Confidence in Identifications

The confidence that eyewitnesses express in their decision at an identification test or lineup has long been recognized within the criminal justice system as an indicator of the likely reliability or accuracy of the witness. In contrast, psychology researchers have downplayed the diagnostic value of eyewitness identification confidence. Although only a relatively small proportion of the variance in identification accuracy is associated with variance in confidence, recent research using what is known as a confidence-accuracy (CA) calibration procedure suggests that confidence—measured immediately after the identification decision—can provide a useful (but not infallible) pointer for crime investigators to the likely accuracy of positive but not negative (i.e., lineup rejections) lineup decisions. This conclusion definitely does not apply, however, to confidence judgments expressed in the courtroom as, by this time, there has been an opportunity for postidentification influences (such as feedback from lineup administrators or other witnesses) to shape any subsequent confidence judgments. Nor is the conclusion applicable to judgments expressed by witnesses prior to having viewed a lineup. A major challenge for future research in this area will be to define the boundary conditions for obtaining robust CA calibration, which, in turn, will enhance the capacity to diagnose the likely accuracy of identification decisions.

Eyewitnesses will often provide some sort of expression of confidence in their memory when they examine a police lineup or photo spread or when they testify in court about the identity of the offender. Their degree of confidence is known to exert a strong influence on assessments made by the police, lawyers, and jurors about the likely reliability of their testimony. Yet it is known that eyewitness confidence is sometimes an extremely misleading cue to the likely accuracy of an identification. The following sections examine when identification confidence is informative about the offender's identity and when it is likely to mislead.

Eyewitness confidence has been of major interest because confidence is an easily obtainable index that could potentially provide a guide for the criminal justice sector as to the likely reliability of an eyewitness identification response. Given the crucial role that identifications can play in some investigations and trials, together with the overwhelming evidence of eyewitness fallibility provided by DNA exoneration cases and experimental simulations of identification tests, knowing how much weight should be attached to witnesses' confidence estimates is an important forensic issue.

Even prior to attending an identification test, witnesses may express a particular degree of confidence in their capacity to identify the offender, with the confident witness likely to impress police investigators. These assessments are likely to be influenced by a variety of factors such as witnesses' evaluations of the strength of the memorial image for the offender, their recollections of the quality of view they had of the offender at the time of the crime, their perceptions of how good a recall they displayed when interviewed by the police, and so on. To date, there is no evidence to indicate that such preidentification test confidence assessments should be considered as a guide to the likely accuracy of an identification.

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