immediacy associated with the showup and the safe-
guards associated with a lineup.
The relatively informal in situ identification proce-
dure tries to take advantage of a naturally occurring sit-
uation where a witness gets a chance to observe a
suspect when the suspect does not know that he or she
is being observed for that purpose. As mentioned, this
often happens when a suspect is casually waiting in a
police station regarding an incident, usually with a
number of other people, and a witness to the incident is
asked to look through a door or window to see if he or
she recognizes anyone. Although this technique has
received little attention in the eyewitness research liter-
ature, the legal community typically accepts the results,
as long as the basic principles of the more common and
formalized procedures discussed below are included.
Also, it is common that a more formal identification
procedure will follow if an identification is made.
Viewing mug shots could also be construed as an
identification procedure, but the phrase identification
testimplies that the police have a suspect in mind and
that they are “testing” their hypothesis that the suspect
is the offender (as opposed to testing the witness’s
memory per se). A mug shot viewing is typically used
when the police do not yet have a suspect, so they
show potentially hundreds of photos of people who
have been arrested in the past for a similar crime
and/or who match a general description of the
offender. The result of a mug shot viewing could be a
relatively positive identification from an eyewitness,
but typically, the procedure just helps to narrow down
what the witness remembers about an offender (e.g.,
“He had beady eyes like Number 55, long blond hair
like Number 132,” etc.).
Finally, a witness could be asked to work with a
sketch artist to create a likeness of the offender, or use
a facial composite system, but these procedures are
more in the realm of witness recall as opposed to an
identification test.Constructing the Lineup
This aspect of identification procedures has received
the most attention from eyewitness researchers, and
several of the issues are addressed in detail in separate
entries. A prototypic lineup consists of one suspect and
at least five known-innocent fillers (variously called
distracters, foils, stand-ins, shills, and other terms).
Known innocentmeans that the police have no reason
to believe that the person could have committed
the crime in question, as opposed to meaning that theperson has never committed a crime in general. The
logical power of this single-suspect lineup is that the
identification of anyone other than the suspect is a
“known error,” because that person could not have
committed the crime. At that point, the police need to
consider several possibilities—the suspect is not the
offender, the witness’s memory is not sufficient to rec-
ognize the offender if he or she is present, the
offender’s appearance is sufficiently different from the
way he or she appeared at the time of the crime so that
the witness cannot recognize the offender, or perhaps
the witness is reluctant to identify the offender even if
he or she is present.
The number of fillers is not as important as the
degree to which the fillers serve to make the lineup
unbiased against the suspect, yet they should not be so
similar to one another and the suspect that it becomes
very unlikely for even a witness with a good memory
of the offender to recognize the offender if he or she is
present. The best-practice recommendation here is that
fillers be chosen based on their match to the witness’s
description of the offender, as opposed to their match
with the suspect’s actual appearance, with certain log-
ical qualifiers. Suppose, for example, that a witness
describes an offender as White, male, 30–35 years old,
and with a distinctive feature, such as an “insect tattoo
on his right cheek.” Suppose further that the suspect in
the case has a spider tattoo in the correct location. The
other lineup members should also be White, male,
30 to 35 years old, but they need only have an “insect
tattoo” on their right cheek (a bee, a scorpion, or even
different kinds of spiders) in order to qualify as good
fillers. Requiring the fillers to have the identical spider
tattoo or covering up the suspect’s tattoo and the cor-
responding spot on the fillers’ faces serves only to
remove a potentially useful memory cue for the wit-
ness to recognize the offender if he is in the lineup.Instructions to the Witness
The most common instruction, recommended by eye-
witness researchers since the early 1980s, is “The
offender may or may not be present.” The logic of this
instruction, supported by empirical research, is that it
provides witnesses with a “None of the above” alter-
native and counters to some extent any tendency of the
witness to assume that the police wouldn’t be bother-
ing with an identification procedure if they didn’t
have the “right” person. This tendency might lead to
witnesses guessing or choosing someone they don’t
feel very confident about, which is a primary concern366 ———Identification Tests, Best Practices inI-Cutler (Encyc)-45463.qxd 11/18/2007 12:43 PM Page 366