In police lineups, is the method the suspect?
CHICAGO AND BOSTON
A police lineup is often the moment of truth in a criminal investigation. It's also, say many experts, highly fallible.Skip to next paragraph
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Of the 175 convictions overturned by DNA evidence, 75 percent were convicted largely because of eyewitness testimony that turned out to be mistaken.
Those exonerations have energized efforts to reform the way police conduct lineups and get eyewitness identifications. A growing number of counties and states are adopting measures to improve accuracy and limit influences on witness memory.
Now, though, a first-of-its-kind study from Illinois is casting doubt on a reform called "sequential double-blind." That method shows witnesses photos of potential suspects one at a time, rather than all at once, and even the administrator doesn't know who the suspect is.
The study's results - which suggest the old method was both more accurate and more likely to produce an identification - are a boost to police departments that have resisted lineup changes. Others say the study was flawed, and they worry that it will be used as an excuse to halt all eyewitness-identification reforms. For now, supporters say more study - and more action - is needed, and they hope that a single study won't derail years of effort to improve what they say is a highly flawed system.
"My fear is that the debate over sequential blind will obscure everything, and you'll have police departments who are reluctant to change at all, or not adopt anything," says Barry Scheck, a professor at Yeshiva University's Cardozo School of Law in New York and co-director of the Innocence Project.
Eyewitness reliability is often a hot- button issue, especially in sexual assault cases. Just last week, it arose in the Duke University case in which a stripper has said she was raped by several lacrosse players. She picked two out of a photo lineup, but critics faulted the lineup for containing no fillers, only lacrosse players, likening it to a multiple choice test with no wrong answers.
The Illinois study focused only on the question whether to do sequential blind lineups, a switch that just a handful of jurisdictions have mandated so far. Commissions in North Carolina, Wisconsin, Virginia, and California have recommended that approach, and other jurisdictions are considering it. Many are reviewing the Illinois study closely.
The study took place in three districts: Chicago, Evanston, and Joliet. During the course of a year, police compared the number of times a witness picked out the suspect using the traditional method - in which photos were shown simultaneously, and the administrator might know which is the suspect - with the new one.
Until now, research has shown that the sequential method sets a higher bar for accuracy: the witness compares the photo or person to his memory, rather than to the others in the lineup. Using administrators who are "blind" minimizes the risk that they will convey conscious or unconscious approval once the witness makes his pick - an action that could solidify a formerly hazy memory.
It's a more conservative approach that results in fewer overall identifications, and has raised debate about whether it's better to get more guilty people off the street or avoid a false conviction. "It's a policy decision on how cautious we want our witnesses to be," says Gary Wells, a psychology professor at Iowa State University who has conducted more than 100 experiments on witness memory.
So researchers weren't surprised that sequential lineups in the Illinois pilot showed a lower rate of overall identifications: Witnesses made IDs in 53 percent of lineups, versus 62 percent for simultaneous ones.