Report
Urges Caution in Handling and Relying Upon Eyewitness Identifications in
Criminal Cases, Recommends Best Practices for Law Enforcement and Courts
WASHINGTON
-- A new report from
the National Research Council recommends best practices that law enforcement
agencies and courts should follow to improve the likelihood that eyewitness
identifications used in criminal cases will be accurate. Science has provided
an increasingly clear picture of the inherent limits in human visual perception
and memory that can lead to errors, as well as the ways unintentional cues
during law enforcement processes can compromise eyewitness identifications, the
report says.
“Human
visual perception and memory are changeable, the ability to recognize
individuals is imperfect, and policies governing law enforcement procedures are
not standard -- and any of these limitations can produce mistaken
identifications with serious consequences,” said Thomas Albright, director of
the Vision Center Laboratory at the Salk Institute for Biological Studies and
co-chair of the committee that wrote the report. The report focuses on
identifications of strangers rather than of family members or others well-known
to the witness.
Problems
with eyewitness identifications have long been documented, and many of the
cases in which DNA evidence later exonerated an innocent person involved at
least one mistaken eyewitness. Research
in recent decades has revealed many factors that can lead to such mistaken
identifications, the report says. Conditions during the commission of the crime
such as dim lighting, brief viewing times, stress, or the presence of a
visually distracting element such as a gun or knife can influence people’s
perceptions. Gaps in sensory input are filled by expectations that are based on
an individual’s prior experiences with the world, which can bias perceptions.
Studies also have shown that eyewitnesses are more likely to make mistakes when
making an identification among people of another race rather than when making
an identification of a person from the eyewitness’s own race.
In
addition, memory is often an unfaithful record of what was perceived through
sight; people’s memories are continuously evolving. As memories are processed,
encoded, stored, and retrieved, many factors can compromise their fidelity to
actual events. Although the individual may be unaware of it, memories are
forgotten, reconstructed, updated, and distorted.
Standardized
Procedures for Eyewitness IDs Needed
The law
enforcement community, while operating under considerable pressure and with
limited resources, is already working to improve the accuracy of eyewitness
identifications, the report says. However, these efforts have not been uniform
and often fall short because of insufficient training, the absence of standard
operating procedures, and the presence of actions and statements that
unintentionally influence eyewitnesses.
Caution
should be exercised in using eyewitness identification procedures and when
relying on these identifications in court, the report says. For example,
police departments should implement standardized procedures for handling
lineups, including using “double-blind” processes to prevent cues and biases
from creeping in. Judges should ensure, through expert testimony or jury
instructions, that jurors understand factors that may affect the accuracy of an
eyewitness identification in a particular case.
Many
police departments have begun to use sequential lineups – in which the
witnesses are shown one person or photo at a time -- instead of simultaneous
lineups, which show several people or photos at once. However, additional
research is needed to determine which procedure is superior, the report
says. It recommends the establishment of a National Research Initiative
on Eyewitness Identification to better understand best practices for conducting
lineups and photo arrays, assessing witnesses’ confidence levels, and
understanding other aspects of eyewitness identifications.
“At
this point, more research needs to be done to tell us whether sequential or
simultaneous lineups are more effective at producing accurate identifications,”
said co-chair Jed Rakoff, senior judge on the U.S. District Court for the
Southern District of New York. “But there are many practices that have been
validated by scientific methods and research that we already know can reduce
the likelihood of erroneous identifications, and law enforcement agencies and
courts should implement and follow them consistently.”
Best
Practices for Law Enforcement
To
increase the likelihood of accuracy in eyewitness identifications, the report
recommends that law enforcement agencies use the following practices in
handling eyewitness identifications.
§ Train all law enforcement
officers in eyewitness identification. An eyewitness’s memory of an incident can
be contaminated by a wide variety of influences, including interaction with the
police. All law enforcement agencies should provide their officers and agents
with training about vision and memory, practices for minimizing contamination,
and effective eyewitness identification protocols. Police officers should be
trained to ask open-ended questions, avoid suggestiveness, and efficiently
manage scenes with multiple witnesses (for example, minimizing interactions
among witnesses).
§ Implement double-blind lineup
and photo array procedures. Even if
a line-up administrator doesn’t verbally tell the witness which person in a
lineup or photo array is the suspect, he or she could still convey the
suspect’s identity through unintended body gestures, facial expressions, or
other nonverbal cues. Using a double-blind procedure, in which neither the
witness nor the administrator knows which person in the lineup or photo array
is the suspect, can avoid this inadvertent bias.
§ Develop and use standardized
witness instructions. The
report recommends the development of a standard set of easily understood
instructions to use when engaging a witness in an identification procedure.
Witnesses should be instructed that the perpetrator may or may not be in the
photo array or lineup and that, regardless of whether the witness identifies a
suspect, the investigation will continue. Such instructions should be used
consistently in all photo arrays and lineups and could either be pre-recorded
or read aloud by administrators.
§ Document witness confidence
judgments. Evidence
indicates that an eyewitness’s level of confidence in their identifications at
the time of trial is not a reliable predictor of their accuracy. The
relationship between confidence and accuracy is likely to be strongest at the
time of initial identification. Law enforcement should document the witness’s level
of confidence verbatim at the time when she or he first identifies a
suspect.
§ Videotape the witness
identification process. To
obtain and preserve a permanent record of the conditions associated with the
initial identification, the committee recommended that video recording of
eyewitness identification procedures become standard practice.
Best
Practices for Courts
The
federal standard governing the admissibility of eyewitness testimony is set
forth in the Manson vs. Braithwaite test under the Due Process Clause of the
U.S. Constitution. But the test was set out in 1977 before much of the applied
research on eyewitness identification had been conducted, and it includes
factors that are not diagnostic of reliability. 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, the
report says. It recommends best practices for judges to follow in assessing and
using eyewitness testimony.
§ Conduct pre-trial judicial
inquiry. Judges
have an obligation to ensure the reliability of evidence presented at a trial
and should make basic inquiries about eyewitness identification evidence being
offered. When assessing the reliability of an eyewitness identification, it is
important to know which eyewitness identification procedures the agency had in
place and the degree to which they were followed. If indicators of unreliable
eyewitness identifications are present, judges should follow applicable
procedural law in deciding whether to exclude the identifications or use a
lesser sanction. A judge could limit portions of the eyewitness’s testimony,
for example, or ensure that the jury is provided with a scientific framework
within which to evaluate the evidence.
§ Make juries aware of prior
identifications. The
accepted practice of in-court eyewitness identifications can influence juries
in ways that cross-examination, expert testimony, or jury instructions are
unable to counter effectively. Moreover, the passage of time since the initial
identification may mean that a courtroom identification is a less accurate test
of an eyewitness’s memory. Whenever the eyewitness identifies a suspect in the
courtroom, juries should hear detailed information about any earlier
identification, including the procedures used and the confidence expressed by
the witness at that time. An eyewitness identification should not typically
occur for the first time in a courtroom.
§ Use scientific framework expert
testimony. Many scientifically established aspects of eyewitness
memory are counterintuitive and may defy expectations, and jurors need
assistance in understanding the factors that may affect the accuracy of an
identification. In many cases this information can be most effectively conveyed
by expert testimony. Judges should have the discretion to allow expert
testimony explaining relevant research on eyewitness memory and
identifications. Local jurisdictions should make efforts to ensure that
defendants receive funding to obtain access to qualified experts.
§ Use jury instructions as an
alternative means to convey information. These instructions can be used as an
alternative way to convey information about eyewitness identification factors
the jury should consider. Jury instructions should, in clear language, explain
the relevant principles, allowing judges to focus the instructions on factors
relevant to the specific case. Appropriate legal organizations, together with
law enforcement, prosecutors, defense counsel, and judges, should convene a
body to establish model jury instructions regarding eyewitness identifications.
The
study was sponsored by the Laura and John Arnold Foundation. The National
Academy of Sciences, National Academy of Engineering, Institute of Medicine,
and National Research Council make up the National Academies. They are
private, independent nonprofit institutions that provide science, technology,
and health policy advice under a congressional charter granted to NAS in
1863. The National Research Council is the principal operating arm of the
National Academy of Sciences and the National Academy of Engineering. For
more information, visit http://national-academies.org.
