AP: Dallas police pioneering new photo lineup approach

By JEFF CARLTON (AP) – 23 hours ago

DALLAS — Frustrated with a string of wrongful convictions, the Dallas police department is now the nation's largest force to use sequential blind photo lineups — a widely praised technique designed to reduce mistakes made by witnesses trying to identify suspects.

Dallas is not the first department to use the pioneering method. But experts hope that by using it in the county that leads the nation in exonerating wrongly convicted inmates, Dallas will inspire other departments to follow suit.

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The department switched to sequential blind lineups in April. Before that, Dallas police administered most lineups using the traditional six-pack — law-enforcement lingo for mounting six photos onto a folder and showing them to a witness or victim at the same time.

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An analysis of 26 recent studies shows that presenting mug shots sequentially instead of simultaneously produces fewer identifications but more accurate ones, Wells said. Overall, identification rates in sequential lineups are 15 percent lower than simultaneous lineups — but misidentification rates also drop by 39 percent, he said.

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Dallas police also ask witnesses to express how confident they are in their identifications, Pughes said. That's to avoid what Innocence Project Co-Director Barry Scheck calls a "forced-choice response" when police, intentionally or not, nudge a witness into expressing certainty.

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Nationally, more than 75 percent of DNA exonerees who have been released since 1989 were sent to prison based on witness misidentification, according to The Innocence Project, a New York legal center specializing in overturning wrongful convictions. It's the most common element in a wrongful conviction, the center said.

Since 2001, 21 people in Dallas County have had convictions overturned after DNA proved their innocence. A majority of them were in the city of Dallas.

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...with police and prosecutors actions, rather than witness misidentification.

serial photo lineups, specifically. the psychological evidence is clear that they are more reliable.

that's important

Does having a group of 6 photos imply you have to pick one of them, so you find the one that seems the most similar?

when you present a photo lineup (of either sort), you have to use language that says that the person who committed the crime may not be included in the pictures presented, and it;s just as important to eliminate the innocent from suspicion as to convict the guilty, etc.

however, there is an "impetus to please" to some extent, plus memory is malleable, etc.

if all 6 photos are sitting in front of you, to some extent, people may just try to look for the one that's "closest" and then convince themself that it was the same person, etc.

if you present the photos serially, such is less likely to happen. usually when you get to the actual suspect, the person will be like "oh, that's him. definitely". if that doesn't happen you go through all 6 and the person doesn't have the opportunity to try to fit their memory to the evidence presented.

and empirical evidence supports this theorizing. iow, studies have been done that prove (imo) that it does work this way.

the two issues you will have with lineups are 1) false positives and 2) not identifying positively the actual suspect

(1) is obviously more concerning (although there is a balancing equation), because our system of justice (to contrast with someothers) is that it is better to let 10 guilty men go free than convict one innocent man.