Principles of the Law, Policing 

The following entry contains the Black Letter, Comments, and Reporters’ Notes from Tentative Draft No. 2, Section 10.01. General Principles for Eyewitness Identification Procedures. This draft will be presented to membership at the 2019 Annual Meeting for approval. Until approved, this is not the position of The American Law Institute and should not be represented as such.

§ 10.01. General Principles for Eyewitness Identification Procedures

          Agencies should be cognizant of the scientific research regarding eyewitness perception and memory, and the limits of eyewitness evidence.


          a. Eyewitness identifications. Officers use a variety of different procedures to ask an eyewitness to identify a culprit, including: (1) showups; (2) photo arrays; (3) live lineups; and (4) mugshots and computer presentations of photos in which there is no designated suspect. In a showup, which usually occurs at or near the crime location and shortly after the crime occurred, officers present a single, live suspect to a witness. In photo arrays, officers present the eyewitness with a series of photographs, one of which is the suspect, and the others called “fillers,” or known non-suspects. Live lineups are less commonly used, in which the suspect and fillers are presented in person to an eyewitness. Additional procedures may be used in which officers do not have a suspect. If so, officers may show mugbooks or sets of photographs to see if the eyewitness can identify a suspect, or they may ask the eyewitness to help prepare a composite image or drawing of a culprit. This Chapter refers to these various procedures generally as “eyewitness identification procedures,” but refers to specific procedures when necessary.

          b. Scientific research. A substantial body of basic research examines how humans perceive images and form visual memory. That research has been complemented by applied research in the area of eyewitness identification. All of that research has resulted in a large body of knowledge concerning how to test visual memory accurately, including face identification, and a set of best practices that are recommended to test and preserve the memory of an eyewitness. Many traditional identification methods still used by agencies were not designed carefully or based on research. Such traditional methods can alter or deteriorate the memory of an eyewitness, including because those methods may be highly suggestive. Poor eyewitness identification procedures can result in situations in which the eyewitness cannot make an identification, or in false identifications and wrongful convictions of innocent persons.

          c. Procedures for eyewitness identifications. Agencies should use clear, written procedures for eyewitness identifications, developed with care and attention to the shortcomings of such identifications, as demonstrated by scientific research.

          Eyewitness identification procedures can themselves affect the memory of an eyewitness, and subpar procedures can outright alter the memory of an eyewitness. Constitutional rulings on the subject preceded the body of scientific research that has resulted in a set of best practices for eyewitness identification procedures. As a result, those rulings do not provide a well-informed constitutional floor. At best, they counsel against highly unnecessary and suggestive conduct by officers during identification procedures.

          Agencies should focus on practices informed by scientific research. That scientific research has resulted in consensus on a series of best practices. Certain other practices are not currently the subject of scientific consensus, and should be considered a matter of policy choice by agencies. Further, scientific research continues to advance and produce insights that can improve procedures for eyewitness identifications. Agencies that conduct eyewitness identifications should be responsive to developments in research and also in technology.



**Please note that citation formatting is limited by web fonts.** 

        Eyewitness identifications are a staple of criminal investigations. But their reliability has been called into question by decades of scientific research and an explosion of information about just how potentially unreliable such identifications can be. As the National Academy of Sciences explained in a landmark 2014 report summarizing the scientific research in the area of human visual memory, “it is well known that eyewitnesses make mistakes, and their memories can be affected by various factors including the very law enforcement procedures designed to test their memories.”  NAT’L RESEARCH COUNCIL OF THE NAT’L ACADS., IDENTIFYING THE CULPRIT: ASSESSING   EYEWITNESS    IDENTIFICATION   1   (2014).   In   particular,   the   hundreds   of DNA exonerations in recent years, the vast majority of which involved eyewitness misidentifications, have brought home the malleability and fragility of eyewitness memory. Id. Research examining what transpired in misidentifications that resulted in innocent persons being convicted has revealed the role that poorly designed and suggestive agency procedures can play. BRANDON L. GARRETT, CONVICTING   THE   INNOCENT:  WHERE CRIMINAL   PROSECUTIONS   GO WRONG 63-68 (Harvard University Press, 2011).

          Unfortunately, there is wide variability among agencies on the subject of eyewitness evidence. Many agencies have policies that are decades out of date, or they have no written policies at all. See, e.g., Police Executive Research Forum, A National Survey of Eyewitness Identification Procedures in Law Enforcement Agencies 46-47 (2013), at

          That said, false identifications and unsound lineup procedures are not a new problem. As the U.S. Supreme Court has put it: “The vagaries of eyewitness identification are well-known; the annals of criminal law are rife with instances of mistaken identification.” United States v. Wade, 388 U.S. 218, 228 (1967). In 1977, in adopting its current due process rule regulating eyewitness identification evidence, the Court emphasized how “reliability is the linchpin in determining the admissibility of identification testimony.” Manson v. Brathwaite, 432 U.S. 98, 114 (1977).

           At the time Manson was decided, however, little was known about what precisely had an impact upon the reliability of eyewitness identifications. As a result, the Supreme Court’s existing framework does not comport with scientific research. Although the Supreme Court’s due process test to assess eyewitness evidence asks whether police used suggestive identification procedures, any such suggestiveness can be excused based on a set of “reliability” factors. Manson, 432 U.S. at 114. The “reliability” factors adopted by the Court in Manson, having been already set out in its earlier ruling in Neil v. Biggers, 409 U.S. 188 (1972), ask that the judge examine: (1) the eyewitness’s opportunity to view the defendant at the time of the crime; (2) the eyewitness’s degree of attention; (3) the accuracy of the description that the eyewitness gave of the criminal; (4) the eyewitness’s level of certainty at the time of the identification procedure; and (5) the length of time that had elapsed between the crime and the identification procedure. Id. The Court did not assign any particular weight to these various factors.

          The Supreme Court more recently has held that when unreliability in eyewitness identifications is not due to intentional police action, it is not regulated under the Due Process Clause at all. Perry v. New Hampshire, 132 S. Ct. 716 (2012). The Justices in Perry stated that the Court did “not doubt either the importance or the fallibility of eyewitness identifications,” but held that state legislation, evidence law, and safeguards such as expert testimony and jury instructions should be relied on to ensure the accurate presentation of eyewitness evidence. Id. at 728-729.              

           A large body of scientific research has called into question the validity of many of the Supreme Court’s so-called “reliability” factors. For scholarly criticism in light of the social-science research, see, e.g., Gary L. Wells & Deah S. Quinlivan, Suggestive Eyewitness Identification Procedures and the Supreme Court’s Reliability Test in Light of Eyewitness Science: 30 Years Later, 33 LAW & HUM. BEHAV. 1, 16 (2009); Timothy P. O’Toole & Giovanna Shay, Manson v. Brathwaite Revisited: Towards a New Rule of Decision for Due Process Challenges to Eyewitness Identification Procedures, 41 VAL. U. L. REV. 109 (2006); Suzannah B. Gambell, The Need To Revisit the Neil v. Biggers Factors: Suppressing Unreliable Eyewitness Identifications, 6 WYO. L. 33         REV. 189 (2006).

           Several state courts have departed from the federal due process rule, relying on the research that has developed in the intervening decades. See, e.g., State v. Ramirez, 817 P.2d 774, 780-781 (Utah  1991) (altering  three  “reliability”  factors  to  focus  on  effects  of  suggestion);  State  v. Marquez, 967 A.2d 56, 69-71 (Conn. 2009) (adopting detailed criteria for assessing suggestion); Brodes v. State, 614 S.E.2d 766, 771 & n.8 (Ga. 2005) (rejecting use of eyewitness certainty); State v. Hunt, 69 P.3d 571, 576 (Kan. 2003) (adopting five-factor “refinement” of federal due process test).

           The Supreme Court’s acquiescent approach to eyewitness identification, and the current state of research, increase the need for laws and policies that adhere to our best understanding of the reliability of eyewitness testimony and the factors that in fact heighten or diminish reliability in any given case. And in fact, several state courts have rejected the Manson test entirely based on that scientific research. State v. Henderson, 27 A.3d 872 (N.J. 2011); State v. Lawson, 291 P.3d 673 (Or. 2012); Commonwealth v. Gomes, 22 N.E.3d 897 (Mass. 2015); Young v. State, 374 P.3d 395 (Alaska 2016). The New Jersey Supreme Court in its Henderson decision endorsed the use of pretrial hearings to examine eyewitness identification evidence, together with detailed jury instructions on the issue. State v. Henderson, 27 A.3d 872 (N.J. 2011). In contrast, the Oregon Supreme Court has endorsed review of the reliability of eyewitness evidence under its evidence rules. State v. Lawson, 291 P.3d 673 (Or. 2012). The Massachusetts Supreme Judicial Court has recommended more concise jury instructions on eyewitness identification evidence. Commonwealth v. Gomes, 22 N.E.3d 897 (Mass. 2015); see also Young v. State, 374 P.3d 395 (Alaska 2016). Each of these rulings has made it all the more important that agencies adopt best practices to ensure accuracy at the time that eyewitness identification procedures are conducted.

           Scientific evidence concerning human perception, vision, and memory provides a framework that should inform the collection and use—both pretrial and at trial—of eyewitness evidence, including through jury instructions and presentations by expert witnesses. As the National Academy of Sciences (NAS) has put it, “the best guidance for legal regulation of eyewitness identification evidence comes not . . . from constitutional rulings, but from the careful use and understanding of scientific evidence to guide fact-finders and decision-makers.” See NRC, IDENTIFYING THE CULPRIT, at 30; see also Final Report of the President’s Task Force on 21st Century Policing 2.4 (May 2015) (recommending adoption of identification procedures “that implement scientifically supported practices that eliminate or minimize presenter bias or influence”).

           In scientific terms, the law should take account of both estimator variables and system variables. Gary L. Wells, Applied Eyewitness-Testimony Research: System Variables and Estimator Variables, 36 J. OF PERSONALITY & SOC. PSYCHOL. 1546-1557 (1978) (first coining the terms “estimator” and “system variables”). Both types of variables can affect the memory of an eyewitness. Estimator variables are factors relating to the conditions of the crime-scene viewing, such as the lighting, the eyewitness’s eyesight, familiarity with the perpetrator, or race. Studies have shown that individuals display an “own race” bias, or a greater difficulty identifying persons of a different race. See NRC, IDENTIFYING THE CULPRIT, at 96. Estimator variables cannot be controlled by law enforcement. In contrast, system variables are factors associated with the procedures that officers use to obtain identifications by an eyewitness. System variables can be controlled by law enforcement.

          More than three decades of scientific research into eyewitness memory has begun to have an impact on how police conduct eyewitness identifications, as well as how judges regulate eyewitness evidence in the courtroom. That research informs the specific principles recommended in this Section. It also should inform the overall approach toward police investigations relying on eyewitness evidence, as well as subsequent judicial use and review of such evidence. Scientific research can inform each step of the process, from collection to use of eyewitness evidence in the judicial system. Although scientific consensus exists on the use of a range of crucial best practices, there is a lack of consensus on certain other factors and practices, making any recommendations on those topics more provisional and qualified. When further research is needed, these Principles note the appropriate qualifications.

          We note that the same protections against suggestion are important for “earwitness” identifications, in which a witness is asked whether a suspect’s voice can be recognized. Indeed, sometimes both face and voice recognition identification procedures are conducted. The same principles apply regardless of which memory task is involved in the procedure in question.

          Although the procedures described here apply to identifications by human eyewitnesses, facial-recognition technology is increasingly used to identify faces from video or images. Jose Pagliery, FBI Launches a Face Recognition System, CNN Money (Sept. 16, 2014), Such algorithms also can raise questions regarding reliability, as can the interpretation of the results of such technologies by human experts. John Nawara, Note, Machine Learning: Face Recognition Technology Evidence in Criminal Trials, 49 U. LOUISVILLE L. REV. 601, 604-607 (2011). As with the procedures for human eyewitnesses, agencies should evaluate the reliability of any technology adopted to use face recognition to identify faces or other biometric information.




Barry Friedman

Reporter, Policing Principles

Barry Friedman is the Jacob D. Fuchsberg Professor of Law and Affiliated Professor of Politics at NYU Law.  He is one of the country’s leading authorities on constitutional law, policing, criminal procedure, and the federal courts. He is the author of the critically-acclaimed The Will of the People: How Public Opinion Has Influenced the Supreme Court and Shaped the Meaning of the Constitution (2009), and the forthcoming book on policing and the Constitution, Unwarranted: Policing without Permission(February 2017). He is the founding director of NYU Law’s Policing Project.

Brandon L. Garrett

Associate Reporter, Policing Principles

Brandon L. Garrett is the L. Neil Williams, Jr. Professor of Law  at Duke Law School. His research and teaching interests include criminal procedure, wrongful convictions, habeas corpus, corporate crime, scientific evidence, civil rights, civil procedure and constitutional law. Garrett’s recent research includes studies of DNA exonerations and organizational prosecutions. In addition to numerous articles published in leading law journals, he is the author of five books, including: The Death Penalty: Concepts and Insights (West Academic, 2018) (with Lee Kovarsky); and End of its Rope: How Killing the Death Penalty Can Revive Criminal Justice (Harvard University Press, 2017).

Rachel A. Harmon

Associate Reporter, Policing Principles

Rachel Harmon is the F.D.G Ribble Professor of Law at the University of Virginia School of Law.  She teaches in the areas of criminal law, criminal procedure and civil rights, and her scholarship focuses on policing and its regulation. From 1998 to 2006, Harmon served as a prosecutor at the U.S. Department of Justice. After a brief stint at the U.S. Attorney’s Office in the Eastern District of Virginia, Harmon worked in the Civil Rights Division, Criminal Section, prosecuting hate crimes and official misconduct cases, many of which involved excessive force or sexual abuse by police officers.

Tracey L. Meares

Associate Reporter, Policing Principles

Tracey L. Meares is the Walton Hale Hamilton Professor of Law at Yale Law School. She has worked extensively with the federal government, having served on the Committee on Law and Justice, a National Research Council Standing Committee of the National Academy of Sciences from 2004–2011. Additionally, she has served on two National Research Council Review Committees: one to review research on police policy and practices, which produced the book, Fairness and Effectiveness in Policing: The Evidence and another to review the National Institute of Justice, Strengthening the National Institute of Justice. In November of 2010, she was named by Attorney General Eric Holder to sit on the Department of Justice’s newly-created Science Advisory Board; and in December 2014, President Obama named her as a member of his Task Force on 21st Century Policing.

Christopher Slobogin

Associate Reporter, Policing Principles

Christopher Slobogin is the Milton R. Underwood Chair in Law; Director, Criminal Justice Program; and Affiliate Professor of Psychiatry at Vanderbilt Law School. He has authored more than 100 articles, books and chapters on topics relating to criminal law and procedure, mental health law and evidence, and is one of the five most cited criminal law and procedure professors in the country.  Particularly influential has been his work on the Fourth Amendment and technology and his writing on mental disability and criminal law.

Jennifer Morinigo

The American Law Institute


Submit a Comment

Your email address will not be published. Required fields are marked *