Providing witnesses with an option to say 'I’m not sure' to a showup neither improves classification performance nor the reliability of suspect identifications

Objective: Past research with one-person showup identification procedures suggests that providing witnesses with an explicit option to opt-out reduces innocent-suspect identifications without reducing culprit identifications (Weber & Perfect, 2012). This finding suggests that improving performance from identification procedures might be as simple as providing witnesses with the option to opt-out from deciding. We examined whether providing witnesses with an option to say "not sure" improved performance from showup procedures. Hypotheses: We predicted that participants would opt-out more when given a poor view. We also predicted that classification performance would be better for those who had option to opt-out, and this improvement would be more pronounced for those who had a poor view. Finally, we predicted that the opt-out option would reduce more low-confidence than high-confidence decisions. Method: We randomly assigned Amazon Mechanical Turk Workers (Experiment 1A: N = 2,003, average age = 36.90 [SD = 11.67], 57.86% female) and university students (Experiment 1B: N = 721, average age = 19.91 (SD = 3.99), 69.72% female) to a 2 (culprit: present, absent) × 2 (memory strength: strong, weak) × 2 (not sure option: yes, no) between-participants design. We manipulated memory strength by giving witnesses either a clear or degraded view of the encoding video. After watching the encoding video, participants completed a 10-min filler task and were then presented with a showup procedure. Results: Participants who were given a poor view were more likely to opt-out than were participants who were given a clear view. Participants who were given the option to respond not sure reported higher confidence in their decisions. However, the not sure option did not improve classification performance. Conclusion: Contrary to our prediction, we found no evidence that an opt-out option improves performance from a showup procedure, which is consistent with past research examining opt-out options with lineup procedures. (PsycInfo Database Record (c) 2021 APA, all rights reserved).