affecting the accuracy of EWT, including anxiety, age of witness.
This little bit
is aimed at giving you some idea of how influential EWT can be in
convicting alleged criminals.
The Devlin Report
(1976) investigated the accuracy and importance of EWT following some
serious miscarriages of justice. The report examined over 2000 identity
parades in England and Wales in 1973 and followed them through to their
outcomes in court.
Of the 2000
parades 45% (900) resulted in a suspect being identified and out of
these 900 82% were convicted of the crime. In over 300 cases the EWT
was the ONLY evidence provided and 74% of these were convicted!
love EWT (and so do the police), both placing a lot of trust in it, EWT
may not be as accurate as the witnesses and the police like to think.
Fruzzetti et al 1992 concluded that thousands of people are convicted
each year on the basis of inaccurate EWT and Wells et al (1998)
investigated 40 American cases were people convicted by EWT were later
acquitted by DNA evidence.
highlighted this effect! She got participants to act as jurors and
decide the guilt or innocence of role playing thieves. When evidence
was merely circumstantial such as the suspect being seen entering the
building where the crime took place only 18% were judged to be guilty.
However, when the testimony of an eyewitness was added who claimed to
have seen the defendant commit the crime, this rose to 72%!!. Even when
the witness admitted that their eyesight was poor and that they were not
wearing glasses at the time, 68% of jurors were still prepared to
convict on their testimony alone!
In a classic
American study carried out by Buckhout 1980, a 13 second film clip of a
mugging was shown on TV. An identity parade of six suspects was later
shown and viewers asked to phone in and say who they thought had
Given that there
were only six suspects, chance alone would suggest that 17% would get it
right! In fact only 14% identified the person correctly suggesting that
EWT is not particularly accurate in some cases! I will regale you with
my own anecdotal evidence in class!!! (Something to look forward to
nature of memory
The main models
of memory, such as multistore, see memory has the storage of information
in a fixed form that does not change over time. So that a memory of
falling off of your bike at the age of 6 and who helped, how much blood
was spilt etc. will be the same in 10 years time as it is today and as
it was a few days after the event. However, reconstructive theories
believe memory to be flexible and constantly being altered in the light
of our experience and with constant retelling.
packages of knowledge (according to Cardwell), that we acquire through
experience. They help us to build up a picture of our World and enable
us to make predictions about our day to day lives. For example we will
have a schema for funerals, so that when we are in the unfortunate
position of attending one we are able to behave in accordance with
social norms without having to read up on them first. Our schema for
funeral will exist even if we have never been to a funeral before,
because we will have read about them, heard about them and seen them
portrayed in soaps etc. Similarly we will have schemas for going to
weddings, restaurants, for sitting exams, going clubbing, romantic dates
etc. Imagine going on your first date with nor prior expectations of
what is involved!!!
suggested a number of ways in which schemas affect our memory.
Selection: Information that does not fit current schemas is
Abstraction: we are inclined to recall the overall gist and
forget the detail.
Interpretation: schemas provide existing knowledge to help us
understand novel situations.
Normalisation: memories are distorted to fit with our existing
Retrieval: schemas (or schemata) help us fill gaps in our memory
by making a best guess.
Think how some of these
would tie in with reconstructing the scene of a crime!
For example, evidence suggests that
minor details are not remembered accurately but are added later in line
with what we would expect to have happened.
examples of research into schemas
Brewer & Treyens
(1981) got participants to wait one a t a time in a room for 35
seconds. The room looked like an office and contained 61 items. Most
objects were ones you would expect to be in an office, others such as a
skull, a brick and a pair of pliers, were not. Later they were asked to
recall the items in the office.
participants were most likely to recall the typical office fare, desk,
chair etc. Most of the errors were substitutions, i.e. people tended to
include items such as pens and telephones that would be in the ‘schema
for office’, but in this case weren’t.
were using their schema for ‘office’ to fill in the gaps in their
Note: this is a
favourite experiment for A2 coursework!
of the participants recalled the skull, presumably not in most peoples’
schema for an office! Schema plus tag theory attempts to explain
this. The idea being that we store our memory of the office with our
schema for office, but attach a marker (or tag) to indicate any
unexpected aspect. For a topical example, peoples’ memories of
Manchester United games may all seem pretty much the same and if asked
to describe one 3 weeks ago you may struggle and have to rely on your
schema for football to fill in the gaps. However, if something out of
the ordinary occurred such as United winning or not conceding a goal,
then that will be tagged onto the memory and you will be better able to
recall the details of the match. (Important note, do not use this has
an example. We all know how many MUFC fans there are out there,
Work in a
similar way to schemas but concern people and our prejudices. Main
Postman (1947) who showed participants pictures of a white man with a
razor threatening a black man on the subway. Later, participants tended
to recall the black man threatening the white.
showed participants a video of a couple eating a meal. They were told
that either the woman was a waitress or a librarian. This information
later influenced the participants’ description of the woman. I’ll leave
their descriptions to your own stereotypical views. (note: the
stereotype was more obvious if participants were told the person’s
occupation after watching the video).
schemas and stereotypes
suggests that we are only able to take in so much information at the
scene of a crime or incident. At a later date when we are asked to
provide greater detail then we rely on past experience (schemas) and
prejudices (stereotypes) to fill in the gaps. We use expectations to
reconstruct our memory.
The theory over
emphasises the inaccuracy of our memory.
provides no explanation of how schemas work.
Research into schemas: Bartlett’s War of the
theory was unfashionable for many years but has recently been recognised
as providing a valuable insight into the reconstructive nature of human
memory. His theory was based on Western recall of a native North
American folk story. He suggested that we make the following
alterations in such cases:
tended to add material to justify parts of the story.
Omissions: parts of the
story, particularly those difficult to understand, were left out.
Changes of order: the
storyline was rearranged in an attempt to make sense out of it.
Distortions of emotion:
people added their own feelings and attitudes to the story.
Changers: Sir Frederic Bartlett
The War of the Ghosts
One night two young men from Egulac went down to the river to hunt seals
and while they were there it became foggy and calm. Then they heard
war-cries, and they thought: "Maybe this is a war-party". They escaped
to the shore, and hid behind a log. Now canoes came up, and they heard
the noise of paddles, and saw one canoe coming up to them. There were
five men in the canoe, and they said:
"What do you think? We wish to take you along. We are going up the river
to make war on the people."
One of the young men said,"I have no arrows."
"Arrows are in the canoe," they said.
will not go along. I might be killed. My relatives do not know where I
have gone. But you," he said, turning to the other, "may go with them."
one of the young men went, but the other returned home. And the
warriors went on up the river to a town on the other side of Kalama. The
people came down to the water and they began to fight, and many were
killed. But presently the young man heard one of the warriors say,
"Quick, let us go home: that Indian has been hit." Now he thought: "Oh,
they are ghosts." He did not feel sick, but they said he had been shot.
the canoes went back to Egulac and the young man went ashore to his
house and made a fire. And he told everybody and said: "Behold I
accompanied the ghosts, and we went to fight. Many of our fellows were
killed, and many of those who attacked us were killed. They said I was
hit, and I did not feel sick."
told it all, and then he became quiet. When the sun rose he fell down.
Something black came out of his mouth. His face became contorted. The
people jumped up and cried. He was dead.
Remembering, 1932/1995, p. 65)
Being a native
North American story the narrative contains words, concepts and ideas
different to ones that as Westerners we are used to. As a result when
we are asked to retell the story we make alterations. These are based
on our own schemas, stereotypes and expectations.
Look at the list
of alterations Bartlett suggested (previous page) and try to spot
examples of them in the participant’s version below:
War of the Ghosts:
Two men from Edulac went fishing. While thus occupied by the river they
heard a noise in the distance.
"It sounds like a cry", said one, and presently there appeared some men
in canoes who invited them to join the party on their adventure. One of
the young men refused to go, on the ground of family ties, but he other
offered to go.
"But there are no arrows", he said.
"The arrows are in the boat", was the reply.
thereupon took his place, while his friend returned home. The party
paddled up the river to Kaloma, and began to land on the banks of the
river. The enemy came rushing upon them, and some sharp fighting ensued.
Presently some one was injured, and the cry was raised that the enemy
The party returned down the stream, and the young man arrived home
feeling none the worse for is experience. The next morning at dawn he
endeavoured to recount his adventures. While he was talking something
black issued from his mouth. Suddenly he uttered a cry and fell down.
His friends gathered round him.
But he was dead.
(from Bartlett, Remembering, 1932/1995, p. 66 -- transcript of a
recall protocol taken after 20 hours)
The story above is by
way of illustration. There is no need to learn the detail, only what it