A team of scientists from USC and other Southern California research institutions has developed a unique way to measure the reliability of an eyewitness trying to pick a culprit from a police lineup, it was announced Tuesday.
The new forensic approach attempts to gauge the strength of witness memory while minimizing the influence of unwitting bias in an effort to explain -- and solve -- why so many innocent people get convicted of crimes. The method challenges police lineup techniques that have been entrenched for nearly a century, the researchers said.
"Our new lineup method uncovers the structure of eyewitness memory, removes decision bias from the identification process and quantifies the performance of individual witnesses,'' said Sergei Gepshtein, an expert in perceptual psychology and neuroscience at the USC School of Cinematic Arts and a corresponding author of the study.
"This study is a great example of using laboratory science to bring about criminal justice reform," he said.
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Gepshtein and collaborators from the University of California and the Salk Institute for Biological Studies in La Jolla, where he is also a member of the Center for the Neurobiology of Vision, conducted the study, which was published Tuesday in the journal Nature Communications.
At its core, the new method accounts for mistakes in witness decision making, scores a witness' responses based on paired comparisons of photos instead of a traditional lineup and assigns a probability value to the testimony. Among the advantages, the technique minimizes biases that confound memory and inserts elements of the scientific method into eyewitness testimony, Gepshtein said.
"What's at stake is the confidence people have in their criminal justice system. People want the criminal justice system to use the best methods available for prosecuting crime," he said.