Degree of Detail of Eyewitness Testimony and Mock Juror Judgments1

The influence of the degree of detail of eyewitness testimony on two sides of a court case was investigated in two experiments. In the first experiment subject-jurors read a civil court case involving an automobile-pedestrian accident. The plaintiff and the defendant presented conflicting eyewitness accounts. Judgments of the relative credibility of the eyewitnesses on each side and the percentage of negligence of the parties were influenced by the relative degree of detail of the eyewitness testimony on each side. In the second experiment subject-jurors read a criminal court case involving robbery and murder. The prosecution and defense presented conflicting eyewitness accounts. The degree of detail of the prosecution eyewitness testimony influenced judgments of guilt and judgments of the credibility of the eyewitnesses. An examination of the reasons for verdicts and credibility judgments revealed that some subjects inferred that an eyewitness who gave testimony with a greater degree of detail had a better memory for the trivial details and the culprit than an eyewitness who gave testimony with a lesser degree of detail. Implications of these results for the legal system are discussed.     

Testifying on Eyewitness Reliability: Expert Advice Is Not Always Persuasive1

This study investigates the impact of different types of expert testimony regarding the unreliability of eyewitness identification. In two hypothetical court cases involving eyewitnesses, expert testimony was presented that was either sample-based (presenting the results of a research program on eyewitness identification) or person-based (presenting information about the particular eyewitness under consideration); the expert either offered causal explanations for his unreliability claim or failed to do so. Two additional control groups (with and without eye-witness identification) were not presented with any expert testimony. The results indicate that subjects who had been confronted with an expert statement made more lenient judgments about the offender but did not discount the eyewitness identification completely. Sample-based information had a moderate impact on the subjects' judgments, regardless of whether or not causal explanations were given. Person-based testimony was the most influential type of expert advice when a causal explanation was provided but the least influential one when no reasons were given. The practical (international differences in admissibility of expert testimony) and theoretical implications (processing of base-rate information) of these findings are discussed.     

Preventing the Application of Stereotypic Biases in the Courtroom: The Role of Detailed Testimony1

To determine whether detailed testimony has equivalent effects on judgments of stereotyped and nonstereotyped defendants, subjects read a synopsis of a criminal court case in which the defendant either was a stereotyped offender or was not. Additionally, the degree of detail in the prosecution testimony and defense testimony was varied. Results indicated that defendant stereotypicality had a greater impact under conditions in which witnesses provided equal amounts of detail in their testimony. When witnesses differed in the degree of detail in their testimony, the stereotypicality of the defendant was disregarded and judgments favored the witness who provided greater detail. These findings suggest that stereotype application is not inevitable; rather, stereotypes may bias jurors' decision-making processes when the quality and quantity of the evidence does not easily lead to a confident judgment.     

How jurors use and misuse character evidence

The Federal Rules of Evidence allow defendants to offer testimony about their good character, but that testimony can be impeached with cross-examination or a rebuttal witness. It is assumed that jurors use the defense's character evidence (CE) to form guilt and conviction judgments but use impeachment evidence only to assess the character witness's credibility. Two experiments tested these assumptions by presenting mock jurors with various forms of CE and impeachment. Participants made trait ratings for the character witness and defendant and guilt and conviction judgments. Positive CE did not affect guilt or conviction judgments, but cross-examination caused a backlash in which judgments were harsher than when no CE was given. Using path analysis, the authors tested a model of the process by which CE and impeachment affect defendant and witness impressions and guilt and conviction judgments. Implications for juror decision making are discussed.     

The Influence of Eyewitness Nonidentifications on Mock-Jurors' Judgments of a Court Case1

Two experiments examined the effect of an eyewitness nonidentificution on mock-jurors' verdicts in robbery cases, as well as the effects of number of identifying eyewitnesses and status of the identifying witness (victim or bystander). Subjects read court case summaries that included variable eyewitness evidence and constant alibi, circumstantial, and character evidence. In Experiment 1, frequency of guilty verdicts was significantly less when an eyewitness testified in court that the defendant was not the perpetrator, even when this nonidentification opposed two positive identifications. In Experiment 2, a low guilty rate was again associated with the presence of a nonidentifier, but only when the nonidentifier actually testified in court and stipulated that the defendant is “not the man.” On the average, 70% of the jurors delivered guilty verdicts when both the victim and bystander gave identifying testimony, whereas 12.5% delivered guilty verdicts when the bystander gave opposing nonidentifying testimony. Guilty rates were unaffected by the identifying eyewitness' status and (in Experiment 2, but not Experiment 1) were higher when there were two (vs. one) identifying eyewitnesses.     

An archival study of eyewitness memory of the Titanic's final plunge

A handful of real-life studies demonstrate that most eyewitnesses accurately recall central details (i.e., the gist of what happened) from traumatic events. The authors evaluated the accuracy of archival eyewitness testimony from survivors of the Titanic disaster who witnessed the ship's final plunge. The results indicate that most eyewitness testimony (15 eyewitnesses of 20) is consistent with forensic evidence that demonstrates that the Titanic was breaking apart while it was still on the ocean's surface. Despite the methodological limitations of archival research, the authors provide evidence from a single-occurrence traumatic event (with a large-scale loss of life) that the majority of eyewitnesses accurately recall central details.     

An Archival Study of Eyewitness Memory of the Titanic's Final Plunge

A handful of real-life studies demonstrate that most eyewitnesses accurately recall central details (i.e., the gist of what happened) from traumatic events. The authors evaluated the accuracy of archival eyewitness testimony from survivors of the Titanic disaster who witnessed the ship's final plunge. The results indicate that most eyewitness testimony (15 eyewitnesses of 20) is consistent with forensic evidence that demonstrates that the Titanic was breaking apart while it was still on the ocean's surface. Despite the methodological limitations of archival research, the authors provide evidence from a single-occurrence traumatic event (with a large-scale loss of life) that the majority of eyewitnesses accurately recall central details.     

Psychological differentiation and the evaluation of juridic information: Cognitive and affective consequences

The cognitive and evaluative involvements of field dependence-independence in the processing of available information were examined in two experiments. In Experiment 1, ninety-six female undergraduates were assigned to field-dependent and field-independent conditions (via a median split on Embedded Figures Test scores). Half were given information about the trial of a man accused of attempted manslaughter that was suggestive of guilt; the other half received information suggestive of innocence. They were asked to indicate their confidence in the guilt or innocence of the defendant, and to recall arguments from the information they received. Field-dependent subjects were significantly more extreme in their confidence judgments, particularly in the exonerating conditions. They also showed nonsignificantly poorer recall. In Experiment 2, forty-eight subjects from Experiment 1 were given arguments biased in the opposite direction of their original sets. Field-dependent subjects were significantly more likely to shift their confidence judgments and report discomfort when the new information suggested innocence, and to underrecall new information when it suggested guilt. Field-dependent subjects again showed poorer recall. The results of both experiments were discussed in terms of their support for a field-dependence value bias and encoding deficiency.     

Repetition, not number of sources, increases both susceptibility to misinformation and confidence in the accuracy of eyewitnesses

Are claims more credible when made by multiple sources, or is it the repetition of claims that matters? Some research suggests that claims have more credibility when independent sources make them. Yet, other research suggests that simply repeating information makes it more accessible and encourages reliance on automatic processes—factors known to change people's judgments. In Experiment 1, people took part in a “misinformation” study: people first watched a video of a crime and later read eyewitness reports attributed to one or three different eyewitnesses who made misleading claims in either one report or repeated the same misleading claims across all three reports. In Experiment 2, people who had not seen any videos read those same reports and indicated how confident they were that each claim happened in the original event. People were more misled by—and more confident about—claims that were repeated, regardless of how many eyewitnesses made them. We hypothesize that people interpreted the familiarity of repeated claims as markers of accuracy. These findings fit with research showing that repeating information makes it seem more true, and highlight the power of a single repeated voice.     

Effects of the Inclusion and Refutation of Peripheral Details on Eyewitness Credibility

The present study examines the effects of including trivial details in eyewitness testimony on witness credibility, as well as the effects of discrediting presented details. Participants ( N = 155) read 2 brief, contradictory depositions from fictional witnesses about a fictional car accident. One of the depositions included a short set of details unrelated to the accident itself. After participants rated the credibility of the witnesses, the trivial details were refuted and the participants rated the credibility of the witnesses again. Contrary to previous research (Bell & Loftus, 1989), the inclusion of trivial details had no effect on witness credibility. However, significant effects on witness credibility were obtained when the details were refuted. As expected, the credibility of the witness presenting the trivial details significantly decreased after detail refutation. More interestingly, refutation appeared to increase the credibility of the other witness.     

Not too ‘shy’ to help catch a thief: Recall memory of shy versus non-shy witnesses

Witness shyness was examined to determine its impact on recall accuracy in two experiments. It was hypothesized that shyness would facilitate witness accuracy, under some conditions. In Experiment 1, witnesses were asked to respond to directed recall questions probing crime event and culprit details. Non-shy and shy witnesses produced comparable accuracy rates when describing the culprit. In contrast, non-shy witnesses were more accurate when describing crime environment details than shy witnesses. In Experiment 2, arousal was manipulated and a free recall approach was used to assess recall accuracy. Under low arousal, shy witnesses were more accurate at describing the culprit than non-shy witnesses, whereas, non-shy witnesses were more accurate at describing crime details than shy witnesses. Under high arousal, differences in accuracy were not observed across shy and non-shy witnesses.     

Post‐identification feedback: exploring the effects of sequential photospreads and eyewitnesses' awareness of the identification task

Two experiments tested whether the sequential photospread procedure would protect eyewitnesses against memory distortion from post‐identification feedback. In Experiment 1, participants (N = 245) watched a videotaped event and then viewed a sequential or simultaneous target‐absent photospread. After their identification, participants were randomly assigned to hear confirming feedback ‘Good, you identified the suspect.’ or no feedback (control). Participants then completed a questionnaire assessing testimony‐relevant retrospective judgments. Post‐hoc analyses revealed that the sequential photospread only protected against post‐identification feedback effects for participants who reported that, while they watched the video, they did not expect to make an identification. A second experiment (N = 320) was conducted to manipulate expectations about the identification task and the presence of the target. This experiment revealed that the post‐identification feedback effect persists across witnesses' expectations and lineup type. Copyright © 2006 John Wiley & Sons, Ltd.     

How the Defendant's Emotion Level Affects Mock Jurors' Decisions When Presentation Mode and Evidence Strength Are Varied1

Two experiments (N= 443) were conducted to investigate the effects of a defendant's emotion level during testimony on mock jurors' decisions. In Experiment 1, the defendant's level of emotion (low, moderate, high) and mode of presentation (audio, video) were varied. The defendant displaying a low level, as opposed to a higher level of emotion was perceived as more guilty and less credible. In Experiment 2, using only the video mode, emotion level and evidence strength (strong, weak) were varied. Defendant emotion level tended to affect jurors' decisions only when the evidence against the defendant was weak (i.e., a stronger display of emotion was associated with a lower proportion of guilty verdicts, shorter sentence assignments, and perceptions of a more honest defendant). Path analyses for both experiments indicate that the effects of emotion on perceived guilt level are mediated by perceptions of the defendant (e.g., the defendant's level of honesty). Implications of using defendant emotion level for determining guilt are discussed.     

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.     

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.     

Evaluating Identification Evidence from Multiple Eyewitnesses

When two or more eyewitnesses provide identification evidence in a given investigation, their testimony will be characterized either by unanimity or by contradictions. In the present research, nominal groups of several sizes were constructed from the distributions of individual responses in a variety of previous studies. It was found that both unanimity and contradictions could be expected to occur with considerable frequency. When unanimity occurred, the unanimous response was very likely to be accurate, particularly in large groups. When contradictions occurred, the most common, or modal, response was most probably accurate, particularly when four or more witnesses endorsed the modal position. These and several subsidiary findings resulted largely from the fact that individual errors were randomly distributed across many different incorrect response options. Consequently, even when eyewitnesses were generally inaccurate, the correct option was still chosen more frequently than any single incorrect option. Distinctions between the implications of individual vs. multiple eyewitness testimony were discussed.