We’ve known for decades that eyewitness accounts of events are unreliable and that they generally become more unreliable over time. We’ve also long known that eyewitnesses are vulnerable to suggestion, particularly from authority figures. In short, social science and psychiatric studies have shown that our attention is fleeting, our recollection ephemeral and our memory malleable.

The video below is one of the more well-known examples of how easy it can be to miss key details of a scene while we’re distracted with other things. It’s a short test. If you haven’t already seen or read about it, you can take it right now before reading on.

Despite the fact that social science has been well aware of these problems for decades, eyewitness testimony is still considered particularly powerful in the courtroom. It is precisely because of these two characteristics of eyewitness evidence — that it flawed and subject to suggestion and that it nevertheless retains such power with juries — that the courts should go out of their way to make sure eyewitnesses have been properly vetted, and their testimony has been properly elicited.

The good news is that there are some simple procedures police and prosecutors can follow to vastly improve the integrity of eyewitness testimony. The bad news is that because these procedures result in fewer identifications, police and prosecutors have been reluctant to implement them. And the courts haven’t been all that interested in ensuring that they do. (Two exceptions are the state supreme courts in Oregon and New Jersey.) Most recently, the U.S. Supreme Court declined to rule that eyewitness identifications made under suggestive circumstances were a violation of a defendant’s due process rights. The vote was 8 to 1.

This week, a team of researchers at the National Academy of Sciences released a comprehensive report on eyewitness evidence. From the summary:

Research on factors that affect the accuracy of eyewitness identification procedures has given us an increasingly clear picture of how identifications are made, and more importantly, an improved understanding of the principled limits on vision and memory that can lead to failure of identification. Factors such as viewing conditions, duress, elevated emotions, and biases influence the visual perception experience. Perceptual experiences are stored by a system of memory that is highly malleable and continuously evolving, neither retaining nor divulging content in an informational vacuum. As such, the fidelity of our memories to actual events may be compromised by many factors at all stages of processing, from encoding to storage and retrieval. Unknown to the individual, memories are forgotten, reconstructed, updated, and distorted. Complicating the process further, policies governing law enforcement procedures for conducting and recording identifications are not standard, and policies and practices to address the issue of misidentification vary widely. These limitations can produce mistaken identifications with significant consequences.

Writing about the study in USA Today, Innocence Project co-founder Barry Scheck points out that 73 percent of the wrongful convictions so far overturned by DNA testing included false identification by eyewitnesses. More from Scheck:

The NAS report has endorsed several specific, science-based recommendations for law enforcement that are already in place in some jurisdictions about the way identification procedures should be conducted. Since witnesses often pick up inadvertent clues from the officer conducting a live or photo lineup, these procedures must be performed “blind” by an officer who is unaware of the identity of the suspect or who does not know the position of the suspect in the lineup. The witness should also be told that the perpetrator might or might not be present, and that the investigation will continue regardless of whether he or she identifies anyone.
The researchers also recommend that police take a confidence statement. The witness should be asked to describe in his or her own words how confident he or she is in the identification at the time the identification is made. This is critical for helping jurors evaluate the reliability of the identification when the case goes to trial. Witnesses’ confidence is often falsely inflated by confirming feedback by the time they testify at trial. Indeed, researchers recommend that the lineup be electronically recorded so there is a permanent record of what occurred.

Groups like Scheck leads have been making these recommendations for years now. Still, just 10 states now require them. Previous NAS studies on forensic specialties like bullet lead composition have made a pretty big splash. The studies helped overturn a number of wrongful convictions and led to procedural changes in police agencies and crime labs across the country, including at the FBI. On the other hand, the broader 2009 NSA study that cast doubt on a number of forensic specialties, including bite mark evidence and blood spatter analysis, hasn’t had the same impact. And previous revelations about sloppy crime lab work and bad forensics haven’t exactly led to government officials rushing to the courthouse to seek out and mitigate the harm done.

Eyewitness testimony reform could be a tough sell, both because it seems so powerful and convincing, and because it’s such a critical component of a large portion of police investigations. Still, Scheck seems optimistic that this study will convince more legislatures and police agencies to adopt the recommended procures to improve the quality of eyewitness testimony. Let’s hope he’s right.