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.     

Polygraph Testimony and Juror Judgments: A Comparison of the Guilty Knowledge Test and the Control Question Test1

The present experiment investigated the impact of the Control Question Test (CQT) and the Guilty Knowledge Test (GKT) on the verdicts of mock jurors. Although studies have indicated that polygraph evidence has little influence on jurors' verdicts (Cavoukian & Heselgrave, 1980; Spanos, Myers, Dubreuil, & Pawlak, 1992–1993), no research has previously distinguished between the different types of polygraph tests and their impact on juror verdicts. In the present study, jurors were shown a videotape of a simulated rape-murder trial that contained either CQT polygraph evidence, GKT polygraph evidence, or no polygraph evidence. No differences were found among the 3 conditions for either jury verdicts or individual juror verdicts, and jurors tended to rate both forms of polygraph testimony below other forms of equally suspect evidence, such as eyewitness testimony, in its influence on their decision-making process.     

Expert testimony and jury decision making: An empirical analysis

This experiment examines the influence of expert psychological testimony on juror decision making in eyewitness identification cases. Experienced jurors and undergraduate mock jurors viewed versions of a videotaped trial, rated the credibility of the eyewitness and the strength of the prosecution's and defense's cases, and rendered verdicts. In the absence of expert testimony jurors were insensitive to eyewitness evidence. Expert testimony improved juror sensitivity to eyewitness evidence without making them more skeptical about the accuracy of the eyewitness identification. Few differences emerged between the experienced jurors and undergraduate mock jurors.     

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.     

A Lay Perspective on the Accuracy of Eyewitness Testimony1

To understand more about what laypeople think they “know” about eyewitness testimony, 276 jury-eligible university students were asked to indicate what factors they believe affect the accuracy of eyewitness testimony. In contrast to the large proportion of eyewitness-memory research that concerns system variables, the lay respondents overwhelmingly generated factors related to estimator variables, while system-variable factors such as police questioning and identification procedures were rarely mentioned. Respondents also reported that their own common sense and everyday life experiences were their most important sources of information about the accuracy of eyewitness testimony. Not only do these results clarify the need for further research on the lay perspective of eyewitness testimony, but they also provide some insight into the way in which many jurors might approach cases involving eyewitness evidence.     

Jurors' Decisions in Trials of Battered Women Who Kill: The Role of Prior Beliefs and Expert Testimony1

The present research explored the influence of four factors on mock jurors' decisions in a homicide trial involving a battered woman who killed her abusive husband: (a) jurors' preexisting beliefs about wife abuse, (b) the presence of expert testimony on the battered woman syndrome, (c) jurors' beliefs in a just world, and (d) gender. Mock jurors listened to a trial involving a woman who had killed her abuser, which either contained expert testimony or did not, and then rendered various judgments about the case. Results indicated that those individuals who were more informed about the dynamics of abuse and those exposed to the expert testimony, compared to their respective counterparts, were more believing of the battered woman's account of what occurred. In general, weak believers in a just world were more lenient in their judgments, with verdicts of not guilty being associated with weaker beliefs in a just world than guilty verdicts. Weak believers in a just world also felt that the expert testimony applied more to the defendant than did strong believers. Finally, women who were weak believers in a just world were less likely to hold the defendant responsible for the events and to be more informed about the dynamics of abuse following the experiment.     

The Timing of the Defense Opening Statement: Don't Wait Until the Evidence Is in1

Defense attorneys often reserve their opening statements until after presentation of evidence by the prosecution, a practice advocated by some experts. The current study, involving 291 subjects, varied the timing of the defense attorney's opening statement so that it preceded the prosecutor's opening statement, immediately followed the prosecutor's opening statement, or was reserved until after the prosecutor's case presentation. The type of opening statement (content vs. noncontent) and the testimony (altered vs. unaltered) were varied for purposes of increasing generalization. Materials were based on an actual case of auto theft and were presented in written form complete with judge's instructions. The results showed that subjects perceived eyewitness testimony, the prosecutor's opening statement, the prosecutor's closing statement, the defense attorney's closing statement, and the effectiveness of the attorneys differently depending on the timing of the opening statement. Each of these items favored the defense more than the prosecution if the defense opening statement was earlier rather than later. These effects did not interact with type of opening statement or the testimony alteration variable. Individual verdicts, when weighted by the subjects' confidence in their verdicts, were also affected by the timing variable with verdicts more favorable to the defense when the defense opening statement was given earlier rather than later. The consistency with which the timing variable affected subjects' impressions suggests that defense attorneys who take their first opportunity to make an opening statement, rather than delay, end up with a stronger case for their client. Possible exceptions to this conclusion are discussed.     

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.     

The Discrediting Effect in Eyewitness Testimony1

Loftus (1974) had subjects read summaries of criminal trials that contained the testimony of either credible or discredited prosecution eyewitnesses, and found no effect of discrediting an eyewitness. Instead, almost as many subjects voted guilty with a discredited eyewitness as with a credible eyewitness; this led Loftus to the conclusion that jurors tend to overbelieve eyewitness testimony. Loftus's conclusion was subsequently challenged by others who reported a strong discrediting effect. A series of three experiments using college students was conducted to explore the characteristics of trial summaries that might account for the discrepancy in results, such as inclusion of judicial instructions concerning proof beyond a reasonable doubt, or an eyewitness's reaffirmation of his testimony following discrediting. In all cases, a strong discrediting effect was found. Apparently the discrediting effect appears regardless of wide variation in content of trial summaries. The present data do not support the overbelief claim.     

Witnesses and Their Testimony: Effects of Ordering on Juror Verdicts1

Thibaut and Walker's claim that criminal courtroom proceedings are subject to pervasive recency effects was experimentally investigated. Previous research on order effects in a legal setting is critically reviewed; it is argued that this research fails to provide adequate simulation of courtroom protocol. An experiment was designed to retain the structure of a criminal trial while manipulating witness and testimony order. In contrast to earlier research, primacy effects were found. The greatest number of guilty verdicts by simulated jurors occurred when the strongest “guilty” witnesses and “guilty” testimony by these witnesses came first. These results are discussed with respect to (a) witness and testimony order, (b) length of case, and (c) type of case used.     

What US judges know and believe about eyewitness testimony

In a survey, 160 US judges indicated their knowledge and beliefs about eyewitness testimony. Although correct on some issues, judges were often wrong on important issues such as whether at trial eyewitness confidence is a good indicator of eyewitness accuracy, and if jurors can distinguish accurate from inaccurate witnesses. Increased knowledge was associated with: a willingness to permit legal safeguards, including expert testimony at trial; a belief that jurors have limited knowledge of eyewitness factors; a reluctance to convict defendants solely from eyewitness testimony; a more accurate estimate of the extent to which wrongful convictions result from eyewitness error; and a belief that judges need more eyewitness training. Additional training about factors and procedures that affect eyewitness accuracy may help judges reduce the number of wrongful convictions. Copyright © 2004 John Wiley & Sons, Ltd.     

Habla Ingles? The Effects of Language Translation on Simulated Juror Decisions1

Two studies were conducted in which college students, acting as simulated jurors, heard the testimony of a defendant in an assault case. The testimony was presented in English or in another language (Spanish in Study 1 and Thai in Study 2) which was translated into English by an interpreter. In Study 1, non-Hispanics judged the defendant to be more guilty than did Hispanics when the defendant's testimony was presented in Spanish than when it was presented in English. This bias was offset when the judge's instructions admonished the jurors to ignore the fact that the defendant's testimony was translated. Similarly, in Study 2, subjects (all non-Thai) judged the defendent more guilty when his testimony was presented in Thai than when it was presented in English. Again, this bias was eliminated by the judge's instructions to the jurors to ignore the fact that the testimony was translated. The increased guilty verdicts for defendants who did not testify in English appeared to be due to prejudice and language ethnocentrism, the belief that defendants in U.S. courts should speak English.     

The Psychology of Eyewitness Testimony: A Comparison of Experts and Prospective Jurors

To compare people's beliefs about eyewitness testimony with expert opinion, 79 college students and community adults filled out a questionnaire in which they reported whether they agreed or disagreed with 21 statements previously used in a survey of eyewitness experts (Kassin, Ellsworth, & Smith, 1989). The results indicated that there was a significant inter-item correlation of agreement rates but that subjects differed from the experts on 15 of these items. For courts seeking to determine the extent to which juries need assistance in their evaluations of eyewitness evidence, these findings offer a tentative list of topics worthy of either expert testimony or cautionary instructions from the judge.     

A Comparison of What U.S. Judges and Students Know and Believe About Eyewitness Testimony

We compared what 160 U.S. judges, 57 law students, and 121 undergraduates know and believe about factors affecting the accuracy of eyewitness testimony. Judges were no more knowledgeable than were undergraduates, and both groups were less knowledgeable than were law students. For all 3 groups, increased knowledge of eyewitness factors was associated with beliefs that might reduce wrongful convictions. Participants in all 3 groups underestimated what potential jurors know about eyewitness testimony. The results suggest that increasing judges' knowledge of eyewitness testimony might help them to reduce wrongful convictions and to more accurately assess when eyewitness experts are needed. The results also suggest that law schools need to do a better job of educating law students about eyewitness testimony.