Influence of confidence inflation and explanations for changes in confidence on evaluations of eyewitness identification accuracy

Guidelines for conducting police line‐ups typically recommend immediate assessment of eyewitness confidence following identification. This confidence level can presumably be used to estimate accuracy even in the presence of subsequently inflated confidence. In this experiment, we examined students' perceptions of immediate and inflated confidence and whether their reliance on confidence varies as a function of the explanations given by the eyewitness for her inflated confidence. Each of 126 university students viewed one of five versions of a videotaped officer–eyewitness interaction depicting an eyewitness identification and follow‐up interview in which the eyewitness gave a (1) high or (2) moderate level of confidence or inflated her confidence and gave a (3) confidence epiphany, (4) memory contamination, or (5) no explanation for the inflation. The memory contamination and confidence epiphany explanations led to lower ratings of identification accuracy as compared to the high‐confidence control condition, supporting the immediate confidence recommendation but in some ways contradicting previous research on this issue. The results suggest the need for further research to understand the conditions under which confidence inflation influences juror evaluations of eyewitness identification.     

Inconsistencies across repeated eyewitness interviews: supportive negative feedback can make witnesses change their memory reports

Past work shows that direct negative feedback and suggestive questioning can lead eyewitnesses to change their memory reports. Applying Gudjonsson’s [2003. The psychology of interrogations and confessions: A handbook. West Sussex: Wiley] model of interrogative suggestibility to interviews with witnesses, the present two experiments examined how indirect negative feedback delivered in a supportive manner from an interviewer can make witnesses change what they report they remember experiencing. After viewing a video of a crime, participants were interviewed twice, with either supportive negative feedback (i.e. with the interviewer sympathetically suggesting why many people’s memory may be inaccurate) or neutral feedback between the two rounds of questions. Results showed that people given supportive negative feedback changed significantly more of their responses than those given neutral feedback. Lower confidence ratings were associated with greater response change, but overall, despite having changed more responses, people given supportive negative feedback did not have reduced confidence or perceived accuracy. Type of feedback did not impact accuracy, and accuracy was not systematically related to confidence or perceived accuracy. Given the role that eyewitness reports play in the criminal justice system, better understanding factors that impact consistency and reliability is vital.     

The impact of general versus specific expert testimonyand eyewitness confidence upon mock juror judgment

Subjects (n=128) initially viewed an eyewitness of high or low confidence. Subsequently, participants viewed a psychologist who gave either espert testimony on the unreliability of eyewitness identification, specific expert testimony, or no expert (control) testimony. Subjects viewing expert testimony believed the eyewitness identified the gunman significantly less often, gave the defendant lower guilt ratings, estimated a lower general percentage of correct identifications under similar circumstances, estimated a lower percentage of general accurate eyewitness testimony, and gave significantly lower ratings to the belief that one can generally tell from eyewitness confidence whether an eyewitness is accurate than subjects in control conditions. Significant differences were also obtained between general and specific expert testimony. Participants viewing specific expert testimony estimated lower general percentages of correct identifications under the circumstances of the crime and reported relying more upon the psychologist's testimony than subjects viewing general expert testimony. Additionally, subjects viewing general expert testimony had significantly less confidence in their gunman vs. innocent person decision than subjects in specific testimony or control conditions. Subjects who viewed the high confidence eyewitness decided that the eyewitness correctly identified the gunman more often, gave the defendant higher guilt ratings, and estimated the general percentage of accurate eyewitness testimony to be significantly higher than jurors in low eyewitness confidence groups. The finding that jurors may continue to rely on eyewitness confidence to gauge the accuracy of the witness even after viewing expert testimony is discussed.     

When Does Evidence of Eyewitness Confidence Inflation Affect Judgments in a Criminal Trial?

Two studies investigated perceptions of eyewitness confidence inflation: increases in a witness's confidence between the time of the identification and the trial. Experiment 1 (N = 90) demonstrated that, for White participants, assessments of the strength of the defense case, the eyewitness's view, and participants' confidence in the eyewitness's accuracy were more favorable to the defense when there was evidence that the eyewitness's confidence increased over time (mere inflation condition), compared with a control condition. In addition, assessments of the defendant's guilt and the eyewitness's accuracy were more favorable to the defense when the eyewitness was aggressively challenged about the change in her confidence report (inflation + challenge). Experiment 2 (N = 360) demonstrated that, for Hispanic participants, sensitivity to confidence inflation did not interact with manipulations of the eyewitness's or defendant's race (White vs. Hispanic). In addition, the confidence inflation effect did not replicate with the Hispanic participants. Results are interpreted in terms of the ingroup bias in legal judgments and directions for future research.     

证人的目击面孔心理重建及认知检测

提取目击证人对犯罪嫌疑人的面孔记忆是一项困难的工作,由于证人在识记面孔时有多种影响因素,在提取和再认记忆时又会有各种认知因素的影响,导致面孔心理重建的失真。因此,从认知心理学和实验心理学的角度入手,分析影响心理重建的因素,并用最佳的手段提取记忆,可以使面孔重建的可靠性最大化。认知相关电位在记忆检测领域的日臻完善,使目击证人的再认正确与否有了可靠的参照,从记忆反应的脑电图形分析,可以有效判断证人对列队辨认中的面孔是否存有记忆。     

Juror decision making in eyewitness identification cases

The lay-person's knowledge of the factors that influence eyewitness memory was examined by evaluating the manner in which mock jurors integrated eyewitness evidence to draw inferences about defendant culpability and the likelihood that an identification was correct. Three hundred and twenty-one undergraduates viewed a videotaped trial within which ten witness and identification factors were manipulated between trials. Manipulation checks showed that subjects demonstrated superior memory for the evidence and the manipulated variables had their intended impact on appropriate rating scales. However, only one variable, witness confidence, had reliable effects on subjects' perceptions of culpability, on the perceived likelihood that the identification was correct, and on several other relevant dependent variables. Eight variables that have been shown to affect identification accuracy in the empirical literature had trivial effects on mock jurors' inferences. It was concluded that lay-people are insensitive to the factors that influence eyewitness memory.     

Eyewitness accuracy and confidence

In deciding the trustworthiness of eyewitness testimony, the U.S. judiciary employs as one of five criteria the witness' level of confidence demonstrated at the confrontation. A very recent laboratory study has shown that juror perceptions of witness confidence account for 50% of the variance in juror judgments as to witness accuracy. This strong faith in the adequacy of certainty as a predictor of accuracy is not at all supported by the present review of 43 separate assessments of the accuracy/confidence relation in eye- and earwitnesses. Statistical support is provided for the notion that the predictability of accuracy from overtly expressed confidence varies directly with the degree of optimality of information-processing conditions during encoding of the witnessed event, memory storage, and testing of the witness' memory. Low optimal conditions, those mitigating against the likelihood of highly reliable testimony, typically result in a zero correlation of confidence and accuracy. Using the arbitrary criterion of 70% or greater accuracy to define high optimal conditions, seven forensically relevant laboratory studies are identified, with six of them exhibiting significant positive correlations of confidence and accuracy. It is concluded, however, that no really clear criteria currently exist for distinguishing post hoc high from low optimal witnessing conditions in any particular real-life situation. Hence the judiciary should cease their reliance on witness confidence as an index of witness accuracy.     

Effects of expert psychological advice on human performance in judging the validity of eyewitness testimony

A review is made of recent experimental research regarding how well human observers can judge the accuracy of eyewitness testimony. It is concluded that people: (a) may be overwilling to believe in the accuracy of eyewitnesses' memory; (b) rely too heavily on the confidence of eyewitnesses in judging the validity of testimony; (c) fail to adequately account for witnessing conditions across crimes; and (d) cannot discriminate between accurate and inaccurate witnesses within crimes. New data are reported from an experiment designed to test the effects that expert psychological advice has on subject-jurors' performance with regard to these four deficiencies. The results showed that expert advice served to eliminate the overbelief bias and greatly reduced subject-jurors' reliance on the confidence of the witnesses. Expert, advice did not improve the extent to which subject-jurors took account of the witnessing conditions across crimes nor their ability to discriminate between accurate and inaccurate witnesses within crimes.     

Some conditions maximizing eyewitness accuracy: A learning/memory analogy

Jurors continue to rely heavily on eyewitness testimony despite numerous demonstrations that it is often inaccurate. As part of the effort to provide jurors with good estimates of the accuracy of any specific testimony, a study was designed to test the proposal that eyewitness accuracy is governed by the same variables and in the same way as is retention of much simpler material in classical learning and memory paradigms. Prior exposure to the criminal (trials), arousal value of the incident (drive), and delay between prior exposure and incident, and between incident and test (inner-trial intervals) all affected eyewitness accuracy in the expected manner. Correct recognitions of the criminal in a line-up ranged from 14 percent to 86 percent, depending on the particular conditions under which the incident was observed.     

Spontaneous hypnosis in the forensic context

"Hypnosis" denotes either specific phenomena (altered volition, perception, cognition, and recall) or interpersonal transactions that often elicit them. Basic research leads to paradox: hypnosis is validated, and shown to be dissociative in essence, at the same time that neither its phenomena nor transactions can be separated from those of everyday living without logical absurdity. This paradox can be resolved by assuming that consciousness and volition are complex, occurring simultaneously at many levels in the same waking individual. Hypnotic-like phenomena and transactions occur spontaneously, in either covert or overt forms. The former are pervasive, whereas the latter are often associated with psychological trauma. Forensic implications are twofold: for criminal responsibility, and the reliability of eyewitness testimony. Hypnotic-like states and transactions are rarely affirmed as an insanity defense because at some level these subjects are aware of what they are doing and why. Diminished capacity and mitigation of sentence are more appropriate defense strategies. Several conflicted traditions of case law have evolved to protect eyewitness testimony from hypnotic-like distortions in cognition, perception, and memory that can occur either during or outside of formal hypnotic procedures. These include the admissibility of posthypnotic testimony, due process safeguards at eyewitness identification procedures, and the admissibility of expert testimony on the findings of eyewitness research. These areas are inseparable from one another and demand a systematic coordinated approach.     

Judging guilt and accuracy: highly confident eyewitnesses are discounted when they provide featural justifications

Jurors are heavily swayed by confident eyewitnesses. Are they also influenced by how eyewitnesses justify their level of confidence? Here we document a counter-intuitive effect: when eyewitnesses identified a suspect from a lineup with absolute certainty (‘I am completely confident’) and justified their confidence by referring to a visible feature of the accused (‘I remember his nose’), participants judged the suspect as less likely to be guilty than when eyewitnesses identified a suspect with absolute certainty but offered an unobservable justification (‘I would never forget him’) or no justification at all. Moreover, people perceive an eyewitness’s identification as nearly 25% less accurate when the eyewitness has provided a featural justification than an unobservable justification or simply no justification. Even when an eyewitness’s level of confidence is clear because s/he has expressed it numerically (e.g. ‘I am 100% certain’) participants perceive eyewitnesses as not credible (i.e. inaccurate) when the eyewitness has provided a featural justification. However, the effect of featural justifications – relative to a confidence statement only – is maximal when there is an accompanying lineup of faces, moderate when there is a single face and minimal when there is no face at all. The results support our Perceived-Diagnosticity account.     

Extra Effort During Memory Retrieval May Be Associated with Increases in Eyewitness Confidence

When testifying in court, witnesses are motivated to try as hard as possible to give an accurate account. This study tested the proposition that extra effort by eyewitnesses during a memory test can lead to higher confidence ratings without any accompanying changes in accuracy. Participant-witnesses answered multiple-choice questions about a classroom visitor who had spoken 5 days earlier. In the high-motivation condition participants could earn prizes based on their memory test performance; in the low-motivation condition there were no special incentives. Although the motivation manipulation did not affect mean witness confidence, the confidence–accuracy and effort–accuracy correlations were substantially smaller in the high-motivation condition than in the low-motivation condition. Furthermore, the confidence ratings for those participants who reported expending high levels of effort in both motivation conditions were significantly higher than the confidence ratings for the low-effort participants, despite the fact that response accuracy did not differ as a function of reported effort. These findings have important implications for understanding how pressures to perform well in the courtroom can affect eyewitness confidence.     

Eyewitness susceptibility to co-witness misinformation is influenced by co-witness confidence and own self-confidence

If an eyewitness is exposed to a co-witness statement that incorrectly blames an innocent bystander for a crime, the eyewitness can be influenced by this statement and also blame the innocent bystander for the crime. This effect is known as blame conformity. In two studies, we examined whether or not this effect is influenced by the degree of confidence a co-witness expresses in her incorrect statement (Study 1) and an eyewitness’s own level of self-confidence (Study 2). Participant eyewitnesses first watched a crime video featuring a perpetrator and an innocent bystander, then read a co-witness statement about the crime that either correctly blamed the perpetrator, incorrectly blamed the innocent bystander, or blamed nobody (a control condition). They were then asked who committed the crime. In Study 1, participants who read an incorrect statement were at increased risk of engaging in blame conformity when the co-witness expressed a high level of confidence, compared to a low level of confidence, in the accuracy of her statement. In Study 2, participants who were lowest in self-confidence were at increased risk of engaging in blame conformity. The theoretical underpinnings of these effects are considered.     

When is an intervening line‐up most likely to affect eyewitness identification accuracy?

Purpose. Intervening line‐ups affect identification accuracy in subsequent line‐ups. We conducted 3 experiments to investigate the conditions under which viewing multiple line‐ups is more likely to affect eyewitness identification accuracy. Method. In each of the 3 experiments, a forensically relevant factor known to affect the accuracy of face recognition memory was manipulated to assess how the factor impacted the suggestive influence of an intervening line‐up on eyewitness identification accuracy in a subsequent test line‐up. These factors were (a) in Experiment 1, same‐race versus cross race target faces, (b) in Experiment 2, whether the intervening line‐up occurred on the day of the presentation phase (close to presentation) or 1 month later on the day of the subsequent test line‐up (far from presentation), and (c) in Experiment 3, whether the target face was presented for 10 seconds or 60 seconds. Results. In each experiment, factors associated with poorer memory for the target face led to a greater suggestive influence of the intervening line‐up on identification accuracy in the subsequent line‐up, evidenced by lower hit rates and higher false‐alarm rates. Conclusions. These findings suggest that the problem of decreased identification accuracy following the viewing of an intervening photograph is especially of concern when memory for the perpetrator is likely to be poor. Implications of these findings for interpreting line‐up results in the courtroom are discussed.     

Validity in judgments of high‐ and low‐accurate witnesses of own and other ethnic groups

Purpose. Research has shown that people often have difficulties estimating eyewitness accuracy correctly. In most previous studies examining validity in credibility judgments, participants have assessed the accuracy of witnesses who have been homogeneous in their memory performance. This study investigated validity in judgments of witnesses who varied widely in memory. A further purpose was to examine whether judgmental validity was moderated by the witnesses' ethnic in‐group/out‐group status. Methods. Participants (N = 120) rated the reliability of videotaped testimonies of high‐ and low‐accurate in‐group (Swedish, N = 4) and out‐group (immigrants, N = 4) witnesses who were genuinely trying to recall a criminal event. Results. Participants assigned more reliability to high‐ than to low‐accurate in‐group witnesses, while out‐group witnesses received low reliability ratings regardless of their actual memory performance. Path analyses demonstrated that the subjective confidence of in‐group, but not of out‐group, witnesses predicted participants' accuracy judgments. Conclusions. The results indicate that the validity in judgments of in‐group witnesses can be better than has previously been implied. Investigators may have difficulty distinguishing high‐ and low‐accurate witnesses from other ethnic groups, and they may also systematically underestimate the reliability of ethnic out‐group witnesses. Implications for legal practices are discussed.     

The reliability of eyewitness identification

This study examines the effects of 14 estimator variables (e.g., disguise of robber, exposure time, weapon visibility) and system variables (e.g., lineup instructions, exposure to mugshots) on a number of measures of eyewitness performance: identification accuracy, choosing rates, confidence in lineup choice, relation between confidence and identification accuracy, memory for peripheral details, memory for physical characteristics of target, and time estimates. Subjects viewed a videotaped reenactment of an armed robbery and later attempted an identification. Characteristics of the videotape and lineup task were manipulated. Prominent findings were as follows: identification accuracy was affected by both estimator and system variables including disguise of robber, weapon visibility, elaboration instructions, and lineup instructions. Memory for peripheral details was positively correlated with choosing on the identification task but negatively correlated with identification accuracy.     

The importance of forensic evidence for decisions on criminal guilt

Recent studies have found that the general public perceives forensic evidence to be relatively inaccurate and to involve high levels of human judgement. This study examines how important the general public finds forensic evidence by comparing decisions on guilt and punishment in criminal cases that involve forensic versus eyewitness testimony evidence and examining whether a CSI effect exists. Specifically, this experimental survey study utilized a 2 (crime type: murder or rape) × 4 (evidence type: DNA, fingerprint, victim eyewitness testimony, or bystander eyewitness testimony) ? 1 (no victim testimony for murder scenario) design, yielding seven vignettes scenarios to which participants were randomly assigned. Results indicate that forensic evidence was associated with more guilty verdicts and higher confidence in a guilty verdict. Forensic evidence did not change the expected sentence length and did not generally affect the ideal sentence length. However, for rape, respondents believed that the defendant should receive a longer sentence when forensic evidence was presented but forensic evidence did not alter likely sentence that respondents expected the defendant to receive. The results of this study did not support a CSI effect. Overall, this study suggests that forensic evidence – particularly DNA – has a stronger influence during the verdict stage than the sentencing stage.     

Expert psychological testimony

Experimental psychologists increasingly are asked to give expert testimony in court, especially with regard to issues of eyewitness reliability. Whether or not experimental psychologists should give expert testimony on these matters is a controversial issue. The empirical literature suggests that potential jurors do not have a good understanding of the variables influencing eyewitness accuracy and that they cannot discriminate adequately between accurate and false eyewitness identification testimony. Experiments using expert testimony as a treatment variable, however, have not made a definitive case that expert testimony can benefit trial outcomes. The question of whether or not to give expert testimony must be broadened to consider not only the effects on verdicts but also the effects of expert testimony on the process by which verdicts are reached, the practices of police in subsequent investigations, the public's view of psychology, the practices of judges in subsequent cases, and the interaction between expert testimony and research activities.     

Testing eyewitness memory

This study identifies a memory-testing procedure that is relatively resistant to the documented effects of suggestibility on eyewitness memory. Most studies on suggestibility have used averbal recognition memory test in which the alternative test items are sentences, each to be verified as true or false regarding an originally viewedvisual sequence. In this study, participants were tested with either the verbal recognition memory test typical of studies demonstrating the eyewitness suggestibility effect or a visual recognition memory test. The typical eyewitness suggestibility effect resulted in the verbal test condition. However, with the visual recognition memory test, the hit rates did not significantly differ between the control and misled conditions. Thus, in testing memory for a visual event, a visual recognition memory test is more resistant to the influences of suggestibility than is a verbal test. These results suggest that the original item is preserved in memory, not overwritten by the misleading information. Accordingly, with a visual recognition memory test, the original information is more likely to be recovered with a visual recognition memory test than with a verbal one.     

Co-witness Information Can Have Immediate Effects on Eyewitness Memory Reports

When questioning a reluctant witness, investigators sometimes encourage the witness by providing information about what other witnesses have said. Three experiments were conducted to test the combined effects of such co-witness information and suggestive questioning on the accuracy of eyewitness memory reports. Experiment 1 was analogous to the experience of a witness who receives information from an interviewer or questioner about what other witnesses have already said, whereas Experiments 2 and 3 simulated the situation in which a witness receives information directly from a co-witness. In all three experiments, when participants received incorrect information about a co-witness's response, they were significantly more likely to give that incorrect response than if they received no co-witness information. This effect persevered in a delayed memory test 48 h after the initial questioning session in Experiment 3. Accuracy rates were lowest of all when incorrect co-witness information was paired with questioning that suggested an incorrect response. These results have implications not only for the immediate effects on the accuracy of witnesses' memory reports, but also for the impact that even one such inaccurate report can have on the manner in which a case is investigated by the police or other authorities.