CrimeOne and Done: Experts Urge Testing Eyewitness Memory Only Once

Published 9 November 2021

If a witness was confident the very first time their memory was tested, there’s too high a chance that a contaminated, it is likely that their identification is correct. But if they are not confident the first time their memory was tested, there’s too high a chance that a contaminated memory will convict an innocent person. Experts say that in order to prevent wrongful convictions, only the first identification of a suspect should be considered.

We all know the scene from countless courtroom dramas: A witness points at the defendant and confidently declares to judge and jury: “That’s the one, that’s who did it!” But is it? Perhaps. If that same witness was also confident the very first time their memory was tested – write a team of psychological scientists and criminologists led by memory expert John Wixted of the University of California San Diego. Otherwise, there’s too high a chance that a contaminated memory will convict an innocent person.

As most of us also know, people have been convicted of crimes they didn’t commit on the basis of eyewitness memory. Some of these wrongful convictions have later been overturned by DNA or other physical evidence. But that type of evidence doesn’t always exist. To reduce the likelihood of injustice, the researchers suggest a simple, no-cost reform to our system of jurisprudence. “Test a witness’s memory of a suspect only once,” the researchers urge in a paper published by Psychological Science in the Public Interest, a journal of the Association for Psychological Science.

“The first test is the most reliable test,” says Wixted, a professor of psychology at UC San Diego, who has been working on memory for more than 30 years and eyewitness memory specifically for the past decade. “The first test probes the witness’s memory but also unavoidably contaminates the witness’s memory. All tests beyond that very first one only serve to test contaminated memory and to contaminate it further. And once a memory is contaminated, there is no way to decontaminate it.”

In their paper, Wixted and his co-authors – Gary Wells of Iowa State University, Elizabeth Loftus of UC Irvine and Brandon Garrett of the Duke University School of Law – explain how many wrongful convictions of innocent prisoners in which a witness conclusively identified the defendant in court began with something other than a conclusive initial eyewitness identification.