Our lying eyes: eyewitness testimony is one of the least reliable types of evidence

Thomas Webb III still doesn’t like to discuss the horrors he experienced behind the bars of an Oklahoma prison. Sentenced to 60 years for rape in 1983, he arrived to prison at the bottom of the food chain.

The victim – then a 20-year-old student at the University of Oklahoma – had been certain Webb was the man who broke into her home and attacked her. She gave powerful, stirring testimony against Webb at his 1983 trial.

More than 30 years later, the two met in a high school auditorium. Webb had since been proven innocent by DNA and released after serving 13 years. It was a tragic case of mistaken identity.

“Thomas, I’ve been waiting so long to say this: I’m so sorry,” she told Webb. “I’m so, so sorry.”

“It’s OK,” he responded. “I forgive you. I forgave you a long time ago.”

In Webb’s case, the victim’s testimony proved so persuasive that not even Webb’s own public defender had believed he was innocent and urged him to take a plea deal. The only other evidence in Webb’s case had been an unreliable analysis of hair found at the scene.

Our Misplaced Faith

Eyewitness testimony has long held a sacred position in our Justice System. In a 1981 opinion, Supreme Court Justice William Brennan remarked, “There is almost nothing more convincing than a live human being who takes the stand, points a finger at the defendant, and says ‘That’s the one!’”

It turns out, however, that eyewitness identification is one of the least reliable types of evidence. More than two out of three erroneous and wrongful convictions are believed to be attributable to eyewitness misidentifications.

How Can Eyewitness Identifications be Wrong?

A major problem is that courts and juries assume eyewitness testimony is unassailable. What better evidence could there be than what you see with your own eyes?

The problem goes to a fundamental assumption that people have about memory - that a memory is like a file on a hard drive. That it gets recalled with perfect accuracy or not at all. In fact, the opposite is true. Memory is malleable and highly prone to error.

In 2015, Harvard published a study that chronicled the memories of a group of people about the September 11th attacks immediately after the attacks and at 11, 25, and 119 months after the attacks. They also recorded how confident people were that their memory was correct. What they found was that, while confidence remained high, the accuracy of the memories was highly inconsistent, particularly between the first survey (immediately after the event) and second survey (11 months after the event).

The findings suggest that our memory isn’t as reliable as we think, particularly when related to traumatic events. The same issues apply to eyewitness identification.

Why does this happen?

• When being asked to recall a memory, your mind seizes on the person in a lineup who bears the closest resemblance to what you recall, not necessarily the actual perpetrator
• Public and police expectations of eyewitnesses don’t leave room for two or more people in a lineup to resemble what you recall
• Two eyewitnesses can identity someone with an equal amount of expressed certainty, even though you might have a stronger ability to recall memories than another witness

In a new study, researchers hope achievements in psychology and our understanding of how human beings make decisions can protect innocent people from being locked away for years or even decades.

“Criminal justice reform is an uphill battle, partly because there are many concepts and methods that are deeply embedded in the culture of those who work in our legal and law enforcement systems,” said Thomas Albright, a co-author of the study and member of the National Academy of Sciences. “There are compelling principles of fairness at stake here, and science is a largely unmined source of new ideas to mitigate injustice.”