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Reconstruction of Automobile Destruction Loftus and Palmer (1974)

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Loftus and Palmer (1974). Reconstruction of Automobile Destruction. Aim. To investigate how information provided to a witness after an event will influence their memory of that event. Method. Two laboratory experiments Independent measures design IV = Verb used - PowerPoint PPT Presentation

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Page 1: Reconstruction of  Automobile Destruction

Reconstruction of

Automobile Destruction

Loftus and Palmer (1974)

Page 2: Reconstruction of  Automobile Destruction

To investigate how information provided to a witness after an

event will influence their memory of that event

Aim

Page 3: Reconstruction of  Automobile Destruction

Method

• Two laboratory experiments

• Independent measures design

• IV = Verb used

• DV = The estimate of speed or whether the P saw glass

Page 4: Reconstruction of  Automobile Destruction

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

Page 5: Reconstruction of  Automobile Destruction

Results – Experiment 1

VERBMEAN

ESTIMATE OF SPEED (mph)

Smashed 40.8

Collided 39.3

Bumped 38.1

Hit 34.0

Contacted 31.8

• 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.What do these results show?

Page 6: Reconstruction of  Automobile Destruction

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.

Page 7: Reconstruction of  Automobile Destruction

Results – Experiment 2

Response Smashed Hit Control

Yes 16 7 6

No 34 43 44

Did you see any broken glass?

The results show that the verb used in the original question influenced whether the

participants thought they had seen broken glass.

What do these results show?

Page 8: Reconstruction of  Automobile Destruction

Discussion

Loftus and Palmer suggest 2 explanations for the results of Experiment 1:

1. Response Bias: The different speed estimates occurred because the critical word (e.g. ‘smashed’ or ‘hit’) influences or biases a person’s response.

2. Memory is altered: The critical word changes a person’s memory so they actually ‘see’ the accident differently, i.e. more or less severe.

In order to prove this second point, L&P tested this in their second experiment – would people remember details that aren’t true?

Page 9: Reconstruction of  Automobile Destruction

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 person’s memory for an event: Firstly, the person’s own perception, and secondly information supplied after the event (such as leading questions)

Reconstructive Hypothesis

Page 10: Reconstruction of  Automobile Destruction

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

Page 12: Reconstruction of  Automobile Destruction

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?)

Page 13: Reconstruction of  Automobile Destruction

Evaluation - Usefulness

• This study has many applications:

# Police questioning witnesses

# Teachers asking/setting questions

Can you think of any others??

Page 14: Reconstruction of  Automobile Destruction

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?

Page 15: Reconstruction of  Automobile Destruction

Test Yourself…

1. Which of the following was not a cue word in the

experiment by Loftus and Palmer?

a) Smashed

b) Contacted

c) Knocked

d) Hit

The correct answer is… c) Knocked

Page 16: Reconstruction of  Automobile Destruction

Test Yourself…

2. The DV in the first experiment was…

a) Estimate of speed

b) The verb ‘smashed’

c) The question about broken glass

d) The film

The correct answer is… a) Estimate of Speed

Page 17: Reconstruction of  Automobile Destruction

Test Yourself…

3. In Experiment 1, how many experimental

conditions were there?

a) 1

b) 3

c) 5

d) 7

The correct answer is… c) 5

Page 18: Reconstruction of  Automobile Destruction

Test Yourself…

4. In Experiment 2, how many experimental

groups were there?

a) 1

b) 2

c) 3

d) 4

The correct answer is… b) 2

Page 19: Reconstruction of  Automobile Destruction

Test Yourself…

5. In Experiment 2, participants were tested immediately

and then asked to return for some more questions. How

long afterwards was this?

a) 1 day

b) 3 days

c) 1 week

d) 2 weeks

The correct answer is… c) 1 week

Page 20: Reconstruction of  Automobile Destruction

Test Yourself…

6. In Experiment 2, which group saw the most broken glass?

a) The ‘smashed’ group

b) The ‘collided’ group

c) The ‘hit’ group

d) The control group

The correct answer is…

a) The ‘smashed’ group

Page 21: Reconstruction of  Automobile Destruction

Test Yourself…

7. Which of the following is true?

a) Experiment 1 and 2 were both repeated measures

b) Experiment 1 and 2 were both independent measures

c) Only Experiment 1 was repeated measures

d) Only experiment 1 was independent measures

The correct answer is…

b) Experiment 1 and 2 were both

independent measures

Page 22: Reconstruction of  Automobile Destruction

Test Yourself…

8. The participants in this study were:

a) Children

b) Students

c) Teachers

d) Adults

The correct answer is…

b) Students

Page 23: Reconstruction of  Automobile Destruction

Exam Style Questions

1. a) In their study on eyewitness testimony, Loftus and Palmer

suggest that two kinds of information go into a person’s memory

for a complex event. Identify one of these two kinds of information.

b) What does the existence of these two

kinds of information tell us about memory?

2. From the study on eyewitness testimony by Loftus and Palmer

outline two features of the procedure that were standardised.

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.

4. Give one explanation for that difference.

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