Eyewitness Evidence Improving Its Probative Value

Psychological Science in the Public Interest 11/2006; 7(2). DOI: 10.1111/j.1529-1006.2006.00027.x


The criminal justice system relies heavily on eyewitnesses to determine the facts surrounding criminal events. Eyewitnesses may identify culprits, recall conversations, or remember other details. An eyewitness who has no motive to lie is a powerful form of evidence for jurors, especially if the eyewitness appears to be highly confident about his or her recollection. In the absence of definitive proof to the contrary, the eyewitness's account is generally accepted by police, prosecutors, judges, and juries. However, the faith the legal system places in eyewitnesses has been shaken recently by the advent of forensic DNA testing. Given the right set of circumstances, forensic DNA testing can prove that a person who was convicted of a crime is, in fact, innocent. Analyses of DNA exoneration cases since 1992 reveal that mistaken eyewitness identification was involved in the vast majority of these convictions, accounting for more convictions of innocent people than all other factors combined. We review the latest figures on these DNA exonerations and explain why these cases can only be a small fraction of the mistaken identifications that are occurring. Decades before the advent of forensic DNA testing, psychologists were questioning the validity of eyewitness reports. Hugo Münsterberg's writings in the early part of the 20th century made a strong case for the involvement of psychological science in helping the legal system understand the vagaries of eyewitness testimony. But it was not until the mid- to late 1970s that psychologists began to conduct programmatic experiments aimed at understanding the extent of error and the variables that govern error when eyewitnesses give accounts of crimes they have witnessed. Many of the experiments conducted in the late 1970s and throughout the 1980s resulted in articles by psychologists that contained strong warnings to the legal system that eyewitness evidence was being overvalued by the justice system in the sense that its impact on triers of fact (e.g., juries) exceeded its probative (legal-proof) value. Another message of the research was that the validity of eyewitness reports depends a great deal on the procedures that are used to obtain those reports and that the legal system was not using the best procedures. Although defense attorneys seized on this nascent research as a tool for the defense, it was largely ignored or ridiculed by prosecutors, judges, and police until the mid 1990s, when forensic DNA testing began to uncover cases of convictions of innocent persons on the basis of mistaken eyewitness accounts. Recently, a number of jurisdictions in the United States have implemented procedural reforms based on psychological research, but psychological science has yet to have its fullest possible influence on how the justice system collects and interprets eyewitness evidence. The psychological processes leading to eyewitness error represent a confluence of memory and social-influence variables that interact in complex ways. These processes lend themselves to study using experimental methods. Psychological science is in a strong position to help the criminal justice system understand eyewitness accounts of criminal events and improve their accuracy. A subset of the variables that affect eyewitness accuracy fall into what researchers call system variables, which are variables that the criminal justice system has control over, such as how eyewitnesses are instructed before they view a lineup and methods of interviewing eyewitnesses. We review a number of system variables and describe how psychological scientists have translated them into procedures that can improve the probative value of eyewitness accounts. We also review estimator variables, variables that affect eyewitness accuracy but over which the system has no control, such as cross-race versus within-race identifications. We describe some concerns regarding external validity and generalization that naturally arise when moving from the laboratory to the real world. These include issues of base rates, multicollinearity, selection effects, subject populations, and psychological realism. For each of these concerns, we briefly note ways in which both theory and field data help make the case for generalization.
© 2006 Association for Psychological Science.

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    • "Over the years, slightly different variants of the Cognitive Interview have been adopted, but many of them involve the following stages (for review, see Memon et al., 2010): (a) rapport building between the interviewer and the witness; (b) context reinstatement: witness being asked to mentally reconstruct the context of the witnessed event; (c) report everything: witness being instructed to recall everything about the event; (d) change temporal order: witness being instructed to recall the event in a different temporal order, such as from the last event to the first; and (e) focused retrieval: witness being asked to expand on his or her description of recalled details. Many studies have shown that the Cognitive Interview is superior to a standard interview in increasing recall of correct information , but a few studies have also found that the Cognitive Interview is associated with a slight increase in the reporting of incorrect details (for a review, see Köhnken, Milne, Memon, & Bull, 1999; Wells et al., 2006). Despite the wealth of studies examining the effectiveness of the Cognitive Interview, relatively few have investigated the influence of this technique on older adults' recall (e.g., Dornburg & McDaniel, 2006; Holliday et al., 2012; McMahon, 2000; Mello & Fisher, 1996; Searcy, Bartlett, Memon, & Swanson, 2001; Wright & Holliday, 2007). "
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    ABSTRACT: In 2 experiments, younger and older adults witnessed a simulated robbery, received misleading information about the event, and then were interviewed with the Cognitive Interview about their memory for the robbery. In both experiments, older adults were disproportionately more confident than younger adults in the accuracy of incorrect information that they recalled than in the accuracy of correct information. Critically, this age-related increase in high-confidence errors occurred even in comparison with younger adults who were matched with older adults on the overall amount and accuracy of the information remembered about the robbery. In addition, Experiment 2 showed that retrieval warnings to disregard the misinformation were just as effective in older adults as compared with younger adults at reducing the reporting of misleading information. Finally, both experiments showed that across the multiple retrieval stages of the Cognitive Interview, the final retrieval stage is roughly half as effective for older adults relative to younger adults at eliciting previously unreported information. These results indicate that investigators have much less to gain from older adults than they do from younger adults with repeated inquiries (during the same session) about a witnessed event. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
    Psychology and Aging 12/2014; 30(1). DOI:10.1037/a0038492 · 2.73 Impact Factor
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    • "In many of these cases, eyewitnesses provide an accurate method for proving the identity of a person that was seen at a crime scene. However, many eyewitnesses also make honest errors under these conditions, by mistakenly identifying innocent suspects for a previously seen perpetrator (see, e.g., Davies & Griffiths, 2008; Huff, Rattner, & Sagarin, 1986; Wells, Memon, & Penrod, 2006). A fundamental problem in criminal person identification therefore concerns the extent to which it is possible to assess the accuracy of an eyewitness's memory for a sought-after perpetrator. "
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    ABSTRACT: The time available for viewing a perpetrator at a crime scene predicts successful person recognition in subsequent identity line-ups. This time is usually unknown and must be derived from eyewitnesses' duration estimates. This study therefore compared the estimates that different individuals provide for crimes. We then attempted to determine the accuracy of these durations by measuring observers' general time estimation ability with a set of estimator videos. Observers differed greatly in their ability to estimate time, but individual duration estimates correlated strongly for crime and estimator materials. This indicates that it might be possible to infer unknown durations of events, such as criminal incidents, from a person's ability to estimate known durations. We also measured observers' eye movements to a perpetrator during crimes. Only fixations on a perpetrator's face related to eyewitness accuracy, but these fixations did not correlate with exposure estimates for this person. The implications of these findings are discussed. Copyright © 2013 John Wiley & Sons, Ltd.
    Applied Cognitive Psychology 03/2014; 28(2). DOI:10.1002/acp.2986 · 1.67 Impact Factor
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    • "The seminal studies, which showed significant benefits and nonsignificant costs, combined with a theory that appeared to predict precisely that pattern, created a compelling and self-reinforcing scientific story that has dominated the field for 30 years. Indeed, as Wells et al. (2006) have noted, the theory, and its predicted no-cost pattern of results, " has permeated the literature on lineups " (p. 61). "
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    ABSTRACT: Scientists in many disciplines have begun to raise questions about the evolution of research findings over time (Ioannidis in Epidemiology, 19, 640-648, 2008; Jennions & Møller in Proceedings of the Royal Society, Biological Sciences, 269, 43-48, 2002; Mullen, Muellerleile, & Bryan in Personality and Social Psychology Bulletin, 27, 1450-1462, 2001; Schooler in Nature, 470, 437, 2011), since many phenomena exhibit decline effects-reductions in the magnitudes of effect sizes as empirical evidence accumulates. The present article examines empirical and theoretical evolution in eyewitness identification research. For decades, the field has held that there are identification procedures that, if implemented by law enforcement, would increase eyewitness accuracy, either by reducing false identifications, with little or no change in correct identifications, or by increasing correct identifications, with little or no change in false identifications. Despite the durability of this no-cost view, it is unambiguously contradicted by data (Clark in Perspectives on Psychological Science, 7, 238-259, 2012a; Clark & Godfrey in Psychonomic Bulletin & Review, 16, 22-42, 2009; Clark, Moreland, & Rush, 2013; Palmer & Brewer in Law and Human Behavior, 36, 247-255, 2012), raising questions as to how the no-cost view became well-accepted and endured for so long. Our analyses suggest that (1) seminal studies produced, or were interpreted as having produced, the no-cost pattern of results; (2) a compelling theory was developed that appeared to account for the no-cost pattern; (3) empirical results changed over the years, and subsequent studies did not reliably replicate the no-cost pattern; and (4) the no-cost view survived despite the accumulation of contradictory empirical evidence. Theories of memory that were ruled out by early data now appear to be supported by data, and the theory developed to account for early data now appears to be incorrect.
    Psychonomic Bulletin & Review 11/2013; 21(2). DOI:10.3758/s13423-013-0516-y · 2.99 Impact Factor
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