Download Loftus and Palmer worksheet (NM)

Study 1 - Loftus and Palmer (1974)
Reconstruction of automobile destruction: an example of the interaction between language and
memory
Field of psychology: Cognitive
1. CONTEXT AND AIMS
“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”
Context
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 can not 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.
What does the Innocence Project suggest about the importance of (EWT)?
The study by Loftus and Palmer took place in 1974. Why is this relevant to the context?
One reason why the accuracy of EWT is often very
poor could be because of leading questions used
by the police 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.
“A leading question is a
question that either by
it’s form or content,
suggests to the wittness
what answer is desired,
or leads him to the
desired answer.
Elizabeth Loftus
Previous research has suggested that the mind does not work like a camera. Our mind
does not just take a picture of what it sees, and then reproduces this memory accurately. Our memories can
easily be altered by other information.
This can be demonstrated in the study by Carmichael (1932). What do the results of his experiment suggest?
Marshall (1969) reports that when Air Force personnel, who knew in advance that
they would be asked to estimate the speed of a vehicle, actually observed a car
travelling at 12 mph. their estimates ranged from 10 to 50 mph. Given that there are
such a range of estimates, it suggests that there might be variables which may cause
these inaccuracies such as the phrasing of a question to elicit a judgement of speed.
These results also show us that humans are poor at estimating speed.
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.
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 _____________________ upon
estimates of ____________________.
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.
2. PROCEDURES
As stated previously, Loftus and Palmer carried out two experiments. You need to know detailed procedures for
both of them, as well as participant numbers.
Use the information on pg 93 and the original text, complete the following two tables. When outlining the
procedure, be as detailed but as clear as you can. Imagine that someone else wanted to follow your description
to repeat the experiment. State what were the experimental and control groups (if relevant). You can use bullet
points if you wish.
Experiment 1
Number and make-up of
participants
Research method used
Experimental design
Independent variable
Dependant variable
Outline the procedure
Experiment 2
Number and make-up of
participants
Research method used
Experimental design
Independent variable
Dependant variable
Outline the procedure
Q1: Why were the participants not told about the true aims of the study?
Q2: Why were the participants given a series of questions rather than just the critical question alone?
Q3: In the first experiment, the order of the videos shown was varied from participant to participant. Why?
Q4: What was the point of having a control group in the second experiment?
3. FINDINGS AND CONCLUSIONS
Experiment 1
Findings
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
Summarise the results of table A
Summarise the results of table/graph B
Conclusions
Explain how the results above support the theory of leading questions
Loftus and Palmer give two alternate explanations of the results. Explain what is meant by:
Biased response
Change in memory
Experiment 2
Findings
A Average estimate of speed for
the two verbs
Verb Used in
critical question
Mean speed
estimate (mph)
Hit
10.46
Smashed
8.00
B No of ppts who claimed to see
broken glass
Condition
Yes
No
Hit
7
43
Smashed
16
34
Control
6
44
C – Probability of saying yes to the broken glass question for different speed estimates
Condition
1-5
Hit
.09
0.27
0.41
16-20
0.62
Smashed
.09
0.25
0.50
.06
6-10
Summarise the results of table A
11-15
Summarise the results of table/graph B
Summarise the results of table C
Conclusions
In experiment 1, Loftus and Palmer gave two alternate explanations of the results. Which explanation do the
results of experiment 1 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? (Pg 558 of original text and pg 94 in textbook)
Apply the above to explain the results of this experiment.
4. EVALUATING THE METHODOLOGY (pg 96)
Method: The methodology used in this study was a lab experiment. What was a strength of using this
methodology is this study?
________________________________________________________________________________
_____________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
In the first experiment, each of the verbs only had 9 participants. Why could this be an issue?
______________________________________________________________________________________________
______________________________________________________________________________________________
______________________________________________________________________________________________
______________________________________________________________________________________________
Reliability: This study has been replicated many times, and similar findings have been produced. What does this
suggest about the reliability of the study?
______________________________________________________________________________________________
______________________________________________________________________________________________
______________________________________________________________________________________________
______________________________________________________________________________________________
Validity: What aspects of the study affect the ecological validity?
The setting: ____________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
___________________________________________________________________________________
The participants watched a video of a car crash, not a real car crash: ________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
The participants were aware that they were in a study: __________________________________
________________________________________________________________________________
________________________________________________________________________________
_______________________________________________________________________________
Sampling: The sample consisted of US college students. Could there be issues with
generalisability? In what way are these participants different from the target population (all
people)? __________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
Ethical issues: refer back to your notes on ethics. Can you see any issues with this study?
_______________________________________________________________________________
______________________________________________________________________________
_______________________________________________________________________________
________________________________________________________________________________
_____________________________________________________________________________________________
_____________________________________________________________________________________________
5. CRITICALLY ASSESS WITH REFERENCE TO ALTERNATIVE EVIDENCE
Match the study to the conclusion
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)
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.
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 after.
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
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.
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)
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.
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.
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.
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.
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.
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.
Use three colours to highlight research that supports, contradicts, or develops Loftus and Palmer’s research.