Research on factors that affect the accuracy of eyewitness identification procedures has given us an increasingly clear picture of how identifications are made, and more importantly, an improved understanding of the principled limits on vision and memory that can lead to failure of identification. Factors such as viewing conditions, duress, elevated emotions, and biases influence the visual perception experience. Perceptual experiences are stored by a system of memory that is highly malleable and continuously evolving, neither retaining nor divulging content in an informational vacuum. As such, the fidelity of our memories to actual events may be compromised by many factors at all stages of processing, from encoding to storage and retrieval. Unknown to the individual, memories are forgotten, reconstructed, updated, and distorted. Complicating the process further, policies governing law enforcement procedures for conducting and recording identifications are not standard, and policies and practices to address the issue of misidentification vary widely. These limitations can produce mistaken identifications with significant consequences.
The NAS report has endorsed several specific, science-based recommendations for law enforcement that are already in place in some jurisdictions about the way identification procedures should be conducted. Since witnesses often pick up inadvertent clues from the officer conducting a live or photo lineup, these procedures must be performed “blind” by an officer who is unaware of the identity of the suspect or who does not know the position of the suspect in the lineup. The witness should also be told that the perpetrator might or might not be present, and that the investigation will continue regardless of whether he or she identifies anyone.The researchers also recommend that police take a confidence statement. The witness should be asked to describe in his or her own words how confident he or she is in the identification at the time the identification is made. This is critical for helping jurors evaluate the reliability of the identification when the case goes to trial. Witnesses’ confidence is often falsely inflated by confirming feedback by the time they testify at trial. Indeed, researchers recommend that the lineup be electronically recorded so there is a permanent record of what occurred.