That scenario plays out more often than most people realize, and sometimes innocent people are convicted and sent to prison, as evidenced by the string of DNA-based exonerations in Dallas.
The Texas Legislature may have declined to improve police lineup procedures this year, but the Dallas Police Department and Dallas County DA Craig Watkins are moving forward as part of a national study to identify best practices. Though historically eyewitness testimony has been given the status of a courtroom gold standard, "photo lineup methods vary from agency to agency, and more and more research continues to cast doubt on the accuracy of eyewitness testimony," the Dallas News reported this week. ("Lineups by police get long look," Sept. 26)
The decision to participate in the study, reported the News, sprang from Dallas' recent string of wrongful convictions overturned. Said the News:
Surely, one would think, even the most ruthless "tuff on crime" maven wants the right person punished, and faulty lineup procedures invite such mistakes. The News has a good description of problems identified with traditional police photo lineups:
there's a consistent culprit in the bad cases, which date back to 1981. Notoriously unreliable eyewitness testimony was relied on in at least 11 of them.
Now the Dallas Police Department is joining the national debate among law enforcement agencies, academic institutions and state legislatures over the best way for police to conduct photo lineups. Dallas plans to be one of several cities taking part in a study that seeks to come up with the best possible way to confirm eyewitness identifications.
The $300,000 federally funded study will be led by the Washington-based Urban Institute beginning in January. Officials have also been in discussions with Los Angeles and Washington, D.C., as well as other cities, about participating in the study.
Kudos to folks in Dallas for agreeing to participate in the study, and let's hope by the time the 81st Texas Legislature rolls around in 2009 Texas can get past the debate over whether to change and move forward with best practices that prevent more convictions of innocent people.
Most law enforcement agencies, including Dallas police, have in recent years favored a traditional method in which six photos are shown simultaneously to the victim or witness by an investigator who knows the identity of the suspected guilty party.
But many psychologists consider the traditional method to be similar to conducting a multiple choice test where "none of the above doesn't seem like a possible answer," said James Doyle, director of the Center for Modern Forensic Practice at the John Jay College of Criminal Justice in New York.
"What the psychologists believe is happening is that witnesses will pick out the person who looks most like the perpetrator by comparing the people in the array to each other," Mr. Doyle said.
By knowing the identity of the potential suspect, the administrator may also be giving off cues – likely inadvertently – to the victim or witness while conducting the lineup, he said.
Academic research now tends to favor an approach called sequential double-blind, in which photos are shown one at a time by an administrator who doesn't know who the suspect is.
Showing pictures one at a time provides more accurate results, Mr. Doyle said, because the method is akin to giving a true-false test.
"They have to compare that picture with their memory of the crime," he said "They can't compare the pictures with each other."
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UPDATE: The Eyewitness ID Blog says the Dallas study's methodology sounds suspect.