Over the past two decades, 305 people wrongfully convicted of crimes have been exonerated due to DNA evidence. The Innocence Project has helped exonerate 170 of those people, all of whom spent years or even decades in prison. About three-quarters of the wrongful convictions involved mistaken eyewitness testimony, according to lawyer Barry Scheck, who founded The Innocence Project in 1992.
"It's the single greatest cause of the conviction of the innocent," Scheck says.
Now, he and his colleagues are working with psychologists who study eyewitness identification to develop new judicial guidelines that incorporate what scientists have learned about fallible memories, and to improve police lineup procedures to minimize eyewitness error.
For example, researchers have learned that simply telling witnesses who are about to view a lineup that the true perpetrator might not be present reduces the rate of false identifications, while not affecting the rate of correct identifications. Another finding: It is important to get a statement from the witness at the time of the lineup about how confident they are in their identification, because confidence in mistaken identifications can increase over time. And another: Using a double-blind method in which the person presenting the lineup does not know which person is the suspect also reduces false identifications.
"That might seem obvious to scientists, but to law enforcement it can be a struggle" to accept, Scheck says.
Now, due to his and others' efforts, police departments around the country are beginning to adopt best practices like these. They have even been written into law in New Jersey and Ohio.
Meanwhile, Scheck and other attorneys are also relying on psychologists' research to convince courts to change the way they admit and evaluate eyewitness testimony. In 2011, for example, New Jersey's highest court decided in State v. Henderson to require state courts to give jurors information about factors that can lead to eyewitness mistakes. The ruling in this case also makes it easier for defendants to challenge the admissibility of eyewitness evidence when police don't follow proper procedures.
In his keynote address at APA's convention, Scheck will discuss the psychological research that led to these judicial changes, and what changes are yet to come.
"The courts are lagging indicators," he says. "It shouldn't take 30 years for [scientific] evidence to get adopted by the courts. It should change a little bit more rapidly."
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