Download Classic Evidence: Loftus and Palmer (1974)

C1. Approach 4: The Cognitive Approach 3: Classic Evidence
Classic Evidence: Loftus and Palmer (1974)
Reconstruction of automobile destruction: an example of the
interaction between language and memory (pg 76-79)
Imagine that one day, you are walking in the city centre, and suddenly, out of nowhere, a car
screeches around the corner and hits another car. You witness the entire event. A few hours later,
you have to give a witness statement to the police. How accurate do you think your memory for the
event will be? What things could affect the accuracy of your memory?
Aim and Context
(Note: you will not be asked specifically about this, but you could include this information in other
questions, for example evaluating the study etc)
“I do solemnly, sincerely and truly declare and affirm that the evidence I shall
give shall be the truth, the whole truth and nothing but the truth”
The scene above is familiar to anyone who has ever watched TV. It is a cornerstone of our legal system that
without evidence, a person cannot be found guilty of a crime. This is why all witnesses must swear in court to
only tell the truth. However, what happens if the eyewitness believes that they are telling the truth, but really
they are providing testimony which is not 100% accurate? When a witness to a crime has nothing but their own
memory to rely on, can we be sure that their testimony is a real account of what actually happened?
What is eyewitness testimony (EWT)?
Eyewitness testimony is a legal term, referring to the use of eyewitnesses to give evidence in court. When a
crime has been committed, the police will often take “witness statements” from people who were present at
the time of the crime. This testimony is then used to help the police apprehend a suspect, and can also be used
as evidence in a criminal trial. EWT is a vital part of the justice system, but what happens
when it goes wrong?
The Innocence project is an organisation which works to clear the names of wrongly
convicted people. They claim that eyewitness misidentification is the greatest single
cause of wrongful convictions in the USA, convictions that were later overturned by DNA
evidence. This study by Loftus and Palmer took place in 1974. This is important to bear in
mind, as at this time DNA evidence was in it’s infancy, and was not routinely used in
police investigations the way that it is today. For many crimes, the only evidence
available was EWT.
So it would seem that EWT is not always accurate. One possible reason why EWT seems to be
so poor is because of the role of leading questions. Loftus defined a leading question as “a
question that either by its form or content, suggests to the witness what answer is desired, or
leads him to the desired answer”. These leading questions may be inadvertently used by the
police when interviewing witnesses after the event. Information received after an event can
have a retroactive interfering effect on our recollection; in other words, retroactive
interference occurs when later learning interferes with previous learning; i.e., incoming
information gets integrated and confused with our existing knowledge.
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
Therefore, the way in which the police interview witnesses after an incident may
alter their memory for the event. The language used in the questions may affect
their recall of an event. One example of this is when police ask about how fast a
car was moving. They may ask “How fast were the cars going when they hit each
other?” or “How fast were the cars going when they smashed each other?”. It
was Filmore (1971) who suggested that the words smashed and hit may imply
different rates of speed. These words lead the listener to assume different
consequences to the impacts to which they are referring, with hit being perceived
as gentler than smashed. Therefore, by changing just one word in a question, we may
be altering the memory of the witness.
Aims
Loftus and Palmer’s experiment was actually two experiments. They wanted to investigate in general how
accurate or inaccurate memory was. Specifically, they wanted to see the effect of leading questions upon
estimates of speed. Therefore there are two aims to this study.
Experiment 1
 To see if the speed estimates given by participants upon watching a video of a car crash
would be influenced by the wording of the question asked. They wanted to see if
participants who were asked a question with the word “hit” in it would give a different
estimate of speed than those who were asked the same question but with the word
“smashed”.
Experiment 2
 Loftus and Palmer also wanted to see if the leading questions just changed the responses
given to the questions, or whether the participant’s memories had actually altered as a
result of the leading questions.
Methodology
Use the information on page 76 and the text taken from the original article on the next page, and complete the summary
table for experiment 1 and 2.
Experiment 1
Experiment 2
Number and make-up of
participants
Research method used
Experimental design
Independent variable
Dependant variable
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
Procedures
Experiment 1
Using the information on page 76 and the text from the original article above, put the steps of the procedure of experiment 1
into the correct order.
After each film, each participant was given a
questionnaire.
The critical question was about the speed of the cars
Each participant watched 7 films depicting a traffic
accident. Each film lasted from 5-30 seconds, and
were presented in a different order to each group.
The blank was filled with one of the following words:
hit, smashed, collided, bumped or contacted
The participants were 45 students
The second part of the questionnaire was a series of specific
questions about the film
All participants were asked the question “How fast were the
cars going when they ______ each other?”
The first item on the questionnaire was asking the students
to simply give an account of what they had seen.
Why were the participants not told about the true aims of the study?
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
Why were the participants given a series of questions rather than just the critical question alone?
Experiment 2
Using the information on page 76 and the text from the original article above, create a bullet pointed list of the procedures
for experiment 2
What was the point of having a control group in the second experiment?
Findings
Experiment 1
A: Average estimate of speed for the four
videos (all participants)
Actual speed of
car crash
Mean speed
estimate (mph)
20
37.7
30
36.2
40
39.7
40
36.1
B: Average speed given for the different
verbs used
Verb used in
critical question
Mean speed
estimate (mph)
Smashed
40.5
Collided
39.3
Bumped
38.1
Hit
34.0
Contacted
31.8
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
Experiment 2
C: Average estimate of speed for the
two verbs
Verb Used in
critical question
Mean speed
estimate (mph)
Hit
8.00
Smashed
10.46
D: No of ppts who claimed to see
broken glass
Condition
Yes
No
Hit
7
43
Smashed
16
34
Control
6
44
E: Probability of saying yes to the broken glass question for different speed estimates
Condition
1-5
Smashed .09
Hit
.06
6-10
11-15
0.27
0.41
16-20
0.62
.09
0.25
0.50
Conclusions
Experiment 1
What can we conclude from table A?
What can we conclude from table B?
Explain how the results above support the theory of the effect of leading questions
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
Loftus and Palmer give two alternate explanations of the results. It may be that the participant’s response is
biased, in other words they are uncertain whether to say 30mph or 40mph, and the verb smashed biases their
response. Alternatively, the verb used in the question may actually causes a change in the participant’s memory
such that they see the accident as being more severe than it really was.
Experiment 2
What can we conclude from table C
What can we conclude from table D
What can we conclude from table E
Overall conclusions
In experiment 1, Loftus and Palmer gave two alternate explanations of the results (biased response and altered memory).
Which explanation do the results of experiment 2 support?
Loftus and Palmer suggest that memory is made up of two types of information. What are these and how do
they combine to make a memory? There is what actually happened, what was observed, and then there is
information gained after the event. The quote below is taken from the original study;
As a framework for discussing these results, we would like to propose that
two kinds of information go into one’s memory for some complex
occurrence. The first is information gleaned during the perception of the
original event; the second is external information supplied after the fact.
Over time, information from these two sources may be integrated in such a
way that we are unable to tell from which source some specific detail is
recalled. All we have is one “memory.”
Apply the above to explain
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
the results of this experiment.
Evaluation
Before we evaluate this study, can you think of any strengths or weaknesses?
Evaluation: Methodology and Procedures
The methodology used in this study was a lab experiment. What was a strength of using this methodology in this study?
One strength of
this study is that it is reliable. The study has standardised procedures, meaning that another researcher could
easily repeat this study to see if the results can be replicated. This study has been replicated by other researchers
many times and the results have been found to be consistent. This is a strength because it suggests that the
findings of this study are not just due to chance, but are meaningful, and supports Loftus’s conclusion about the
effect of leading questions on memory.
However, it could be argued that there are many factors that
lower the validity of the study. Remember, ecological validity
refers to how well the findings of the study can be applied to the
real world.
The study took place in a laboratory. What does this mean for the ecological validity of the findings?
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
The participants watched a video of a car crash, not a real car crash. What does this mean for the ecological validity of the
findings?
The participants were aware that they were in a study. What does this mean for the ecological validity of the findings?
Another major issue with this study that may lower the validity is the sample of participants used. All of the
participants were US college students. This sample may not be representative of the target population, and so
therefore the results may not be generalisable.
How might US college students differ from the general population? How might this affect the results?
Evaluation: Alternative Evidence
At the start of this topic, as a class we replicated a study into memory. This can be used as alternative evidence.
Carmichael (1932): Briefly describe what you did, what it found, and what it suggests. How does this link to Loftus
and Palmer? Does it support or contradict their conclusions?
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
The following are six studies into the effect of leading questions. You need to read them and match the findings to the
conclusions.
1: Loftus and Zanni (1975)
Showed participants a film of a car accident. Some
participants were asked “Did you see a broken headlight?”
whereas others were asked “Did you see the broken
headlight?” 7% of those asked about a broken headlight
reported seeing one, whereas 17% asked about the headlight
reported one. (There was not one in the video)
A: This research contradicts Loftus and Palmer, as it
suggests that in some circumstances, leading
questions have a limited effect on memory. It may
be that the information to be remembered in this
study was less subjective than estimating speed.
2: Loftus (1979)
Showed participants a series of pictures of a man stealing a
red wallet from a woman’s bag. 98% of participants were able
to identify the colour correctly. Later, Loftus used leading
questions to try and alter the participants recall. However,
they persisted in describing the purse as red.
B: This study develops the research into EWT.
Whereas Loftus and Palmer investigated the effect
of leading questions in altering memories of real
events, this research suggests that leading
questions can even plan memories that were never
there. It develops the theory that verbal
information can alter memory.
3: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 done it.
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.
4:Yullie and Cutshall (1986)
Interviewed 13 people who had witnessed an armed robbery
in Canada four months previously. They included two
misleading questions. They found that the participants were
not led by the leading questions, and the accounts that they
gave were very similar to those in their initial witness
statements
C: A criticism of Loftus and Palmer was that the
participants knew that they were in a study, and so
their behaviour may have been unnatural. This study
gets around this issue by demonstrating that recall
in real life, when participants do not know that they
will be asked to recall is still very poor.
D: This study has the advantage of letting us see the
effect of leading questions on real life
eyewitnesses. It suggests that the results of Loftus
and Palmer only apply in a laboratory setting, not in
real life cases. It supports the argument that Loftus
and Palmer’s research lacks ecological validity.
5: Loftus and Pickrell (1995)
Interviewed participants about events in childhood, planting a
false memory of being lost in a mall as a child (an event that
never happened). 20% of the participants came to believe that
this event had actually happened, and some even clung to the
memory after being debriefed.
E: A criticism of Loftus and Palmer’s experiment is
that judging speed is complex, and therefore the
participants more prone to being led by leading
questions. This research however demonstrates
that leading questions can actually cause
participants to remember something that was not
there. This supports Loftus and Palmer, as it
provides more evidence that leading questions can
alter the response given.
6: Braun et al (2002)
Participants who had visited Disneyland as a child were told
that they would be evaluating advertisements for it. Group
one were given an ad with no characters on it, group two
were given the same ad with a cardboard Bugs Bunny in the
corner of the room; group three were given an ad that had
bugs bunny on it, and the group four got the Bugs Bunny ad
and the cardboard Bugs Bunny. When asked later about
having met Bugs Bunny as a child, 30% of group 2 and 40% of
group 4 recalled meeting him. (Bugs Bunny is not Disney, so
this was a false memory)
F: This research build upon the results of Loftus and
Palmer, as it suggests that misinformation does not
need to be verbal for it to have an effect on recall.
False memories can be established by non
verbal/visual information.
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Use three colours to highlight research that supports, contradicts, or develops Loftus and Palmer’s research.
NOTE: In the exam, you would not need to include this many examples of alternative evidence. However, some
of these studies can be used for the next topic which is the contemporary debate about the reliability of EWT.
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Evaluation: Ethical issues and Social Implications
On the face of it, it may seem that there is little wrong with this study
ethically speaking. All the participants did was watch a video and
answer some questions. However, there are some ethical issues,
although in the scale of some of the other studies you have looked at
this year, the ethical concerns seem minor in comparison!
Deception and informed consent
In psychological research, it is important that participants receive fully informed consent. This means that before
a participant agrees to take part in a study, they need to be informed of what will happen in the study, what they
will be expected to do and what will happen to them. In this study, the participants were deceived about the
aims of the study. They were not told that the aim was to investigate the effect of leading questions.
Why could the participants not be told the true aims of the study?
Do you think the use of deception was justified in the use of this study? Explain why.
After this study, all the participants would have been debriefed, meaning that they would have been informed
about the full aims of the study and would be given the opportunity to ask any questions, and remove their data
from the findings if they so wished. In this way, the negative effects of deception could be overcome.
Psychological harm
Is there a possibility that the participants could have come to psychological harm during this study?
Social implications
What important information did we learn from this study? How could this have an affect on the real world?
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C1. Approach 4: The Cognitive Approach 3: Classic Evidence
NOTE: The effect of leading questions on EWT will be looked at in much more depth in the contemporary debate
next lesson.
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