A Signal-Detection Analysis of Eyewitness Identification Across the Adult Lifespan
Middle-aged and older adults are frequently victims and witnesses of crime, but knowledge of how identification performance changes over the adult life span is sparse. The authors asked young (18–30 years), middle-aged (31–59 years), and older (60–95 years) adults (N = 2,670) to watch a video of a mock crime and to attempt to identify the culprit from a fair lineup (in which all of the lineup members matched the appearance of the suspect) or an unfair lineup (in which the suspect stood out). They also asked subjects to provide confidence ratings for their identification decisions. To examine identification performance, the authors used a standard response-type analysis, receiver operating characteristic analysis, and signal-detection process modeling. The results revealed that, in fair lineups, aging was associated with a genuine decline in recognition ability—discriminability—and not an increased willingness to choose. Perhaps most strikingly, middle-aged and older adults were generally effective at regulating their confidence judgments to reflect the likely accuracy of their suspect identification decisions. Model-fitting confirmed that the older adults spread their decision criteria such that identifications made with high confidence were likely to be highly accurate, despite the substantial decline in discriminability with age. In unfair lineups, ability to discriminate between innocent and guilty suspects was poor in all age groups. The research enhances theoretical understanding of the ways in which identification behavior changes with age, and has important practical implications for how legal decision-makers should interpret identifications made by middle-aged and older eyewitnesses.