The Trouble with Eyewitness Identification Testimony in Criminal Cases

Greg Hurley, Knowledge and Information Services Analyst, National Center for State Courts

Research has found that eyewitness-identification testimony can be very unreliable. Law enforcement and the courts should follow the recommendations of social scientists when using and assessing eyewitness techniques, such as lineups, in criminal cases.

Social scientists have demonstrated through studies since the 1960s that there was significant reason to be concerned about the accuracy of the eyewitness-identification testimony used in criminal trials. Although witnesses can often be very confident that their memory is accurate when identifying a suspect, the malleable nature of human memory and visual perception makes eyewitness testimony one of the most unreliable forms of evidence.

Courts took very little notice of the problems associated with eyewitness identification until DNA evidence began to be used to exonerate criminal defendants, in some cases decades after they were convicted. In irrefutable cases of wrongful conviction, people both within and outside of the judiciary began to question the factors that led to each wrongful conviction. It became clear that the predominate cause was inaccurate eyewitness identification.

In 2014 the National Academy of Sciences (NAS) released a report, Identifying the Culprit: Assessing Eyewitness Identification. It was a very comprehensive review of studies that defined the nature of the problem and suggested solutions that can be employed to mitigate the impact. The report made it clear that this is a very complex problem, rooted in human psychology, which impacted police and courtroom practices. Following the NAS report, there have been a number of published articles further addressing the psychological underpinnings of the problem, police practices, and possible judicial solutions.

In 2016 Professor Keith A. Findley published “Implementing the Lessons from Wrongful Convictions: An Empirical Analysis of the Eyewitness Identification Reform Issues” (Missouri Law Review, vol. 81). Professor Findley’s article was important because he synthesized the prior work in this area and presented it in a comprehensible way for the legal community. He also addressed the mechanisms some state judiciaries have used to mitigate the problem.

It should be noted that the most critical reforms in the area of eyewitness identification will need to come from the law-enforcement community. However, the court plays an important role as the gatekeeper of evidence that can be used against a defendant.

In using lineups for purposes of eyewitness identification, the literature recommends the following reforms, as defined by Professor Findley:

  • Only One Suspect per Procedure
  • Proper Selection of “Fillers”
  • Unbiased Witness Instructions
  • Double-Blind Administration
  • Prompt Recording of Confidence Statements
  • Sequential Presentation
  • Limit the Use of Show-ups

It is suggested that only one suspect be included in a lineup, even if there are multiple suspects. Lineups are designed to be a test of memory, and including more than one suspect increases the chance that a defendant is selected by mere guesswork. This recommendation is equally applicable to paper lineups, in which the witness is shown photographs, and more traditional lineups of actual people. The “fillers” that are included in the lineup should be of the same race and age range and generally fit the description of the perpetrator. The actual suspect should not stand out due to some physical characteristic from the fillers. The instructions given to the witness should include a statement that the perpetrator may not be present in the lineup. This is critically important because research has demonstrated that this instruction decreases misidentifications. Ideally, the instructions would be standardized, with the same instructions read to every witness before a lineup.

Humans can subtly and unconsciously communicate information. This may be by eye movement, gesture, or other body movement. For this reason, the administration of lineups should be “double blind,” meaning that neither the witness nor the officer administering the lineup know which person is the suspect in the case. This eliminates any possible “contamination” of the lineup. When witnesses select the individual they believe is the culprit, their degree of confidence should be contemporaneously recorded. This is important because studies have shown that witnesses’ confidence in their selections can increase over time. Changes in the confidence level may later be a critical issue for the trier of fact when considering the credibility of an eyewitness’s identification.

A disadvantage of a traditional lineup, or a lineup of pictures when all the pictures are presented at once, is that a witness may compare people and select the person that most approximates what they remember. Although the literature is divided on this issue, most reports and studies suggest a sequential lineup may be more reliable. In a sequential lineup, people or pictures are shown to a witness one at a time. This causes the witness to focus exclusively on the person or picture presented, rather than engage in comparison.

The worst form of a lineup is the “show-up.” Show-ups are typically used in the field and are done shortly after a crime was committed. Law enforcement will cause a witness to view a single suspect who has often been located in the vicinity of the crime. The suspect is most frequently in handcuffs and may be showing other signs of distress, e.g., sweating. Obviously, these circumstances create a highly suggestive situation in which the risk of a misidentification dramatically increases. Although there may be some situations when police do not have probable cause to make an arrest and this may be the only viable investigatory mechanism they have, this practice should not otherwise be used.

Courts have historically taken the position that the credibility of witnesses is the province of juries. However, some state judiciaries have taken action to decrease the risk of misidentifications. For example, both New Jersey and Massachusetts have created new statewide jury instructions that give jurors guidance regarding the problems associated with eyewitness identifications and how they can better assess the credibility of that testimony. The New Jersey Courts also created Rule 3:11 (Rules Governing the Courts of the State of New Jersey), “Record of Out of Court Identification Procedure.” The rule requires that a law-enforcement officer must make a contemporaneous record of a lineup procedure, and the rule specifies what must be included in the record. If a law-enforcement officer fails to comply with the requirements of the rule, the results of the lineup are inadmissible. This is an excellent example of a judiciary using its evidentiary gatekeeping function to cause necessary change in law-enforcement procedures.  

To protect the public from wrongful convictions based on an eyewitness misidentification, it is important that both law enforcement and the courts take notice of recent developments on the issue in the social sciences. The courts must be aware of the malleable nature of human memory and the lineup practices used by law enforcement in the jurisdiction. Although they are downstream of the primary problem, the courts have the power and duty to properly instruct jurors, the ability to refuse to admit evidence that does not meet a fundamental level of trustworthiness, and the ability to work with justice system partners to improve the criminal justice system.