POST-DICTING EYEWITNESS ACCURACY - CONFIDENCE, DECISION-TIMES AND PERSON DESCRIPTIONS OF CHOOSERS AND NON-CHOOSERS

This study sought to investigate the utility of several variables to post-dict eyewitness identification accuracy in target-present and target-absent line-ups in a staged-event paradigm. The incident involved and altercation between an experimenter and a confederate who attempted to take away the slide projector needed for an ongoing laboratory experiment. Sixty-two subject-witnesses were called back to the laboratory one week after the incident, purportedly to answer some additional questions about the laboratory experiment. They were asked to provide a description of the intruder and to indicate whether or not they though they would be able to identify the target (pre-decision confidence). Next, they saw a video line-up with or without the target present. Using choice of a line-up member as a mediating variable, with choosers post-decision confidence (r = 0.58) and decision-time (r = -0.43) were strongly related to the accuracy of this choice while pre-decision confidence was not. For non-choosers, no meaningful relationship between these variables and identification accuracy was observed. There was also some evidence that the number of descriptors was significantly related to identification accuracy (r = 0.28). Results are discussed in terms of the importance of choice as a mediating variable for post-dicting identification decisions in studies using both target-present and target-absent line-ups. Forensic implications of confidence and decision-time as verbal and non-verbal indicators for the post-hoc assessment of identification accuracy are stressed.