Eyewitness Identification: Psychological Aspects

Throughout the eyewitness identification literature there has been a great deal of interest in the issue of eyewitness confidence. Research has shown that the confidence of an eyewitness is the principal determinant of whether or not jurors will believe that an eyewitness made an accurate identification (Lindsay, Wells, and, Rumpel). Early research suggested that there was no relation between the confidence with which eyewitnesses made identifications and the accuracy of those identifications. Later research has shown that there is a relation between eyewitness identification confidence and accuracy, although it is not a strong relation (Sporer, Penrod, Read, and Cutler). Under very favorable conditions (e.g., a good view, a fair lineup), the correlation between confidence and accuracy is probably somewhere around .40. For purposes of comparison, consider that the correlation between a person's height and a person's gender is .71. This means that confidence is a poorer predictor of accuracy than height is a predictor of gender. Importantly, research also shows that current procedures by law enforcement are probably harming the already-modest relation between eyewitness identification confidence and accuracy. Specifically, eyewitnesses are commonly given confirming feedback after they identify a suspect. This feedback takes many forms, such as "Good, that's the guy we thought it was" or "You got him!" Research shows that feedback of this sort to eyewitnesses who are in fact mistaken leads the eyewitnesses to recall that they were highly confident at the time of the identification (Wells and Bradfield). This confidence inflation effect is stronger for eyewitnesses who were in fact mistaken than for eyewitnesses who identified the actual perpetrator, leading to a diminution of the confidence-accuracy relation. This feedback problem is another factor leading eyewitness researchers to strongly advocate double-blind testing with lineups. Repeated questioning of eyewitnesses tends to have similar confidence-inflating properties such that eyewitnesses tend to become more confident in their incorrect reports with repeated questioning (Shaw and McClure).