within an actual court case are system variables (Wells, Memon, & Penrod,
2006). System variables are divided into two categories; interviewing
eyewitnesses and identification of suspects. Interviewing eyewitnesses is the
process that involves recall memory and identification of suspects involves
recognition memory (Wells et al., 2006).
interviewing eyewitnesses began in the early 1900s (Wells et al., 2006). Alfred
Binet was the first to study suggestibility and William Stern initiated
eyewitness research in Germany (Wells et al., 2006). Modern day research is
heavily influenced by Elizabeth Loftus, who utilized a method of asking
questions of eyewitnesses to encourage them to adopt information that was
identified as misleading (Wells et al., 2006). Loftus’s style of research
opened the door for experimental studies and the forms of misinformation
imparted during the questioning of adult and children witnesses (Wells et al.,
The Cognitive Interview
Psychologist R. Edward
Geiselman developed the cognitive interview (CI) behind the influence from
police officers and legal professionals who encouraged improvement in the
outdated practices in police interviews (Wells et al., 2006). One of the focuses of the cognitive interview
is to produce effective communication between the interviewer and the witness (Wells
et al., 2006). The cognitive interview
consists of several phases in which the interviewer engages and establishes a
connection with the witness (Wells et al., 2006). The interviewer also encourages the witness to
provide a narrative account of the witness event. This is followed by probing
questions relating to the details the witness has provided (Wells et al.,
2006). The goal of the interviewer is to
interrupt as little as possible and allow the witness to dictate the subject
matter, sequence of questioning, and maintain active listening.
To begin the cognitive
interview, the interviewer attempts to build rapport with the witness. Building
rapport allows the witness to be more at ease and it minimizes the discomfort
and distress that is usually associated with sharing an intimate or fearful
experience with a stranger (Wells et al., 2006). In addition, building rapport allows for
increased accuracy by way of open-ended questioning. The optimal goal is to
transfer complete control to the witness (Wells et al., 2006).
Identifying Criminal Suspects
Identifying a criminal
suspect plays a very crucial part and, in most cases, is the most important
eyewitness evidence presented at trial. This becomes true when an eyewitness
makes the claim to have seen the suspect commit the criminal act (Wells et al.,
2006). The identification testimony then
becomes direct evidence of guilt and establishes a sense of accuracy in the
grand scheme of whether the suspect committed the crime or not. Eyewitness
testimony, regardless of whether the identification is direct or
circumstantial, is looked upon as accurate by the observers if the eyewitness
displays consistency and confidence (Wells et al., 2006).
Lineups are the primary
method for obtaining identification of criminal suspects (whether it is live or
photographic) and involves placing a suspect among fillers, asking the
eyewitness if he or she can identify the perpetrator (Wells et al., 2006). The two possible states of truth include the
suspect is the target and the suspect is not the target. With only one suspect
being involved in a lineup, the two states are equal to target-present and target-absent
lineups (Wells et al., 2006). In a
target-present lineup, two kinds of errors can be made. The incorrect rejection
(making no identification) or the identification of a filler (Wells et al.,
2006). Lineups are used in different variations whether it is simultaneous,
sequential, double blind, or target removal without replacement (RWR) lineups (Wells
et al., 2006).
Simultaneous and Sequential lineups
are the traditional police lineup utilized for which all members are presented
to the eyewitness at once (Wells et al., 2006). The witness chooses an
individual in the lineup who they believe is the perpetrator or reject the
identification of any of the individuals in the lineup if no one is deemed in
their eyes to be the suspect in question (Wells et al., 2006). In contrast, the
sequential lineup presents the lineup members to the eyewitness one at a time.
The witness has the opportunity to make a decision on the individual presented
in front of them before the next member in the lineup is presented if needed
(Wells et al., 2006). The number of members who will appear is not disclosed to
the witness. The idea behind the sequential lineup is to prevent the witness
from relying on relative judgment and using the process of elimination
(Wells et al., 2006). Despite a lower mistaken identification rate for
sequential lineups, it also yields a lower reduction in accuracy in regards to
identification (Wells et al., 2006).
A detective who is
aware of the person of interest usually conducts a police lineup. This person
is known as the suspect. All remaining members of the lineup are considered
fillers. Experiments have indicated an increase in the eyewitness identifying
the suspect when the lineup is administered by an individual who believes that
a particular lineup member is the suspect (Wells et al., 2006).A double-blind lineup is when the administer
is not aware of which lineup member is the suspect and which members are
fillers (Wells et al., 2006).
removal-without-replacement (RWR) lineup is when an eyewitness views either a
six-person or five-person lineup in which one member of the lineup is removed and
not replaced (Wells et al., 2006). The eyewitness is notified prior to the
lineup that the target might not be present. A removal-without-replacement
lineup is most effective when the memory of the witness appears to be weak (Wells
et al., 2006).
The utilization of
sketch artists or composite faces takes place when there is no clear suspect.
The original system, Identi-Kit used line drawings of facial features on transparencies
to create a composite (Wells et al., 2006). Currently, composite production
systems create faces by selecting features, which will then be combined into a
face (Wells et al., 2006).
Wells, G. L., Memon, A., & Penrod, S. (2006).
Eyewitness evidence: Improving its probative value. Psychological Science in the Public Interest, 7(2), 45-75.