How Accurate Is Memory? How Accurate Is Eyewitness Testimony?

Oct 7, 2014

Psychology professor Steven Smith
Credit Courtesy of Steven Smith

As people age, they become more aware of memory lapses.

“Memory loss is fairly universal, and as we start experiencing more memory loss, we become a lot more aware of it,” said Steven Smith, a Texas A&M University psychologist who is on sabbatical and is spending the semester at Washington University. “We become very defensive about it. We become very anxious about it. And that makes memory worse.”

In part, Smith said this happens because of changes in the brain after age 40. At that point, he said, the brain is through with the “good kind of development,” and has less capacity.

“As kids, we make a memory error — eh, big deal, I forgot so what?” he told “St. Louis on the Air” host Don Marsh. “But as an older adult, when you do that you think ‘Uh-oh, here goes. This is the sign. I’m going downhill.’ ”

There are times when memory is very important. Imagine, for example, seeing a stranger for less than a minute as he committed a robbery. On average and in good circumstances, Smith said the witness would accurately pick the suspect from a lineup about 70 percent of the time. Other details may be less accurate.

“Having a wrong memory doesn’t mean that you’re lying,” Smith said. “We have wrong memories all the time. False memory is just part of everyday experience.”

Smith has testified as an expert witness in criminal trials, and said eyewitness testimony is “better than a Ouija board or a psychic; it’s not as good as DNA evidence that has not been contaminated.”

It’s also easy to influence a memory, he said.

“Anyone is highly susceptible to inference, and if someone asks a question that implies an inference, we may later remember that inference as what really happened.”

In a trial situation, the witness is likely not remembering the event at all.

“By the time they get to the stand, they’re not remembering anything. They’re basically rehearsing what they’ve rehearsed before the case,” Smith said. “They know they’ve identified a person, let’s say in a photo spread, or that they’ve remembered events in a certain way. And they go over that and over that and over that in their mind. By the time they get up to the witness stand, generally speaking, they’re remembering having remembered it a hundred times already, rather than the original events.”

Improving Memory

To help improve memory Smith makes two simple suggestions: Be mindful and be organizes.

“Everyone has a limited amount of attention, and that’s why we talk about paying attention ’cause it costs something,” Smith said. “Paying attention will get you more recorded and help you, later on, remember things.”

The same is true of structure, such as keeping car keys in the same place every day, he said.

Good diet and exercise is important, but there are limits.

“I think that too many people think that they’re going to improve their memories by sticking something in their mouth or running laps or something like that,” Smith said. “Those don’t hurt, but they won’t really ensure a good memory. The less healthy you are, the lousier you’ll be at everything.”

“St. Louis on the Air” discusses issues and concerns facing the St. Louis area. The show is produced by Mary Edwards and Alex Heuer and hosted by veteran journalist Don Marsh. Follow us on Twitter: @STLonAir.