memory: A comprehensive reference. New York:
Lawrence Erlbaum.
Wells, G. L., & Olson, E. (2003). Eyewitness identification.
Annual Review of Psychology, 54,277–295.EYEWITNESSMEMORY,
LAY BELIEFSABOUT
Lay beliefs about factors that influence the reliability
of eyewitness testimony have been assessed with a
variety of survey and experimental methods. When
compared with expert opinion about the effects of
these factors, the lay public frequently holds beliefs
that would be considered incorrect in the light of psy-
chological research on eyewitness memory.
A brief example provides the framework for under-
standing the relevance of lay beliefs about eyewitness
memory to legal decision making and criminal justice
procedures: A man presents a note to a bank teller and
tells everyone to get on the floor. A security agent
rushes the robber and is shot, but the thief escapes. Six
weeks later, a man named Simon Chung is appre-
hended. His picture is included in a collection of pho-
tos that is shown to the teller, the wounded security
officer, other employees, and the bank customers. The
teller and four customers identify Chung as the rob-
ber, whereas the bank security guard and another three
employees do not. Chung is charged with the crime
and the case proceeds to trial. The prosecution
believes that the five eyewitness identifications make
up a strong case against Chung. At trial, Chung’s
defense team presents a cognitive psychologist who, if
given the opportunity, will testify that a number of
features of the robbery and of the defendant reduce
the reliability of the identification evidence. Defense
counsel argues that jurors need to be aware of these
factors if Chung is to receive a fair trial. The judge
considers the expert’s testimony and, over the objec-
tions of the prosecution, decides that the expert should
be allowed to give evidence.
The proffering of expert testimony at trial occurs
frequently in common law countries. Judges decide
whether an expert will be heard on the basis of several
legal criteria, the most important of which for present
purposes is the judge’s assessment of the levels of lay
or juror knowledge about eyewitness testimony. If the
substance of an expert’s presentation is deemed to be
relevant to the case and to be outside the jurors’ ken,experience, or their common knowledge, expert testi-
mony intended to inform the jurors will likely be
deemed admissible. Only an expert in the specific
subject area may provide what is called opinion evi-
denceon the matter. Based on his or her own knowl-
edge and evaluation of the expert testimony, the judge
decides whether members of the jury are, as a group,
sufficiently informed and, if not, whether the quality
and reliability of their deliberations will benefit from
an expert’s presentation. Given the adversarial nature
of common law procedures, it is probable that oppos-
ing counsel may also proffer an expert who has a dif-
ferent interpretation of the importance of the relevant
eyewitness factors.
Regardless of the decisions made by judges in
these situations, there is little research that can tell us
whether their assessments of jurors’ lay beliefs
about eyewitness factors are likely to be correct.
Furthermore, although a topic of interest in its own
right, few studies have assessed whether judges (or
trial counsel) themselves hold correct beliefs con-
cerning eyewitness issues. The question raised here,
however, is the following: On what basis do judges
decide whether jurors are sufficiently informed (or
have “common knowledge”)? Scientific investiga-
tions of lay beliefs about eyewitness memory have
been conducted and, on occasion, the judges’ assess-
ments are informed by descriptions of this line of
research.
To describe the history, methods, and results of
that research, a few words are first needed about top-
ics within the field of eyewitness psychology—topics
about which the lay public may be examined as to
their beliefs and knowledge. Briefly, the field of eye-
witness memory research examines the myriad fac-
tors that mayinfluence witnesses’ recollections of an
event, the people present, their behaviors, and the
context in which the event occurred. The usual
scheme for categorizing these factors is based on a
distinction between (a) those that are under the con-
trol of the criminal justice system and, as a result,
may be manipulated to improve the reliability of eye-
witness evidence, such as the investigative interviews
and the suspect identification procedures, and (b)
those for which an impact on the reliability of testi-
mony may only be estimated and that are not under
the control of the justice system. This latter includes
a very large group of factors, such as the age of the
witness, lighting at the crime scene, witnesses’ levels
of stress, the confidence held by an eyewitness, andEyewitness Memory, Lay Beliefs About——— 299E-Cutler (Encyc)-45463.qxd 11/18/2007 12:42 PM Page 299