Can We Trust Eyewitness Testimony?

“Who are you going to believe, me, or your lying eyes?” Variations of this quote date back to Chico Marx in Duck Soup and earlier. Psychologist Elizabeth Loftus has testified in criminal trials that eyewitness testimony is not as trustworthy as it seems.

Loftus has shown that it is easy to implant false memories of events that never occurred. Her student Jim Coan developed the “Lost in the Mall Technique” and showed how people could be made to falsely believe they had been lost in a shopping mall as a child. People have been charged with serious crimes, based on testimony that turned out to be the result of such implanted false memories. The McMartin Preschool case was a notable example. Improper questioning of children seemed to create false memories that later were very real to them. So, it was quite a surprise to attend a talk by psychologist John Wixted of UC San Diego with the title “Eyewitness Memory is Reliable but the Criminal Justice System is Not,” here at the UCSB SAGE Center.

He started out explaining the importance of the work by Loftus. The Innocence Project has overturned 375 wrongful convictions. The leading factor in 72% of these cases? Eyewitness misidentification. It is a real problem. The memory of the actual perpetrator can be replaced by the memory of the innocent guy in the courtroom.

It starts with a police lineup, early in an investigation. The witness is shown a photo of the suspect surrounded by photos of “fillers.” This process may be repeated multiple times by the time the trial occurs months later. When considering whether eyewitness memory is reliable, we need to ask: “Which test are you talking about?”

Evidence can take many forms. It could be a fingerprint or DNA – or the memory of a face. Evidence of any kind may be incomplete. Or it may be contaminated – which is why crime scenes are cordoned off quickly. Suppose incomplete DNA is found on a gun. We could get a better match to the suspect if we had the suspect pick up the gun later – clearly not acceptable! Yet, we effectively do the same thing by contaminating witness memory.

The first test using a photo lineup changes (i.e. contaminates) the witness’s memory. It is how the face of an innocent suspect first gets into the brain of the eyewitness, so no later test can be fair to that suspect. Wixted says this is why we must only use the first test, and the results of that first lineup test, if properly conducted, are reliable.

Researchers like Gary Wells developed improved lineups over the years. He showed why there should be only one suspect in each lineup, why each filler should match the witness’s description of the suspect, and why the officer administering the test should be blind to which is the suspect. That is a properly conducted lineup. On an initial, properly conducted lineup, if a witness says they are quite certain about their identification, they are usually correct. But only on the first test – later tests are inherently contaminated!

No one had ever tested this in the real world until Wixted and colleagues conducted a field study with the Houston Police. If a witness says they are not sure, believe them! Perhaps more importantly, if they pick a filler out of the lineup or reject the lineup on the first try, that is evidence of innocence of the suspect.

Which brought Wixted to the case of Charles Don Flores. Witness Jill Bargainer described two perpetrators as both being thin, white men with shoulder length hair. A neighbor also said both were white. Suspect Richard Lynn Childs fit the description and was picked from the lineup and later convicted. But he had an accomplice, and the police suspected Flores, a known associate of Childs. On the first test, Bargainer understandably rejected the lineup containing a photo of Flores, a heavyset Hispanic man with short hair. But a year later at trial she picked Flores with 100% certainty. Flores was convicted and has been on death row 22 years with no further appeal possible.

If we followed the advice of Loftus, we might rule out all eyewitness testimony as untrustworthy. But Wixted is making a point that the first testimony is trustworthy if made with confidence. And if a witness picks a filler or says the suspect is not in the lineup, that is actual evidence of innocence. He is doing his best to raise awareness that Flores is probably innocent of this crime. It turns out that eyewitness testimony is not so special after all. Like other forms of evidence, it has value if it is not contaminated and properly tested.