Comparing witness performance in the field versus the lab: How real-world conditions affect eyewitness decision-making.

Objective: This field-simulation experiment was designed to compare eyewitness performance when conducting show ups and lineups under field versus laboratory conditions.
Hypotheses: We expected to replicate the findings from previous field-simulation experiments showing overconfidence in show up identifications made under field but not lab conditions, and further predicted that under field conditions, high-confidence identifications are more likely to be correct when using lineups compared with show ups. It was also expected that field conditions would lead witnesses to lower their criterion for choosing with show ups, but we did not know how field conditions would affect lineup decision-making.
Method: Participants (N = 719) witnessed the theft of a laptop computer and were asked to identify a suspect from a live show up, a photographic show up, or a photographic lineup administered under either field or lab conditions. In the field condition, uniformed officers functioned as experimenters and participants were immersed in what they were led to believe was an actual police investigation. In the lab condition, participants were debriefed before the identification procedure that the theft was staged for research purposes and that their identifications were being made as part of a study on eyewitness memory.
Results: As predicted, witnesses were overconfident in their show up identifications made under field but not lab conditions, and high-confidence identifications were more likely to be correct when using lineups compared with show ups. Also as expected, field conditions led witnesses to lower their criterion for choosing with show ups regardless of culprit presence. However, the opposite was true for lineups, such that field conditions resulted in witnesses raising their criterion for choosing.
Conclusions: Field conditions had a very different effect on witness performance when conducting show ups compared with lineups. When witnesses were led to believe that their identification would result in the arrest and prosecution of the suspect, they became more liberal in their decision-making when show ups were used but more conservative when lineups were employed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).