (OR?=?0.99) and interacted significantly, but again trivially, with disguise type (OR?=?1.00). Trial number did not significantly influence participants’ confidence in correct identifications, confidence in correct rejections, or confidence in target-absent selections. Thus, multiple-trial designs appear to have minimal effects on eyewitness accuracy, choosing, and confidence. Researchers should thus consider using multiple-trial designs for conducting eyewitness identification experiments.     

Biased lineup instructions and face identification from video images

Previous eyewitness memory research has shown that biased lineup instructions reduce identification accuracy, primarily by increasing false-positive identifications in target-absent lineups. Because some attempts at identification do not rely on a witness's memory of the perpetrator but instead involve matching photos to images on surveillance video, the authors investigated the effects of biased instructions on identification accuracy in a matching task. In Experiment 1, biased instructions did not affect the overall accuracy of participants who used video images as an identification aid, but nearly all correct decisions occurred with target-present photo spreads. Both biased and unbiased instructions resulted in high false-positive rates. In Experiment 2, which focused on video-photo matching accuracy with target-absent photo spreads, unbiased instructions led to more correct responses (i.e., fewer false positives). These findings suggest that investigators should not relax precautions against biased instructions when people attempt to match photos to an unfamiliar person recorded on video.     

The “other-accent” effect in voice recognition

The current paper examines an “other-accent” effect when recognising voices. English and Scottish listeners were tested with English and Scottish voices using a sequential lineup method. The results suggested greater accuracy for own-accent voices than for other-accent voices under both target-present and target-absent conditions. Moreover, self-rated confidence in response to target-absent lineups suggested greater confidence for own-accent voices than other-accent voices. As predicted, the other-accent effect noted here emerged more strongly for English listeners than for Scottish listeners, and these results are discussed within an expertise framework alongside both other-race effects in face recognition, and other-accent effects in word recognition. Given these results, caution is advised in the treatment of earwitness evidence when recognising a voice of another accent.     

Effects of postidentification feedback on eyewitness identification and nonidentification confidence

Two experiments investigated new dimensions of the effect of confirming feedback on eyewitness identification confidence using target-absent and target-present lineups and (previously unused) unbiased witness instructions (i.e., "offender not present" option highlighted). In Experiment 1, participants viewed a crime video and were later asked to try to identify the thief from an 8-person target-absent photo array. Feedback inflated witness confidence for both mistaken identifications and correct lineup rejections. With target-present lineups in Experiment 2, feedback inflated confidence for correct and mistaken identifications and lineup rejections. Although feedback had no influence on the confidence-accuracy correlation, it produced clear overconfidence. Confidence inflation varied with the confidence measure reference point (i.e., retrospective vs. current confidence) and identification response latency.     

The confidence-accuracy relationship in eyewitness identification: effects of lineup instructions, foil similarity, and target-absent base rates

Discriminating accurate from mistaken eyewitness identifications is a major issue facing criminal justice systems. This study examined whether eyewitness confidence assists such decisions under a variety of conditions using a confidence-accuracy (CA) calibration approach. Participants (N = 1,200) viewed a simulated crime and attempted 2 separate identifications from 8-person target-present or target-absent lineups. Confidence and accuracy were calibrated for choosers (but not nonchoosers) for both targets under all conditions. Lower overconfidence was associated with higher diagnosticity, lower target-absent base rates, and shorter identification latencies. Although researchers agree that courtroom expressions of confidence are uninformative, our findings indicate that confidence assessments obtained immediately after a positive identification can provide a useful guide for investigators about the likely accuracy of an identification.     

Identification accuracy of a single culprit in a multiple-perpetrator mock crime

IntroductionEyewitness identification research has mainly examined the identification accuracy of a single perpetrator but many actual crimes involve not one but several perpetrators.ObjectiveThe aim of the study was to examine the identification accuracy if only one lineup for one of the two perpetrators is presented in a multiple perpetrator crime.MethodThe sample consisted of 180 participants who saw a theft video followed by distraction tasks. One group of participants saw lineups for both of the perpetrators (one target present and one target-absent) whereas the other saw only a single lineup (either target-present or target-absent) for one of the two perpetrators.ResultsParticipants who saw a single lineup did not make more inaccurate identification decisions then participants who saw two lineups. Decision accuracy in the first lineup was not associated with the decision accuracy in the second lineup.ConclusionThe results are discussed in terms of the number of perpetrators and line-up presentation types.     

Change detection inflates confidence on a subsequent recognition task

A face viewed under good encoding conditions is more likely to be remembered than a face viewed under poor encoding conditions. In four experiments we investigated how encoding conditions affected confidence in recognising faces from line-ups. Participants performed a change detection task followed by a recognition task and then rated how confident they were in their recognition accuracy. In the first two experiments the same faces were repeated across trials. In the final two experiments novel faces were used on each trial. Target-present and target-absent line-ups were utilised. In each experiment participants had greater recognition confidence after change detection than after change blindness. The finding that change detection inflates confidence, even for inaccurate recognitions, indicates recognition certainty can be a product of perceived encoding conditions rather than authentic memory strength.     

Change detection inflates confidence on a subsequent recognition task

A face viewed under good encoding conditions is more likely to be remembered than a face viewed under poor encoding conditions. In four experiments we investigated how encoding conditions affected confidence in recognising faces from line-ups. Participants performed a change detection task followed by a recognition task and then rated how confident they were in their recognition accuracy. In the first two experiments the same faces were repeated across trials. In the final two experiments novel faces were used on each trial. Target-present and target-absent line-ups were utilised. In each experiment participants had greater recognition confidence after change detection than after change blindness. The finding that change detection inflates confidence, even for inaccurate recognitions, indicates recognition certainty can be a product of perceived encoding conditions rather than authentic memory strength.     

Improving the identification accuracy of senior witnesses: do prelineup questions and sequential testing help?

Eyewitness research has identified sequential lineup testing as a way of reducing false lineup choices while maintaining accurate identifications. The authors examined the usefulness of this procedure for reducing false choices in older adults. Young and senior witnesses viewed a crime video and were later presented with target present orabsent lineups in a simultaneous or sequential format. In addition, some participants received prelineup questions about their memory for a perpetrator's face and about their confidence in their ability to identify the culprit or to correctly reject the lineup. The sequential lineup reduced false choosing rates among young and older adults in target-absent conditions. In target-present conditions, sequential testing significantly reduced the correct identification rate in both age groups.     

Can a modified lineup procedure improve the usefulness of confidence?

In a face recognition, mini-lineup experiment we examined two aspects of the use of confidence about lineups. We modified the lineup procedure attempting to eliminate the difference in confidence–accuracy relationship between positive (old or identification) and negative (new or not present) decisions. In the modified procedure, participants: (1) selected the lineup member that best matched their memory of the target; (2) rated their confidence that the best match was indeed the target; and (3) indicated (yes/no) whether the best match was the target. Although the modified procedure produced higher accuracy than a standard simultaneous procedure, there was no evidence that it affected the confidence–accuracy relationship. Additionally, the modified procedure also allowed us to compare the extent to which confidence ratings versus binary recognition decisions better discriminated studied from unstudied faces. The results revealed a clear advantage for confidence, but indicated that binary responses were also a unique predictor.     

Participants' free‐hand drawings of a target face can influence recognition accuracy and the confidence–accuracy correlation

Two experiments were conducted to examine the effects of participants' free‐hand drawings on recognition accuracy and confidence for targets presented in a standard recognition paradigm and a lineup identification task. For both experiments, drawing a target influenced recognition accuracy and the confidence–accuracy correlation. In Experiment 1, the confidence–accuracy correlation was higher for participants completing a drawing than controls. Experiment 2 examined the drawings in relation to participants' decision to choose from the lineups. Once choosing was statistically controlled, the confidence–accuracy correlation for drawers was not higher than controls. These results suggest that the drawing influences the confidence–accuracy correlation by decreasing the likelighood of erroneously rejecting a target‐present lineup. Copyright © 2002 John Wiley & Sons, Ltd.     

Super-recognisers: Face recognition performance after variable delay intervals

Outstanding long-term face recognition of suspects is a hallmark of the exceptionally skilled police ‘super-recognisers’ (SRs). Yet, research investigating SR's memory for faces mainly employed brief retention intervals. Therefore, in Experiment 1, 597 participants (121 SRs) viewed 10 target videos and attempted identification of targets from 10 target-present line-ups after 1–56 days. In Experiment 2, 1,421 participants (301 SRs) viewed 20 target videos, and after a baseline of no delay to 28 days,—10 target-present and 10 target-absent line-ups, to assess correct line-up rejections. Overall, delay positively correlated with hits but not with correct rejections. Most, but not all SRs, made more correct identifications and correct rejections than controls at all retention intervals, demonstrating that many SRs possess enhanced long-term face memory. This research adds to the knowledge of SR's skillsets, and enhances the case for the selection of SRs to identity critical roles—particularly policing.     

Subjective experience guides betting decisions beyond accuracy: evidence from a metamemory illusion

The goal of this research was to test whether subjective memory experiences drive accuracy regulation decisions above and beyond objective memory indices. In four experiments (n?=?115) subjective recollection (i.e., reporting “Remember” in the Remember-Know task) was dissociated from memory accuracy by manipulating retrieval during a two-alternative forced-choice recognition task: in the Match condition the distracter was a novel exemplar of the target (e.g., a studied and an unstudied toaster) and in the Non-match condition the distracter was a novel exemplar of another studied but untested item (e.g., a studied toaster and an unstudied birdhouse). Participants were more accurate on Match trials, but reported subjective recollection more frequently on Non-match trials. Critically, participants also bet more often on Non-match trials to the detriment of their score (Experiment 1). This pattern persisted when participants were additionally required to retrieve details about items (Experiment 2) and when confidence assessments were collected (Experiment 3). Finally, participants bet more on Non-match trials even when subjective judgments were not elicited, suggesting that the decision process does not require reporting on subjective experience (Experiment 4). These results indicate that subjective memory experiences guide decision-making independent of objective accuracy and thus are critical to accuracy regulation.     

Attempts to Improve Children's Identifications From Sequential-Presentation Lineups

The effectiveness of practice and stringent lineup instructions in improving children's identifications from sequential-presentation lineups was investigated. Elementary school children ( N = 144) viewed a slide sequence of a crime followed by practice or control procedures. In the practice conditions, children either practiced themselves (self) or watched a videotape of a child practicing (modeled). Practice consisted of 2 target-absent lineups (unmixed) or a target-absent lineup and a target-present lineup (mixed) of female photos unrelated to the crime. The control conditions did not engage in identification practice. All witnesses were given stringent instructions for identifying the criminal from target-present or target-absent sequential-presentation lineups. Multiple responding was dramatically reduced. Practice affected gender differentially. Female children increased in correct identifications, whereas male children increased in false rejections. None of the practice procedures reduced foil identifications from target-absent lineups.     

The Effect of Mugshot Inspections on Eyewitness Identification Accuracy1

This study assessed the effect of commitment to an earlier mugshot identification on the ability to make a subsequent lineup identification. Shortly after viewing videotape of a staged assault some subjects rated a group of 18 photos for attractiveness, whereas other subjects attempted to identify the assailant publicly or privately in the same (target-absent) set of 18 “mugshot” photos. The remaining subjects had no intervening task. Two days later, all subjects attempted to identify the assailant from a six-person target-present photo lineup which contained their mugshot choice (if made) as well as the original assailant. Lineup identifications were significantly less accurate for subjects who had viewed the intervening mugshots (33% accuracy) than those who had only rated the intervening photos for attractiveness (64% accuracy) or had seen no intervening photos (69% accuracy). When viewing lineups, experimental subjects tended to remain committed to their earlier action of choosing or not choosing anyone from the mugshots. More witnesses who had publicly stated their mugshot choice reproduced their (incorrect) choice at the lineup (78%), than did those who made a private mugshot choice (45%), though this difference was not statistically reliable. Witnesses' confidence in their lineup decision was not significantly related to overall accuracy. Contrary to predictions from self-perception theory, confidence in one's decision decreased significantly as further identifications were attempted.     

Face and voice identifications in showups and lineups

Witnesses were asked to identify a young adult female target to whom they had spoken for 15 seconds five minutes earlier in a naturalistic field setting. Subjects were given a single facial photograph or a single tape-recorded voice of either the target or a highly similar foil, or a target-present or target-absent six-person photo lineup or six-person voice lineup. Identification of the target was superior in the six-person photo lineup than in the one-person photo lineup when choices were corrected for guessing. False identifications of the ‘innocent’ suspect did not differ in one-person and six-person photo lineups. However, the diagnosticity index indicated that witnesses were twice as likely to be more accurate than inaccurate in making a selection with the six-person photo lineup than in the one-person lineup. Performance was poor in both one-person and six-person voice lineups. With the exception of the target-absent one-person photo lineup, no significant correlations were found between confidence and performance.     

Using confidence ratings to identify a target among foils

Sauer, Brewer, and Weber (2008) advanced a novel procedure for testing eyewitness recognition memory. Rather than providing a single decision (i.e., identifying a lineup member or rejecting the lineup as a whole), participants rated their confidence that each lineup member was the culprit. Classification algorithms determined when patterns of confidence ratings indicated suspect guilt or innocence. Across varied test stimuli, confidence-based classifications equalled or out-performed single decisions. However, Sauer et al.’s classification criteria were designed to optimize performance for the data to which they were applied. If effective classification using confidence ratings requires such idiosyncratic criteria, the applied utility of the confidence procedure is nil. We re-analysed the data from Sauer et al.’s two identification experiments and demonstrated that confidence-based classification performance exceeding that of a traditional lineup task did not depend on uniquely developed classification criteria. Confidence-rating lineups offer a potentially promising alternative to procedures requiring single decisions from witnesses.     

Decision Strategies and the Confidence–Accuracy Relationship in Face Recognition

The decision strategy used to select a choice set from an array of alternative options is known to affect the composition of the final choice set. Specifically, individuals incorporate more answers into their choice set when it is created by eliminating implausible items than when the set is created through the inclusion of plausible options. This difference is accounted for in a decision framework that posits a general reluctance to change the status quo (i.e., actively include or exclude an item). We extended this work to investigate, not only the decisions themselves, but also metacognitive judgments (i.e., confidence in the accuracy of the choice set). In two face recognition experiments, we tested the impact of decision strategy (Experiment 1) and confidence judgment strategy (Experiment 2) on the confidence–accuracy relationship. In Experiment 1, participants completed two blocks of recognition trials, one under inclusion (marking previously seen faces) and one under elimination (marking previously unseen faces) instructions. We observed superior resolution (i.e., discrimination between correct and incorrect) for inclusion trials, but only when they were completed prior to use of the elimination strategy. In Experiment 2, all participants completed face recognition trials under inclusion instructions, but we manipulated the strategy used to assess confidence. Again, we observed a significant impact of strategy on confidence–accuracy resolution. Thus, we observed that both the strategy employed to reach a decision and that employed to assess confidence affected the confidence–accuracy relationship. We discuss theoretical and applied (particularly for eyewitness identification and multiple‐choice testing) implications. Copyright © 2012 John Wiley & Sons, Ltd.     

Building face composites can harm lineup identification performance

Face composite programs permit eyewitnesses to build likenesses of target faces by selecting facial features and combining them into an intact face. Research has shown that these composites are generally poor likenesses of the target face. Two experiments tested the proposition that this composite-building process could harm the builder's memory for the face. In Experiment 1 (n = 150), the authors used 50 different faces and found that the building of a composite reduced the chances that the person could later identify the original face from a lineup when compared with no composite control conditions or with yoked composite-exposure control conditions. In Experiment 2 (n = 200), the authors found that this effect generalized to a simulated-crime video, but mistaken identifications from target-absent lineups were not inflated by composite building.