Confidence in Identifications, Malleability

Eyewitnesses are often asked to indicate how confident they are in the accuracy of their identification and other testimony-relevant judgments. These reports are highly influential in evaluations of identification accuracy. Unfortunately, eyewitnesses' confidence reports are highly malleable, easily influenced by myriad variables. The solution is to record witnesses' confidence in their identification and report of crime details immediately, so as to preserve whatever useful information confidence provides.

A witness's confidence in the accuracy of his or her identification is perhaps the most studied of all variables related to eyewitness decision making—for good reason. Eyewitness confidence is the most intuitively appealing variable for use in assessments of accuracy. Indeed, it is specially highlighted by the U.S. Supreme Court for use in such evaluations. This recommendation is consistent with lay assumptions of what variables predict identification accuracy: People believe that a confident witness is an accurate one. This assumption does have empirical support. Under certain circumstances, there is a strong, positive correlation between confidence and accuracy. For example, when viewing conditions are disparate, a strong confidence-accuracy relationship emerges: Witnesses who see a culprit under difficult viewing conditions are less confident compared with those who see a culprit under optimal viewing conditions. Other research confirms the existence of a useful relationship between confidence and accuracy. One meta-analysis determined that the confidence-accuracy correlation for witnesses who made choices from lineups or photo spreads was moderate (r = .41). These investigations are highly valuable in clarifying the maximum possible utility of confidence reports in assessing accuracy.

These investigations capture confidence reports under the best possible circumstances. Because no external variables have been introduced (e.g., photospread administrator influence), they are, in some sense, pure measures of the extent to which confidence is related to accuracy. Therefore, it is possible to think of these confidence reports as the estimator versions of this variable because they derive from factors outside the control of the justice system. For example, the system cannot ensure that a witness has a good view of the culprit. Therefore, to the extent that the quality of the witness's view determines how confident he or she is, the justice system has no hand in a witness's confidence.

In other ways, the justice system has a substantial role in the level of confidence an eyewitness expresses in his or her identification. This influence is driven by [Page 143]system variables—those variables the justice system can control. Many system variables have been implicated in confidence inflation. This influence has been demonstrated across three different categories of confidence reports: current confidence in the identification decision (e.g., How confident are you in the accuracy of your identification right now?), retrospective confidence in the identification decision (e.g., How confident were you when you made your identification?), and reports about details of the witnessed event (e.g., What kind of disguise was the culprit wearing?). As described below, the malleability of confidence in each of these three categories can be attributed to system variables.