2) STORAGE - Passage of time, rehearsal,
meaning/simulation heuristics, post event
information (planted memories)
3) OUTPUT - Type of questioning, use of
interview protocols, confidence, false
memories.
3 main purposes of eyewitnesses: 1)
Assist police in identifying a suspect. 2)
Assist police in confirming their identity. 3)
Provide testimony at trial.
Yerkes-Dodson Law
An individuals performance can be enhanced to
an optimal point through arousal or motivation.
However, if the individual is over-stimulated it
could possibly lead to stress and failure. This is
evident in video games such as Modern Warfare
where you are motivated to do well and when
you end up achieving many kills, you may begin
stressing then die soon afterwards.
Elizabeth Loftus - Created a study
whereby she induced false
memories of being lost in a
shopping mall as a child crying.
After 3 suggested interviews 1/4 of
the participants developed a false
memory. A similar study whereby
people were given false memories
of knocking a punch bowl over a
bride and groom at a wedding
yielded false memory results of 1/4
of participants. Another study
created false memories of a
viscous animal attack. The
complete false memory rate was
26% and partial memory was 30%.
System variables
Live Line-up, photo line-up.
Fillers - A line up contains only one suspect and known innocent 'fillers'
(distractors or foils). Too much similarity between fillers and the suspect
confuse witnesses and cause a drop in accurate identifications. Dissimilar
fillers increase the risk that innocent suspects will be identified. Therefore fillers
should fit the verbal description of the perpetrator given by the witness but no
further similarities should be sought.
Prior instructions - Eyewitnesses need to be told prior to viewing a lineup that the
actual perpetrator might or might not be present in the lineup. The effect of this
variable is large and consistent. The instruction prevents witnesses from making the
assumption that the person who looks most like the perpetrator is them. Steblays
meta analysis shows a 42%reduction in mistakes when the instruction in given.
Show up - An identification
procedure with only the
suspect andf no fillers.
Sequential versus simultaneous - Standard police lineups show all 6 or 8
people at one time. With this method eyewitnesses tend to compare all
members to determine which one most loosely resembles the perpetrator
(relative judgement). In the sequential line up the witness is presented with one
lineup member at a time and they must make a decision whether each person
is the perpetrator before they are allowed to view the next person. The two
methods have the same correct identification rate when the offender is present
, when not present the rate was 26% higher.
Estimator Variables
Weapons Effect
Event Memory
The ability to describe
details of a critical event
such as which hand the
perpetrator used to hold
a gun. colour of a
getaway car etc.
System variables -
Exposure to misleading
questions (debate
remains over whether this
causes new memories,
alters old memories, or
the compliance effect).
Identification Memory
The ability to select
a perpetrator from a
photo or live lineup.
History
The U.S. Department of Justice released the
first national guide for collecting and
preserving eyewitness evidence in October
1999, called Eyewitness Evidence: A Guide
for Law Enforcement.
Hugo Munsterberg - In the early 1900 he
recognised that psychology had the potential
to inform the criminal justice system about the
nature of errors in eyewitness testimonies. He
focused on post event assessment
(identifying errors after they occurred).
In the late 1970s the focus was on preventing
errors before they occur.
Fisher and Geiselman analysed American police
interviews in 1980s, finding that police make
systematic, avoidable errors that limit the amount
of information the elicit. By asking too many closed
ended questions, frequently interrupting
eyewitness narratives, asking predetermined
inflexible questions,
The cognitive
interview
1) The social dynamics
between the witness and
interviewer. Achieved by
asking open ended
questions and allowing
ample time to finish their
answers
2) The eyewitness's memory. Recalling a traumatic event is difficult because it
requires focused attention and therefore can benefit from the application of
mnemonic principles. Achieved by conducting the interview at a slow pace,
and asking few and primarily open ended questions. Mnemonic instructions
such as reinstating the context of the original event and encouraging the
witness to recall the event though different retrieval pathways facilitate memory
by taking advantage of the encoding specificity principle. The cognitive
interviewer is also trained ask questions that are sensitive to individual
differences.
3) Communication between
the witness and interviewer.
Police fail at this because
they rarely communicate how
much information they need,
and at what level of detail.
The cognitive interviewer
encourages non verbal
expressions of knowledge
such as sketches.
Cognitive interviews
have elicited between
35 and 75% more
information than typical
police interviews in
studies, without an
increase in incorrect
responses.
Intended to increase the
amount of correct
eyewitness testimony. It
attempts to enhance
eyewitness recall by
improving 3 aspects of
the interview:
258 people convicted by juries in the
US have been freed by DNA testing,
200 of these cases involved incorrect
eyewitness identification.
General impairments of identification
performance - Witnesses assume the
culprit is in the line up. When they are
warned that a lineup may not contain
the culprit they are less likely to make a
selection. short exposure duration,
divided attention, and long viewing
distances, wearing a disguise, differing
race, undermine encoding.
Specific Suspect Biases - Confirming
feedback after a witness makes a positive
identification, presence of fillers in a lineup
who do not fit the description of the
suspect, misattributed familiarity due to
repeated identification procedures such as
seeing a mugshot before a line up.
Confidence Accuracy -
Only a weak and
inconsistent correlation.
The US Supreme court has identified self
confidence as 1 of the 5 factors to be
considered in assessing the competence
and admissibility of eyewitnesses,
Nisbett & Wilson’s study
found that people often
cannot report the actual
causes of their own
behaviour.
Videotape feedback can encourage self
observation. Retrospective self
awareness promotes in people a realistic
understanding of their own behaviour.
Retrospective self awareness increases
the accuracy confidence relation in 2
potential ways: retrieval-cue hypothesis
(forcing subjects to introspect, therefore
giving them access t previously overlooked
internal cues) or The self- perception
hypothesis (providing external information
that is necessary for indirect inferential
processes).
People including jurors
believe a confident witness
is an accurate one.
Eyewitness accuracy is a function of
memory where as confidence is a
function of social variables -
Eyewitnesses who make a mistaken
identification and are then told they made
the correct choice undergo confidence
inflation.Repeated questioning can also
cause confidence inflation.
Expert testimony -
Eyewitness experts criticise
biased lineups, failure to give
proper pre instructions in
order to encourage the
justice system to develop
better methods of collecting
eyewitness evidence. Courts
rarely suppress testimony
even when biased line up
procedures are used.
Media - Most media coverage
portrays the image that
eyewitness testimony is
unreliable and nothing can be
done to improve this.
DNA Exoneration - Forensic DNA was
introduced into the American courts in
1989. The vast majority of DNA
exoneration cases involve mistaken
eyewitness identification.
Janet Reno - US Attorney General read the 1996 report showing that 80%
of DNA exoneration cases involved incorrect eyewitness identification. She
later ordered a panel be formed in 1998 to address these concerns. A team
worked together tp create the guide. The police were supportive of national
guidelines, however prosecutors weren't. The guide calls for:
Establishing Rapport - Important at
many stages, from the operator who
takes the emergency call to the first
police officer on the scene and follow
up investigators. Witnesses are more
likely to invest their time and energy
throughout the investigation if their
personal needs are addressed.
Encouraging the witness to volunteer -
Eyewitnesses rarely provide unsolicited
information due to the interviewer
playing the dominant role. Asking open
ended questions - Blatantly suggestive
questions alter witness recollections.
Open ended questions are more apt to
be non leading and encourage
witnesses to take a more active role.
Typical interviews contain only 3 open
ended questions and witnesses were
interrupted on average 7.5 seconds
into their answers.
Cautioning against guessing- Eyewitnesses
may feel compelled to guess due to the
imbalance between social status of
themselves and the police. When enticed to
guess or not cautioned against guessing,
they will make many more incorrect
responses. One suspect per procedure -
Placing more than one suspect in a line up
inflates the chance of mistaken identification.
Selection of line up fillers - Where there is
limited encryption, the fillers should match
the suspect in significant features. Prelineup
instructions - Instructing the witness that the
suspect may or may not be present helps
eliminate the innocent.Avoiding post
identification suggestions - If an identification
is made avoid reporting to the witness any
information regarding their selection prior to
gaining a statement about certainty. The
sequential line up - This is the preferred
method for both live and photo line ups.
Shortcomings of the guide -
Not naming the sequential
line up as the preferred
method and not suggesting
double blind line ups.
Verbal overshadowing - A
phenomena where
pressing a witness to
describe a face diminishes
their ability to later
recognise that face.