Last month the New Jersey Supreme Court mandated new procedures for handling eyewitness testimony to take into account the potential for mistaken identifications, which seem to occur about one-third of the time. The decision was based mainly on a report by former judge Geoffrey Gaulkin, the special master appointed to study the issue. While the court endorsed most of Gaulkin's recommendations, it did not take a position on the relative merits of presenting photos to eyewitnesses sequentially instead of simultaneously. Research suggests that simultaneous presentation encourages witnesses to use "relative judgment," picking the person who most closely resembles the perpetrator, which can result in erroneous identifications. Such mistakes are less common when witnesses see the pictures one after another, but critics of sequential presentation worry that the method also reduces correct identifications. A recent study suggests that concern is misplaced:
The new report, based on actual cases in the field, suggests that photographs presented one by one by a person not directly connected with a case significantly reduced identifications of fillers (people known not to be the suspect) from 18 percent in simultaneous lineups to 12 percent in sequential ones.
And while a 2006 study cited by opponents of the sequential technique suggested that witnesses make fewer selections over all in sequential lineups than in simultaneous ones, the new report showed that the sequential approach leads to just as many picks of suspects as do the simultaneous techniques if conducted as they commonly are in the field, with the witnesses getting an opportunity to view the images a second time if they request it.
Although the advantage for sequential presentation in the new study was relatively small, there does not seem to be any downside. Still, many police officials remain unconvinced. For example, the police chief in Austin, Texas, where much of the research for the new study was conducted, says he will continue to let officers choose between simultaneous and sequential presentation. Another reform, blind presentation of photographs by an officer not involved in the investigation, is more widely accepted, though by no means universally practiced.
I discussed the perils of eyewitness testimony in a column last month.