Amina Memon

Eyewitness Evidence: Improving Its Probative Value

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 eyewitnesss 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 Münsterbergs 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.

On the "general acceptance" of eyewitness testimony research: A new survey of the experts.

In light of recent advances, this study updated a prior survey of eyewitness experts (S. M. Kassin, P. C. Ellsworth, & V. L. Smith, 1989). Sixty-four psychologists were asked about their courtroom experiences and opinions on 30 eyewitness phenomena. By an agreement rate of at least 80%, there was a strong consensus that the following phenomena are sufficiently reliable to present in court: the wording of questions, lineup instructions, confidence malleability, mug-shot-induced bias, postevent information, child witness suggestibility, attitudes and expectations, hypnotic suggestibility, alcoholic intoxication, the crossrace bias, weapon focus, the accuracy-confidence correlation, the forgetting curve, exposure time, presentation format, and unconscious transference. Results also indicate that these experts set high standards before agreeing to testify. Despite limitations, these results should help to shape expert testimony so that it more accurately represents opinions in the scientific community.

The cognitive interview: A meta-analysis

Abstract A meta-analysis was performed on the effects of the cognitive interview on correct and incorrect recall. The database comprised 42 studies with 55 individual comparisons involving nearly 2500 interviewees. A strong overall effect size was found for the increase of correctly recalled details with the cognitive interview compared to a control interview (d = 0.87). The overall effect size for the increase in incorrect details, although considerably smaller, was also significant toward the cognitive interview (d = 0.28). However, the accuracy rates (proportion of correct details relative to the total amount of details reported) were almost identical in both types of interview (85% for the cognitive interview and 82% for standard interviews, respectively). Taking methodological factors into consideration it was found that effect sizes for correct details were larger if staged events were used as the to-be-remembered episode (as compared to video films) and if the interviewees actively participated in ...

Imagination Can Create False Autobiographical Memories

Previous studies have shown that imagining an event can alter autobiographical beliefs. The current study examined whether it can also create false memories. One group of participants imagined a relatively frequent event and received information about an event that never occurs. A second group imagined the nonoccurring event and received information about the frequent event. One week before and again 1 week immediately after the manipulation, participants rated the likelihood that they had experienced each of the two critical events and a series of noncritical events, using the Life Events Inventory. During the last phase, participants were also asked to describe any memories they had for the events. For both events, imagination increased the number of memories reported, as well as beliefs about experiencing the event. These results indicate that imagination can induce false autobiographical memories.

Say it to my face: Examining the effects of socially encountered misinformation

Objectives. Errors in eyewitness accounts can occur when a witness comes into contact with post-event ‘misinformation’. A common way to encounter misinformation is through face-to-face interaction, in particular, via conversation with other individuals who also witnessed the crime. The current research compares this kind of misinformation with the non-social post-event narrative method typically employed in laboratory studies. Method. Young (17–33 years) and older (58–80 years) adults viewed a simulated crime event on video and were later exposed to four items of misinformation about it. The misinformation items were either introduced as part of a discussion about the event with a confederate or were embedded within a written narrative about the event that participants were asked to read. A questionnaire containing 20 items about the event was given to participants before and after the experimental manipulation. Results. Participants were less accurate than controls on questionnaire items after encountering misinformation. More importantly, misinformation encountered socially was significantly more misleading than misinformation from a non-social source. This was true for both young and older adults. Conclusion. Misinformation encountered socially produced more errors than misinformation from a non-social source. This finding has implications both for applied (forensic) and theoretical understanding of eyewitness memory.

Memory conformity : Disentangling the steps toward influence during a discussion

When two people see the same event and discuss it, one person’s memory report can influence what the other person subsequently claims to remember. We refer to this asmemory conformity. In the present article, two factors underlying the memory conformity effect are investigated. First, are there any characteristics of the dialogue that predict memory conformity? Second, is memory conformity differentially affected when information is encountered that omits, adds to, or contradicts originally encoded items? Participants were tested in pairs. The two members of each pair encoded slightly different versions of complex scenes and discussed them prior to an individual free recall test. The discussions were audiotaped, transcribed, and analyzed. Our most striking finding was that the witness initiating the discussion was most likely to influence the other witness’s memory report. Furthermore, witnesses were most likely to be influenced when an additional (previously unseen) item of information was encountered in the discussion.

Age differences in accuracy and choosing in eyewitness identification and face recognition

Studies of aging and face recognition show age-related increases in false recognitions of new faces. To explore implications of this false alarm effect, we had young and senior adults perform (1) three eyewitness identification tasks, using both target present and target absent lineups, and (2) an old/new recognition task in which a study list of faces was followed by a test including old and new faces, along with conjunctions of old faces. Compared with the young, seniors had lower accuracy and higher choosing rates on the lineups, and they also falsely recognized more new faces on the recognition test. However, after screening for perceptual processing deficits, there was no age difference in false recognition of conjunctions, or in discriminating old faces from conjunctions. We conclude that the false alarm effect generalizes to lineup identification, but does not extend to conjunction faces. The findings are consistent with age-related deficits in recollection of context and relative age invariance in perceptual integrative processes underlying the experience of familiarity.

When Eyewitnesses Talk

When two people witness an event, they often discuss it. Because memory is not perfect, sometimes this discussion includes errors. One persons errors can become part of another persons account, and this proliferation of error can lead to miscarriages of justice. In this article, we describe the social and cognitive processes involved. Research shows how people combine information about their own memory with other peoples memories based on factors such as confidence, perceived expertise, and the social cost of disagreeing with other people. We describe the implications of this research for eyewitness testimony.

On the "general acceptance" of eyewitness testimony research.

In light of recent advances, this study updated a prior survey of eyewitness experts (S. M. Kassin, P. C. Ellsworth, & V. L. Smith, 1989). Sixty-four psychologists were asked about their courtroom experiences and opinions on 30 eyewitness phenomena. By an agreement rate of at least 80%, there was a strong consensus that the following phenomena are sufficiently reliable to present in court: the wording of questions, lineup instructions, confidence malleability, mug-shot-induced bias, postevent information, child witness suggestibility, attitudes and expectations, hypnotic suggestibility, alcoholic intoxication, the crossrace bias, weapon focus, the accuracy-confidence correlation, the forgetting curve, exposure time, presentation format, and unconscious transference. Results also indicate that these experts set high standards before agreeing to testify. Despite limitations, these results should help to shape expert testimony so that it more accurately represents opinions in the scientific community.

Exposure duration: effects on eyewitness accuracy and confidence

The current study examined the relationship between the length of exposure to a face in an eyewitness setting and identification accuracy and confidence. A sample of 164 young (ages 17-25) and older (ages 59-81) adults viewed a simulated crime in which they saw the culprits face for a short (12 s) or long (45 s) duration. They were then tested with a target absent (a line-up not containing the culprit) or target present line-up. Identification accuracy rates for both young and older participants were significantly higher under the long exposure condition. In the short exposure condition, witnesses who had made a correct identification of the target were more confident than incorrect witnesses. In the long exposure condition the confidence ratings of accurate and inaccurate witnesses did not differ. Discussion focuses on the extent to which extended exposure may inflate confidence judgments and variables that may moderate the relationship between exposure duration and face recognition accuracy.