Biomedical subjects

Gary L Wells

Publications and source records attributed to Gary L Wells.

13 recordsLinked to original sources

PubMed2007

Eyewitness lineups: is the appearance-change instruction a good idea?

The Department of Justice's Guide for lineups recommends warning eyewitnesses that the culprit's appearance might have changed since the time of the crime. This appearance-change instruction (ACI) has never been empirically tested. A video crime with four culprits was viewed by 289 participants who then attempted to identify the culprits from four 6-person arrays that either included or did not include the culprit. Participants either received the ACI or not and all were warned that the culprit might or might not be in the arrays. The culprits varied in how much their appearance changed from the video to their lineup arrays, but the ACI did not improve identification decisions for any of the lineups. Collapsed over the four culprits, the ACI increased false alarms and filler identifications but did not increase culprit identifications. The ACI reduced confidence and increased response latency. Two processes that could account for these results are discussed, namely a decision criterion shift and a general increase in ecphoric similarity.

Crime↗

PubMed2007

Catching the bad guy: morphing composite faces helps.

Composite faces built by eyewitnesses commonly are poor likenesses of the target face. When there are multiple witnesses, however, an opportunity exists to morph the composites. Morphs were rated as more similar to the target face than were the mean ratings of the individual composites. However, as hypothesized, the morph also came to resemble non-target faces more than the individual composites did (a prototype effect). This prototype effect was so strong that the morphs resembled non-targets more than the individual composites resembled the targets. In addition, morphing composites produced an attractiveness bias, which made the morphing of composites less effective for less attractive targets. Even when the prototype effect and the attractiveness bias were controlled for, however, a true morph-superiority effect continued to exist.

Crime↗

PubMed2006

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.

Adolescent↗

PubMed2005

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.

Adolescent↗

PubMed2005

Not the same old hindsight bias: outcome information distorts a broad range of retrospective judgments.

The hindsight bias (e.g., Fischhoff, 1975) illustrates that outcome information can make people believe that they would have (or did) predict an outcome that they would not (or did not) actually predict. In two experiments, participants (N = 226) made a prediction immediately before receiving outcome information. Therefore, participants could not distort or misremember their predictions to make them align with the outcome information. In both experiments, participants distorted their reports of how certain they recalled having been in their prediction, how good of a basis they had for making the prediction, how long they took to make the prediction, and so forth. Experiment 2 showed that these effects were diminished when participants engaged in private thought about the upcoming questions prior to receiving outcome information, suggesting that the effect is not due to impression management concerns.

Adult↗

PubMed2004

What makes a good alibi? A proposed taxonomy.

A taxonomy of alibis is proposed involving two forms of supporting proof: physical evidence and person evidence. Levels of physical evidence and person evidence were combined to create 12 cells in the taxonomy. Participants (n = 252), who were asked to assume the role of detectives, evaluated alibis representing these 12 cells. The believability of the alibis generally followed the taxonomy's predicted pattern, but physical evidence, when present, tended to overwhelm the person evidence more than had been expected. In addition, alibi evaluators seemed to not consider the possibility that a stranger who corroborated an alibi might be mistaken about the identity of the person. Trait inferences regarding the alibi providers tended to follow the believability data, even when the traits themselves were not relevant to believability of the alibi. We call for the development of a literature on the psychology of alibis, recommend the taxonomy as a framework, and suggest several avenues of inquiry.

Classification↗

PubMed2004

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.

Adolescent↗

PubMed2004

Eyewitness identification accuracy and response latency: the unruly 10-12-second rule.

Data are reported from 3,213 research eyewitnesses confirming that accurate eyewitness identifications from lineups are made faster than are inaccurate identifications. However, consistent with predictions from the recognition and search literatures, the authors did not find support for the "10-12-s rule" in which lineup identifications faster than 10-12 s maximally discriminate between accurate and inaccurate identifications (D. Dunning & S. Perretta, 2002). Instead, the time frame that proved most discriminating was highly variable across experiments, ranging from 5 s to 29 s, and the maximally discriminating time was often unimpressive in its ability to sort accurate from inaccurate identifications. The authors suggest several factors that are likely to moderate the 10-12-s rule.

Crime↗

PubMed2003

Murder, extramarital affairs, and the issue of probative value.

A paper previously published in Law and Human Behavior by D. Davis and W. C. Follette (2002) argued that certain "profiling" characteristics commonly admitted into court have little or no probative value. They argued that this is especially likely to be true when the characteristic used as evidence (e.g., having an extramarital affair) is rather common in the population whereas the act in question (e.g., a man murdering his wife) is rare. Their analysis has prompted a strong response by Friedman and Park and by Kaye and Koehler with a rejoinder by Davis and Follette (all three follow this paper in this issue of Law and Human Behavior). This paper describes some of the nature of this controversy.

Decision Making↗

PubMed2003

Distorted retrospective eyewitness reports as functions of feedback and delay.

Participant-witnesses viewed a crime video and attempted to identify the culprit from a culprit-absent lineup. The 253 mistaken-identification eyewitnesses were randomly given confirming, disconfirming, or no feedback regarding their identifications. Feedback was immediate or delayed 48 hr, and measures were immediate or delayed 48 hr. Confirming, but not disconfirming, feedback led to distortions of eyewitnesses' recalled confidence, amount of attention paid during witnessing, goodness of view, ability to make out facial details, length of time to identification, and other measures related to the witnessing experience. Unexpectedly, neither delaying the measures nor delaying feedback for 48 hr moderated these effects. The results underscore the need for double-blind lineups and neutral assessments of eyewitnesses' certainty and other judgments prior to feedback.

Attention↗

PubMed2002

Eyewitness testimony.

The criminal justice system relies heavily on eyewitness identification for investigating and prosecuting crimes. Psychology has built the only scientific literature on eyewitness identification and has warned the justice system of problems with eyewitness identification evidence. Recent DNA exoneration cases have corroborated the warnings of eyewitness identification researchers by showing that mistaken eyewitness identification was the largest single factor contributing to the conviction of these innocent people. We review major developments in the experimental literature concerning the way that various factors relate to the accuracy of eyewitness identification. These factors include characteristics of the witness, characteristics of the witnessed event, characteristics of testimony, lineup content, lineup instructions, and methods of testing. Problems with the literature are noted with respect to both the relative paucity of theory and the scarcity of base-rate information from actual cases.

Criminal Law↗

PubMed2002

The damaging effect of confirming feedback on the relation between eyewitness certainty and identification accuracy.

The authors investigated eyewitnesses' retrospective certainty (see G. L. Wells & A. L. Bradfield, 1999). The authors hypothesized that extemal influence from the lineup administrator would damage the certainty-accuracy relation by inflating the retrospective certainty of inaccurate eyewitnesses more than that of accurate eyewitnesses (N = 245). Two variables were manipulated: eyewitness accuracy (through the presence or absence of the culprit in the lineup) and feedback (confirming vs. control). Confirming feedback inflated retrospective certainty more for inaccurate eyewitnesses than for accurate eyewitnesses, significantly reducing the certainty-accuracy relation (from r = .58 in the control condition to r = .37 in the confirming feedback condition). Double-blind testing is recommended for lineups to prevent these external influences on eyewitnesses.

Adolescent↗

PubMed2002

Eyewitness identification: information gain from incriminating and exonerating behaviors.

An information-gain approach to the analysis and interpretation of eyewitness identification data is described. The information-gain analysis is grounded in Bayesian statistics, permitting the important role of prior probabilities to be explored. This approach also forces a more complete treatment of the data and reveals important patterns that have escaped previous attention in the eyewitness identification literature. Particularly important is the ability of information-gain analyses to make salient the exonerating value of eyewitness behaviors rather than just their incriminating value. Analyses of sample data sets show how the exonerating value of filler identifications and "not there" responses can actually exceed the incriminating value of identifications of the suspect at certain points in the distribution of prior probabilities.

Attention↗