How Memory Effects Eyewitness Testimony

As our understanding of memory improves, new techniques to enhance their accuracy are making it possible for prosecutors to get reliable accounts of crimes from eyewitnesses.

Memory operates in stages and is affected by both system and estimator variables. “System variables” are those factors that the criminal justice system can influence, typically involving the actions of police (e.g., feedback and methods of eliciting the initial identification). “Estimator variables” are those factors that inherent in the event, such as the environmental conditions at the time and the characteristics of the witness and the perpetrator over which the criminal justice system has no control but that may have a substantial effect on the reliability of the identification.  

The scientific research on memory and eyewitness identification has both grown and matured over the past thirty years; there is now general scientific consensus on many areas affecting eyewitness identification, consensus that requires a change in the way courts, counsel, and police deal with the evidence. Scientists generally agree that “memory does not operate like a videotape” but rather is a “constructive, dynamic, and selective process.”

If memory errors  only affected our personal past, that would be bad enough. But the problems created by our lack in memory recollections affect all of society.  More than 75,000 prosecutions every year are based entirely on the recollections of others. While perjury is a felony, the overwhelming majority of eyewitness errors are not intentional mistakes.   However, they are the inevitable side effects of the remembering process.

In recent years, neuroscientists have documented how these mistakes happen. It turns out that the act of brining the past to the surface actually changes the memory itself. Although we have long imagined our memories as a stable form of information, a data file directly into the circuits of the brain, that persistence is an illusion. In reality, our recollections are always being altered, the details of the past warped by our present feelings and knowledge. The more you remember an event, the less reliable that memory becomes. This takes us back to the problem of eyewitness testimony. Eyewitnesses are repeatedly asked to recall what they saw, but their answers are inevitably influenced by the questions being asked.

Such errors often have tragic or irreversible consequences. According to the Innocence Project, a legal advocacy group, about 75% of false convictions that are later overturned are based on faulty eyewitness testimony.  Can anything be done to improve the situation? In a new paper by Neil Brewer, a psychologist at Flinders University in Australia, the answer is a resounding yes. Dr. Brewer focused on the police lineup, in which witnesses are asked to pick out a suspect from a collection of similar looking individuals.

Generally, witnesses are encouraged to take their time and carefully consider each possible suspect. But Dr. Brewer states, “that strong memory traces are easier to access than weak and mistaken ones, which is why he only gave his witnesses two seconds to make up their minds.” During his study he asked each witness to estimate how confident they were about the suspects they identified, rather than insisting on a simple yes-no answer.

To test this procedure, Dr. Brewer and his colleagues asked 905 volunteers to watch a series of short films showing such crimes as shoplifting and car theft. The subjects then looked at 12 portraits, only one of which was the actual suspect. According to Dr. Brewer’s data, his version of the lineup led to a large boost in accuracy, with improvements in eyewitness performance ranging from 21% to 66%. Even when subjects were quizzed a week later, those who were forced to choose quickly remained far more trustworthy.

The issue is that, when it comes to human memory, more deliberation is often dangerous. Instead of simply assessing our familiarity with a suspect’s face, we begin searching for clues and guidance. Sometimes this involves picking the person who looks the most suspicious, even if we’ve never seen him before, or being swayed by the subtle hints of police officers and lawyers. As a result, we talk ourselves into having a memory that doesn’t actually exist.

Fact, we can send a man to the moon, right?  So, prosecutors can work closer with memory experts and nail down the most accurate way to extract a point in time memory recall from an eyewitness.  Prosecutors can make simple enhancements to the criminal judicial system for a more reliable outcome from eyewitness testimony.   Unless we are ruthlessly skeptical of the past, we will continue to confuse fact and fiction, and innocent will be sent to jail.

    Work Cited

“Eyewitness Misidentification.” – The Innocence Project. N.p., n.d. Web. 09 Mar. 2015. “Eyewitness Misidentification“

Dorf, Michael C. “FindLaw Legal Commentary.” FindLaw’s Writ. N.p., Wed May 2001. Web. 28 Feb. 2015. “Find Legall Law Commentary”

Hartnett, Kevin. “How to Make Eyewitness Evidence More Reliable – The Boston Globe.” BostonGlobe.com. N.p., 27 Feb. 2015. Web. 28 Feb. 2015. “How To Make Eyewtiness Testimony More Reliable”

“Memory.” Wikipedia. Wikimedia Foundation, n.d. Web. 27 Feb. 2015. “Memory”

“How To Improve Eyewitness Testimony | WIRED.” Wired.com. Conde Nast Digital, n.d. Web. 24 Mar. 2015. “How To Improve Eyewitness Testimony”