999 resultados para Eyewitness identification


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Mistaken eyewitness identifications of innocent lead to more false convictions in the United States than any other cause. In response to concerns about the reliability of eyewitness evidence, the National Institute of Justice (NIJ) in 1999 published a Guide for the gathering and preservation of eyewitness evidence by law enforcement personnel. Previous research has shown that eyewitness identifications are more accurate when obtained using procedures recommended in the NIJ Guide. This experiment assessed whether informing jurors about the Guide can improve their ability to discriminate between eyewitness identifications likely to be accurate and those likely to be inaccurate and, if so, how to most effectively provide jurors with such information. ^ Seven hundred sixteen U.S. citizens who reported for criminal jury duty participated. Half of the participant jurors read a summary of an armed robbery trial in which the police followed the NIJ Guide when obtaining an eyewitness identification of the defendant. The other half read about an identical case in which the police did not follow the Guide. Jurors received information about the Guide from a court-appointed expert witness, one of the attorneys in the case, the trial judge, the judge in combination with one of the attorneys, or from no one (in the control groups). Jurors then rendered a verdict in the case and answered questions about the evidence in the case. ^ When an expert witness or the judge (either alone or in combination with one of the attorneys) informed jurors about the Guide, the jurors voted to convict defendants likely to be guilty and to acquit defendants likely to be innocent more often than did uninformed jurors assigned to a control group. These data suggest that informing jurors about the NIJ Guide using expert testimony or instructions from a judge will improve the quality and accuracy of jurors' verdict decisions in cases involving eyewitness identification evidence. However, more research is needed to determine whether the judge will remain an effective source of information about the Guide in a longer, more detailed trial scenario and to learn more about the underlying psychological processes governing the effects observed in this experiment. ^

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Given the growing number of wrongful convictions involving faulty eyewitness evidence and the strong reliance by jurors on eyewitness testimony, researchers have sought to develop safeguards to decrease erroneous identifications. While decades of eyewitness research have led to numerous recommendations for the collection of eyewitness evidence, less is known regarding the psychological processes that govern identification responses. The purpose of the current research was to expand the theoretical knowledge of eyewitness identification decisions by exploring two separate memory theories: signal detection theory and dual-process theory. This was accomplished by examining both system and estimator variables in the context of a novel lineup recognition paradigm. Both theories were also examined in conjunction with confidence to determine whether it might add significantly to the understanding of eyewitness memory. ^ In two separate experiments, both an encoding and a retrieval-based manipulation were chosen to examine the application of theory to eyewitness identification decisions. Dual-process estimates were measured through the use of remember-know judgments (Gardiner & Richardson-Klavehn, 2000). In Experiment 1, the effects of divided attention and lineup presentation format (simultaneous vs. sequential) were examined. In Experiment 2, perceptual distance and lineup response deadline were examined. Overall, the results indicated that discrimination and remember judgments (recollection) were generally affected by variations in encoding quality and response criterion and know judgments (familiarity) were generally affected by variations in retrieval options. Specifically, as encoding quality improved, discrimination ability and judgments of recollection increased; and as the retrieval task became more difficult there was a shift toward lenient choosing and more reliance on familiarity. ^ The application of signal detection theory and dual-process theory in the current experiments produced predictable results on both system and estimator variables. These theories were also compared to measures of general confidence, calibration, and diagnosticity. The application of the additional confidence measures in conjunction with signal detection theory and dual-process theory gave a more in-depth explanation than either theory alone. Therefore, the general conclusion is that eyewitness identifications can be understood in a more complete manor by applying theory and examining confidence. Future directions and policy implications are discussed. ^

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"October 1999."

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Showups are a technique of eyewitness identification in which a single suspect is presented to a witness for identification. Showups are controversial. Defense attorneys argue that they are suggestive and place suspects at undue risk of false identification. Prosecutors and police officers argue that showups are an indispensable investigative tool and are no more suggestive than other identification techniques. Are showups probative or perilous? If so, what can be done to improve their accuracy? This investigation converged on this question by addressing three interrelated goals. The first was to examine the effect of two system variables, retention interval and suspect clothing, on showup accuracy. The second was to determine if showups are more suggestive than lineups. The third goal was to explore carryover effects from showups to subsequent lineup identifications. ^ Eyewitness performance was evaluated with the Eyewitness Identification Paradigm. Approximately 500 undergraduate students at FIU witnesses a staged event (i.e., a "crime") in their classrooms and subsequently participated in a showup and/or lineup identification test. Half of the identification tests contained the target (i.e., the "perpetrator") and half contained a target-substitute (i.e., an "innocent suspect"). ^ The results of this study indicated that, overall, showups are not unusually prejudicial and are no more suggestive than lineups. However this study identified two specific conditions under which showups are likely to lead to false identifications of an innocent suspect. First, false identification are likely to occur in showups that are conducted shortly after a crime when the suspect is wearing clothing similar to that worn by the perpetrator. Second, placing an innocent suspect in both a showup and then a lineup substantially increases the chances that the suspect will be falsely identified in the lineup. The implications of these findings for the conduct of eyewitness investigations are discussed. ^

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Despite the intoxication of many eyewitnesses at crime scenes, only four published studies to date have investigated the effects of alcohol intoxication on eyewitness identification performance. While one found intoxication significantly increased false identification rates from target absent showups, three found no such effect using the more traditional lineup procedure. The present study sought to further explore the effects of alcohol intoxication on identification performance and examine whether accurate decisions from intoxicated witnesses could be postdicted by confidence and response times. One hundred and twenty participants engaged in a study examining the effects of intoxication (control, placebo, and mild intoxication) and target presence on identification performance. Participants viewed a simultaneous lineup one week after watching a mock crime video of a man attempting to steal cars. Ethanol intoxication (0.6 ml/kg) was found to make no significant difference to identification accuracy and such identifications from intoxicated individuals were made no less confidently or slowly than those from sober witnesses. These results are discussed with respect to the previous research examining intoxicated witness identification accuracy and the misconceptions the criminal justice system holds about the accuracy of such witnesses.

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Law enforcement officials routinely rely on eyewitness identification evidence to solve crimes. Nonetheless, this form of evidence is prone to errors. Researchers have previously attempted to examine conditions under which such errors can be reduced. The present study examines whether giving witnesses an explicit not sure response option increases the accuracy of lineup identification decisions. 251 participants watched a mock crime video before viewing a lineup that either included the perpetrator, or was made up of innocent suspects. Results indicated that witnesses provided with a not sure option made fewer false identifications, fewer filler identifications, and a similar number of correct identifications as witnesses who were not provided with this option. Furthermore, these benefits occurred regardless of whether witnesses received otherwise biased or unbiased instructions. Results suggest that the inclusion of an explicit not sure response option is a simple procedure that can increase the quality of eyewitness lineup decisions.

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This review examines the overall accuracy of social perception across several research topics and identifies factors that inf luence the accuracy of social perception. Findings from 14 meta-analyses examining topics such as social/personality judgments, health judgments, legal judgments, and academic/vocational judg-ments were obtained. Social perception accuracy was generally moderate, yielding an average effect size (r) of .32. However, individual meta-analytic effects varied widely, with some topics yielding small effects (e.g., lie detection, eyewitness identification) and other topics yielding large effects (e.g., educational judgments, health judgments). Several moderators of social perception accuracy were identified, includ-ing the nature of the information source, familiarity of the target, type of personality trait, and severity of the outcome being judged. These findings provide a comprehensive summary and novel integration of disparate findings on the accuracy of social perception. Concluding remarks highlight avenues for future research and call for cross-disciplinary collaborations that would enhance our understanding of social perception.

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Previous research has examined the validity of behavioral assumptions underlying the presumed effectiveness of safeguards against erroneous conviction resulting from mistaken eyewitness identification. In keeping with this agenda, this study examined juror sensitivity to lineup suggestiveness in the form of foil, instruction, and presentation biases and whether expert psychological testimony further sensitizes jurors to the factors that influence the likelihood of false identifications. One hundred and sixty jury eligible citizens watched versions of a videotaped trial that included information about the identification of the defendant by an eyewitness and that varied the suggestiveness of the eyewitness identification procedure. In addition, half of the mock-jurors heard the testimony of an expert psychologist regarding the factors that influence lineup suggestiveness. Mock-jurors rendered individual verdicts, rated the defendant's culpability and the suggestiveness and fairness of the identification procedure. Results indicated that jurors are somewhat sensitive to foil bias but are insensitive to instruction and presentation biases. No evidence was found to suggest that expert testimony leads to juror skepticism or juror sensitization. These results question the effectiveness of cross-examination and expert testimony as safeguards against erroneous convictions resulting from mistaken identification. ^

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The current study investigated the exculpatory value of alibi evidence when presented together with various types of incriminating evidence. Previous research has reported that alibi evidence could weaken the effects of DNA evidence and eyewitness identification. The present study assessed the effectiveness of alibi evidence in counteracting defendant's confession (experiment 1) and eyewitness evidence (experiment 2). In experiment 1, three levels of alibi evidence (none, weak, strong) were combined with three levels of confession evidence (voluntary, elicited under low pressure, elicited under high pressure). Results indicated significant main effects of confession and alibi and an alibi by confession interaction. Of participants exposed to high-pressure confession, those in the strong alibi condition rendered lower guilt estimates than those in the no alibi condition. In experiment 2, three levels of alibi were combined with two levels of eyewitness evidence (bad view, good view). A main effect of alibi was obtained, but no interaction between alibi and eyewitness evidence. ^ An explanation of this pattern is based in part on the Story Model (Pennington & Hastie, 1992) and a novel “culpability threshold” model of juror decision-making. The Story Model suggests that jurors generate verdict stories (interpretations of events consistent with a guilty or not guilty verdict) based on trial evidence. If the evidence in favor of guilt exceeds jurors' threshold for perceiving culpability, jurors will fail to properly consider exonerating evidence. However, when the strength of incriminating evidence does not exceed the jurors' threshold, they are likely to give appropriate consideration to exculpatory evidence in their decisions. ^ Presentation of a reliable confession in Experiment 1 exceeded jurors' culpability threshold and rendered alibi largely irrelevant. In contrast, presentation of a high-pressure confession failed to exceed jurors' culpability threshold, so jurors turned to alibi evidence in their decisions. Similarly, in the second experiment, eyewitness evidence (in general) was not strong enough to surpass the culpability threshold, and thus jurors incorporated alibi evidence in their decisions. A third study is planned to further test this “culpability threshold” model, further explore various types of alibi evidence, and clarify when exculpatory evidence will sufficiently weaken the prosecution's “story.” ^

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This research explored similarity ratings as an alternative to identifications with regards to eyewitness evidence. This involved replacing the concept of binary identity decisions with continuum-based similarity judgments. Preliminary evidence suggested that a relationship exists between similarity and identity, and that ratings offer a number of advantages over identifications.

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The problem of determining the script and language of a document image has a number of important applications in the field of document analysis, such as indexing and sorting of large collections of such images, or as a precursor to optical character recognition (OCR). In this paper, we investigate the use of texture as a tool for determining the script of a document image, based on the observation that text has a distinct visual texture. An experimental evaluation of a number of commonly used texture features is conducted on a newly created script database, providing a qualitative measure of which features are most appropriate for this task. Strategies for improving classification results in situations with limited training data and multiple font types are also proposed.