Eyewitness Identification and Testimony

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Eyewitness Identification and Testimony

SUMMARY

In the courtroom, eyewitness identification is one of the most damning types of evidence. When an eyewitness identifies a perpetrator of a crime, jurors often stop hearing other evidence. This is especially true when the witness is an innocent bystander to a crime. After all, a jury member might think, What does the witness have to gain by misidentifying a perpetrator of a crime? However, a great deal of research has demonstrated the fallibility of eyewitness identification. An eyewitness’s ability to correctly identify a criminal depends mainly on his or her memory. The memory process has been broken down into three stages, and errors can occur at any one of them. In the first stage, the crime must be encoded. In the second stage, it has to be stored. In the third stage, it has to be retrieved. According to one study, in 74% of convictions, eyewitness testimony was the only evidence, and in nearly half of those cases there was only a single eyewitness. Erroneous eyewitness identifications are responsible for more wrongful convictions than is any other type of evidence. The Manson criteria specify five variables that should be considered when evaluating an individual’s eyewitness identification; (a) opportunity to view the criminal, (b) level of attention, (c) accuracy of a previous description, (d) degree of certainty, and (e) amount of time between the crime and identification. Most of these variables are difficult to estimate, and eyewitness certainty is unrelated to accuracy. Although the criminal justice system attempts to discover mistaken identifications through voir dire, cross-examination, and jury deliberation, these are not particularly effective in this regard.

The phenomenon of witnesses being more accurate in identifying people of their own race than people of other races is called the cross-race effect (or own-race bias). Research has shown that even people who are relatively low in prejudice still have trouble identifying persons of other races. The rate of false alarms (misidentifications) is much larger when the identification is made cross-racially, but the cross-rate effect appears to lessen with increased contact with other races. Contrary to popular belief, memory for stressful events is not enhanced. Memory for arousing events may seem vivid, but the details of such events are not remembered any better than are details of everyday events. But witnesses have been shown to have higher correct identifications in conditions of low stress than in conditions of high stress (71% vs. 38%).

Witnesses also show higher false positives in high-stress conditions than in low-stress conditions (58% vs. 25%), with this pattern holding, regardless of the type of identification procedure (live lineup, photo spread, or sequential photo). One explanation of this finding is that in highly stressful situations, especially those involving weapons, observers focus on the weapon rather than on the perpetrator. Witnesses are also likely to identify someone near the scene of the crime as the person who committed it, or tend to make an identification during the identification procedure (e.g., when viewing mug shots) through a process called unconscious transference. Suggestive comments and presumptive questions can also lead to mistaken recall. Sometimes, witnesses fill in missing pieces of information on the basis of their own scripts or their knowledge of how things usually happen (e.g., in a robbery there’s usually a gun). Although jurors often think a witness’s confidence is a good indicator of accuracy, data suggest otherwise. There are variables that are not controllable (estimator variables) such as time of day or race of perpetrator and variables that are controllable (system variables).

Scientific research has offered methods to reduce the system variables and improve eyewitness accuracy. Methods include using blind lineup administrators, providing unbiased instructions during a lineup, ensuring that lineups are less biased, asking witnesses to rate their confidence prior to viewing the lineup, allowing for video recording of identifications, using sequential rather than six-pack lineups, and allowing expert testimony to address the issue of eyewitness accuracy. Methods such as hypnosis have been shown to be ineffective at improving eyewitness memory, whereas the cognitive interview increases the number of relevant details recalled without increasing the amount of incorrect information. In the cognitive interview, the interviewer first develops a rapport with the witness and then suggests to him or her a number of memory retrieval techniques.