Reconstruction of

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Loftus and Palmer (1974)

• Reconstruction of
• Automobile Destruction

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Aim

• To investigate how information provided to a
  witness after an event will influence their
  memory of that event

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Method

• Two laboratory experiments
• Independent measures design
• IV Verb used
• DV The estimate of speed or whether the P saw
  glass

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Method Experiment 1

• 45 student participants were shown short video
  clips
• They were split into 5 groups, with 9
  participants in each one
• All of the participants were asked
• About how fast were the cars going when they
  ________ each other
• Each group was given a different verb to fill in
  the blank. These verbs were smashed, collided,
  bumped, hit or contacted. Therefore the
  independent variable was the verb used.
• The dependent variable was the estimate of speed
  given by the participants

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Results Experiment 1

• How the question was phrased influenced the
  participants speed estimates
• When the verb smashed was used, participants
  estimated that the cars were travelling much
  faster than when the verb contacted was used.

VERB MEAN ESTIMATE OF SPEED (mph)
Smashed 40.8
Collided 39.3
Bumped 38.1
Hit 34.0
Contacted 31.8
What do these results show?
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Method Experiment 2

• 150 student participants were shown a short film
  that showed a multi-vehicle car accident and then
  they were asked questions about it.
• The participants were split into 3 groups (with
  50 in each group).
• One group was asked
• How fast were the cars going when they hit each
  other?
• The second was asked
• How fast were the cars going when they smashed
  into each other?
• The third group was not asked about the speed of
  the vehicles
• One week later, all participants returned and
  were asked
• Did you see any broken glass?
• There was no broken glass in the film.

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Results Experiment 2
Did you see any broken glass?
Response Smashed Hit Control
Yes 16 7 6
No 34 43 44
What do these results show?
The results show that the verb used in the
original question influenced whether the
participants thought they had seen broken glass.
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Discussion

• Loftus and Palmer suggest 2 explanations for the
  results of Experiment 1
• Response Bias The different speed estimates
  occurred because the critical word (e.g.
  smashed or hit) influences or biases a
  persons response.
• Memory is altered The critical word changes a
  persons memory so they actually see the
  accident differently, i.e. more or less severe.

In order to prove this second point, LP tested
this in their second experiment would people
remember details that arent true?
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Discussion (cont)
The results again showed that the way a question
is asked can influence the answer given
This however was not due to a response bias, as
all participants were all asked if they had seen
any broken glass. This suggests that the leading
question had actually altered the participants
memory of the event.
Loftus and Palmer suggest that 2 kinds of
information go into a persons memory for an
event Firstly, the persons own perception, and
secondly information supplied after the event
(such as leading questions)
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Evaluation

• In your groups, discuss the following points

• How realistic were the studies?
• (Think about the differences between the tasks
  the participants did, and real life situations
  where you need to remember what you have seen)

• Who were the participants?
• (Could the results be generalised to other
  people?)

• How useful was the research?
• (How can the results of the study be applied to
  other situations?)

• Any other issues
• (Think about the type of tasks, the content of
  the video, etc)

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Evaluation Ecological Validity

• Ecological Validity This was low because it
  was a laboratory study, and the participants knew
  they were taking part in an experiment.
• In real-life situations there would be an
  element of surprise, so you might not be paying
  attention.
• There would be an increase in emotion such as
  fear, shock, etc. There may be victims.
• You might not be asked questions until some time
  later.
• You may have the opportunity to discuss what you
  saw with other people

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Evaluation Participants

• The participants were all students
• There are several ways in which students might
  not be representative of the general population.
• These may include age, driving experience,
  educational experience (i.e. they may be used
  to paying attention and being tested?)

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Evaluation - Usefulness

• This study has many applications
• Police questioning witnesses
• Teachers asking/setting questions
• Can you think of any others??

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Evaluation Other Issues

• How easy is it to estimate speed? It may be
  easier for some groups than others, e.g. taxi
  drivers or police officers.
• The driver of the car is not mentioned in the
  article what if they had been visible as an
  elderly woman or a young man?
• What if the car had been a Porsche or a Smart
  Car?

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Test Yourself
1. Which of the following was not a cue word in
the experiment by Loftus and Palmer?

1. Smashed
2. Contacted
3. Knocked
4. Hit

The correct answer is c) Knocked
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Test Yourself
2. The DV in the first experiment was

1. Estimate of speed
2. The verb smashed
3. The question about broken glass
4. The film

The correct answer is a) Estimate of Speed
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Test Yourself
3. In Experiment 1, how many experimental
conditions were there?

1. 1
2. 3
3. 5
4. 7

The correct answer is c) 5
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Test Yourself
4. In Experiment 2, how many experimental groups
were there?

1. 1
2. 2
3. 3
4. 4

The correct answer is b) 2
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Test Yourself
5. In Experiment 2, participants were tested
immediately and then asked to return for some
more questions. How long afterwards was this?

1. 1 day
2. 3 days
3. 1 week
4. 2 weeks

The correct answer is c) 1 week
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Test Yourself
6. In Experiment 2, which group saw the most
broken glass?

1. The smashed group
2. The collided group
3. The hit group
4. The control group

The correct answer is a) The smashed group
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Test Yourself
7. Which of the following is true?

1. Experiment 1 and 2 were both repeated measures
2. Experiment 1 and 2 were both independent
   measures
3. Only Experiment 1 was repeated measures
4. Only experiment 1 was independent measures

The correct answer is b)
Experiment 1 and 2 were both independent measures
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Test Yourself
8. The participants in this study were

1. Children
2. Students
3. Teachers
4. Adults

The correct answer is b)
Students
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Exam Style Questions
1. a) In their study on eyewitness testimony,
Loftus and Palmer suggest that two kinds of
information go into a persons memory for a
complex event. Identify one of these two kinds of
information.
(2)
b) What does the existence of these two kinds of
information tell us about memory?
(2)
2. From the study on eyewitness testimony by
Loftus and Palmer outline two features of the
procedure that were standardised.
(4)
3. In the study on eyewitness testimony by Loftus
and Palmer, the use of the verbs smashed and
hit led to different responses from the
participants. Outline one of these differences.

(2)
4. Give one explanation for that difference.
(2)