Some of the well-settled best practices recommended in the Policy Review include:
The careful documentation of the identification, which decreases possible manipulation of witness certainty. Often, a witness’s initial confidence in an identification is rather low and provisional, but reinforcing statements and behaviors from authorities can exaggerate that certainty — sometimes greatly — by the time the witness testifies at trial. Documenting a witness’s “certainty statement” prior to any such feedback helps the jury to assess the eyewitness evidence appropriately.
Here’s a question: if police fail to document an eyewitness identification procedure, why should the results of the mystery procedure be admissible in court? Courts don’t let in DNA test results without procedural records, and the same standard should apply to eyewitness evidence collected by way of police procedures. New Jersey’s high court agrees — in State v. Delgado, it exercised its supervisory authority under the NJ constitution to require detailed records of an ID procedure as a prerequisite to admissibility, “to enhance the reliability of the factfinding process in [its] courts.” Delgado, 902 A.2d 888 (N.J. 2006).
The use of cautionary instructions. Prior to presenting the lineup members, the eyewitness should be instructed that the perpetrator may or may not be included in the lineup. Cautionary instructions remove some of the pressure on the eyewitness to choose a suspect when the culprit may not be in the lineup.
According to a meta-analysis of available psychological research, cautioning witnesses with this simple instruction prior to an ID procedure reduces misidentifications by 41.6% in lineups in which the real culprit isn’t present. Connecticut’s high court used its supervisory authority to require this procedural safeguard, in State v. Ledbetter (PDF). New Jersey followed that decision in State v. King earlier this year, as reported here. Other courts would be well-advised to follow suit.
The effective use of fillers. Fillers, or non-suspect individuals presented to an eyewitness as part of a lineup, if chosen correctly, allow authorities to judge the reliability of an eyewitness. The effective use of fillers is critical to ensuring that an innocent individual is not identified simply because of the composition of the lineup.
Using fillers in a manner that doesn’t make the suspect stand out seems like a no-brainer, yet we still have cases like Antonio Beaver, exonerated just last week after over 10 years in prison, who was wrongfully convicted based on a faulty eyewitness identification procedure in which he was the only member of the lineup with abnormal teeth, where the witness described the culprit as having a “David Letterman-like gap.” Mr. Beaver didn’t commit the crime, but he stood out in the lineup as the only one with abnormal teeth, a trait he just happened to share with the real culprit. A poorly designed lineup and the force of one eyewitness’s testimony landed him a prison sentence of 18 years, over 10 of which he served before DNA testing exonerated him. A simple procedural safeguard could have prevented this inexcusable injustice, and unfortunately Mr. Beaver’s case is not unique.
The use of an administrator who does not know which person is the suspect. Also called “double blind,” this procedure prevents well-intentioned officials from giving inadvertent clues to the witness as to which person in the lineup is the police suspect.
Every scientific experiment involving human subjects is conducted in double-blind format for a reason: when humans know the desired outcome, they tend to betray that knowledge, just like Oskar Pfungst and his dutiful horse, Clever Hans, the “counting” horse. Eyewitnesses respond to human cues just like horses do, and just as Clever Hans lost his ability to count when Dr. Pfungst was concealed behind a wall, so will the likelihood that eyewitnesses will incorrectly identity a police suspect when the lineup administrator doesn’t know the identity of that suspect.
The presentation of the lineup members “sequentially” (one at a time) rather than all at once. This procedure enhances accuracy by reducing the tendency for “comparison shopping” in favor of a more direct assessment of whether the lineup members match the witness’s memory of the perpetrator. It also takes pressure off the witness to choose a suspect even though the attacker might not be in the lineup.
It is worth noting that the Innocence Project and other advocates endorse the sequential lineup methodology only when it is coupled with a blind administrator. Otherwise, the Clever Hans risk becomes even more pronounced, when cues from the lineup administrator can only be interpreted as being directed at the single person being observed by the witness at a given time.
Lots of recurring themes in the Justice Project’s review, but maybe if they’re repeatedly frequently enough, more law enforcement agencies, courts, and policymakers will begin to take heed. The full report is here (PDF).