Eyewitness testimony is unreliable due to flaws in human memory and perception. Memories are reconstructed rather than recorded, and are susceptible to biases and post-event information. Leading questions can influence a witness's response. While improvements have been made, eyewitness identification remains problematic in legal cases.
2. Psychologists have questioned the reliability
of eyewitness testimony since the beginning of
the 20th century.
This questioning of the credibility of
eyewitness testimony began with Hugo
Musterberg, who first developed the field of
Forensic psychology.
He specifically doubted the reliability of
perception and memory in his book "On the
Witness Stand" (1908).
3. Another reason why eyewitness testimony may
be inaccurate comes about due to an eyewitness's
memory being influenced by things that they
might hear or see after the crime occurred.
This distortion is known as the post-event
misinformation effect (Loftus and Palmer, 1974).
After a crime occurs and an eyewitness comes
forward, law enforcement tries to gather as much
information as they can to avoid the influence that
may come from the environment, such as the
media.
4. Eyewitness testimony is the account a
observervation given in the courtroom, describing
what that person observed that occurred during
the specific incident under investigation.
This recollection is used as evidence to show
what happened from a witness' point of view.
forensics now support psychologists in their
claim that memories and individual perceptions
are unreliable;
being easily manipulated, altered, and biased.
5. Loftus and Palmer (1974) carried out a study involving
the interaction between language and memory which
concerned how accurate eyewitness testimony (EWT) is
and the problems leading questions can bring.
Loftus and Palmer showed participants a short film clips
of car accidents and measured the effect of the use of
different verbs (such as ‘collided’, ‘contacted’ or
‘smashed’) .
when participants were asked about the speed of the cars
involved in the accidents,their answers were found
surprisingly unsimilar and affected by the tone,the way of
asking questions and the type of leading questions.
6.
7. Memory is "blurred
Memory fills in the gaps
Memory is biased by question retrieval
method
Memory changes over time and with
retelling
8. The images in our mind's eye are never as clear as an
actual perception.
People are much better at discriminating between two
objects when they are physically present than when one is
present and the other is in memory.
memory simply encodes the general gist of a scene.
For example, memory may code a memory of a person as
short, tall, young, fat, thin, old, white, black, rugged, etc.
or some combination.
These combinations may be some times benificial but not
for all the time.. it may be a reson of witnessing against a
suspect just because he is fat,thin,white,black or resembles
with the person he had seen.
9. Memory is a reconstruction, not a record.
The eyewitness will often have insufficient
information in the memory itself, so the
reconstruction may use the pieces of information
from other sources.
people confuse actual events with imagined
memories.
Eye witness may give imformation in the way they
have percived the situation, which may be totally
differ from the actual event,and May be totally
biased.
10. Eyewitness memories can be biased by the
questions asked at the time of retrieval.
Several famous studies have shown that the
question can supply information that the
eyewitness will incorporate into the answer.
The question can easily supply information that
helps fill in gaps in the respondent's memory.
11. Numerous studies have shown that memory changes
over time. The most notable effects include:
Eyewitnesses incorporate information learned after the
event into memory. For example, they may talk to another
witness and use information from the conversation to fill
in their reconstruction of the events. They may do this by
combining two memories into one or by using bias or
expectations of what probably was seen.
As people recall an event over and over, they drop
details from earlier versions and add new details to later
versions.
13. Goldstein & Chance (1985) suggest that
recognising faces is a complex skill that we develop
and improve upon. However, to do this we have to
have experience of the faces we want to recognise.
Western people tend to experience difficulties in
recognising faces of Japanese people. Similarly, to
many Asian or black people, whites all look very
similar.
these effects tend to come from lack of experience
in meeting people from the different groups. With
experience, we can soon learn to be more sensitive
to the differences in people’s faces.
14. The role of emotion also plays a significant part in
affecting the accuracy of eyewitness testimony due to the
fact that crimes are often frightening to a witness, even
more so if the criminal has a weapon.
This could even reduce or improve recall, either by
focusing the attention of the witness or distracting them.
Loftus (1987) introduced the ‘weapon effect’, this
suggests that once a weapon is seen by a witness, their
attention is drawn to it as it is a very frightening
experience therefore distracting the witness from the
criminals appearance, reducing the accuracy of the EWT.
15. Extreme witness stress at the crime scene or during the
identification process.
Presence of weapons at the crime (because they can
intensify stress and distract witnesses).
Use of a disguise by the perpetrator such as a mask or
wig.
A racial disparity between the witness and the suspect.
A lack of distinctive characteristics of the suspect such
as tattoos or extreme height
16. Law enforcement, legal professions, and
psychologists have worked together in attempts to
make eyewitness testimony more reliable and accurate.
Geiselman, Fisher, MacKinnon, and Holland saw
much improvement in eyewitness memory with an
interview procedure they referred to as the cognitive
interview.
The approach focuses on making witness aware of all
events surrounding a crime without generating false
memories or inventing details
17. In this tactic, the interviewer builds a rapport
with the witness before asking any questions.
They then allow the witness to provide an open
ended account of the situation.
The interviewer then asks follow up questions
to clarify the witness' account, reminding the
witness it is acceptable to be unsure and move on.
This approach guides the witness over a rigid
protocol.
When implemented correctly, the cognitive
interview found more accurate and efficient
without additional incorrect information being
generated.
18. Hogg & Vaughan (1996) have examined a number of
factors that lead to improved accuracy of eye-witness
testimony.
For example, it can help if the witness goes back over the
scene or the crime to reinstate additional cues. It also
helps if the witness was exposed to the person’s face for a
long time and give their testimony a very soon after the
crime.
More controversial is the idea that hypnosis will aid eye-
witness memory. Many studies have found no advantage
from using this technique (e.g. Smith, 1983). Indeed, Orne
et al. (1984) have shown that hypnosis can actually distort
recall.
19. Memory recall “is more akin to putting puzzle
pieces together than retrieving a video
recording,”
- Elizabeth F. Loftus,the University of California
20. People may pick up on suggestions communicated by the
hypnotist and incorporate these into their own memory — in
effect ‘leading questions’ are more likely to produce distorted
memories.
Hypnotised people sometimes ‘see’ things that were not there
and fail to report things that were there.
Confidence with which people give information is high even
though it may be incorrect. This may lead to false trails in the
investigation.
If hypnosis makes mental images more vivid, hypnotised
people may confuse these images with actual memories.
Editor's Notes
[Based on findings by Laurence & Perry (1983), Rathus (1987) and Hassett & White (1989).]