When well-meaning eyewitnesses testify in court that a defendant brutally attacked them or that they witnessed a defendant commit a violent crime, jurors are likely to believe them. That is because the vast majority of eyewitnesses to crimes are honest people who want to help solve crimes. Unfortunately, studies of wrongful conviction cases and of the fallibility of human memory have proven that eyewitnesses frequently are mistaken. In the first 82 DNA exonerations, mistaken eyewitness identifications were a factor in more than 70% of the cases, making it the number one cause of wrongful convictions in DNA cases.

It may seem strange that a rape victim, for example, could misidentify her rapist, but studies have shown that human memory can be easily – and unintentionally – manipulated during the investigative process. Through no fault of their own, eyewitnesses frequently participate in identification procedures that are likely to cause errors. Some examples of such procedures include: viewing photographic lineups or in-person lineups in which the suspect very obviously stands out from the “fillers"; participating in multiple lineups in which the defendant is the only person who appears in all of them; and receiving unintentional feedback – such as a pat on the back – from the police officer administering the case after identifying the suspect.

Although the problems inherent in eyewitness testimony might seem impossible to overcome, social science research has proven that there are several easy and inexpensive ways to improve the accuracy of eyewitness identifications. Some of those remedies include:

• Law enforcement personnel should use multiple-person lineups and multiple-person photo arrays whenever practicable.
• Identification procedures should include six to eight participants, including the suspect.
• Lineup participants should be selected to ensure a consistent appearance between suspects and the other participants so that suspects do not stand out.
• Only a single witness should participate in an identification procedure at one time.
• Law enforcement personnel should instruct each witness that the person who committed the crime may or may not be included in the lineup or photo array, and that the witness should not feel obligated to make an identification unless the witness recognizes the perpetrator.
• Each witness should be instructed that it is just as important to clear an innocent person of wrongdoing as it is to identify the perpetrator.
• Law enforcement officials conducting identification procedures should not know the identity of the actual suspects, in order to reduce unintended influence on the witnesses during identification procedures.
• Law enforcement personnel should show witnesses photos or suspects one at a time, rather than all at once, to reduce the likelihood that the witness will pick the person who looks most like the perpetrator.
• Law enforcement officials should find how confident a witness is about the identification as soon as the identification is made, because witnesses become more confident in their identifications as they continue participating in the investigative process.
• Law enforcement personnel should videotape or at least audiotape identification procedures, including conversations between the witness and police immediately prior to commencement of the identification procedure.
• Courts should permit, in appropriate cases, the introduction of expert testimony on the issue of human memory as it relates to the identification process and on the issue of best practices for eyewitness identification procedures.

For more information about the problems of witness identification and recommended solutions, you can visit these resources:

• Professor Gary Wells’ Website
• Eyewitness Evidence: A Guide for Law Enforcement (1999)
• Gary L. Wells, Mark Small, Steven Penrod, Roy S. Malpass, Solomon Ml Fulero, and C.A.E. Brimacombe, Eyewitness Identification Procedures: Recommenations for Lineups and Photospreads, Law and Human Behavior, Vol. 22, No. 6 (1998).
• New Jersey Eyewitness ID Protocols