Post-identification feedback to eyewitnesses impairs evaluators' abilities to discriminate between accurate and mistaken testimony

Giving confirming feedback to mistaken eyewitnesses has robust distorting effects on their retrospective judgments (e.g., how certain they were, their view, etc.). Does feedback harm evaluators' abilities to discriminate between accurate and mistaken identification testimony? Participant-witnesses to a simulated crime made accurate or mistaken identifications from a lineup and then received confirming feedback or no feedback. Each then gave videotaped testimony about their identification, and a new sample of participant-evaluators judged the accuracy and credibility of the testimonies. Among witnesses who were not given feedback, evaluators were significantly more likely to believe the testimony of accurate eyewitnesses than they were to believe the testimony of mistaken eyewitnesses, indicating significant discrimination. Among witnesses who were given confirming feedback, however, evaluators believed accurate and mistaken witnesses at nearly identical rates, indicating no ability to discriminate. Moreover, there was no evidence of overbelief in the absence of feedback whereas there was significant overbelief in the confirming feedback conditions. Results demonstrate that a simple comment following a witness' identification decision ("Good job, you got the suspect") can undermine fact-finders' abilities to discern whether the witness made an accurate or a mistaken identification.