1. Elizabeth Loftus and John Palmer
3 Core study Reconstruction of automobile destruction: an example of the interaction between language and memory
Elizabeth Loftus and John Palmer

2. Aim
To investigate whether phrasing of a question can influence judgement of speed

3. Background
Marshall (1969) found that people had difficulty estimating the speed of cars even if they knew that they would be asked about it.
Daniel (1972) found that memory is effected by verbal labels.

4. Method: Experiment 1
Laboratory experiment
Independent design

5. Independent variable: Experiment 1
Verb used in question
smashed
collided
bumped
hit
contacted

6. Dependent variable: Experiment 1
Estimate of speed

7. Participants: Experiment 1
45 students
groups of various sizes

8. Procedure: Experiment 1
Seven films of traffic accidents were shown.
After each film, participants were given a questionnaire.
Firstly, they had to give an account of the accident.
Secondly, they had to answer some questions.

9. Critical question
About how fast were the cars going when they hit each other?
Other verbs substituted for ‘hit’:
smashed
collided
bumped
contacted

10. Results: Experiment 1
Mean speed estimates
smashed 40.8 mph
collided 39.3 mph
bumped 38.1 mph
hit 34.0 mph
contacted 31.8 mph

11. Conclusions
The form of the question can significantly affect a eyewitness’s answer to it.
This could be because of:
Response bias: uncertain participants use the verb to bias their response
Change in memory of accident: the verb makes the witness see a more or less severe accident.

12. Method: Experiment 2
Laboratory experiment
Independent design

13. Independent Variable: Experiment 2
Verb used in question:
smashed
hit
no question – control group

14. Dependent Variable: Experiment 2
Estimate of speed
Recollection of broken glass

15. Participants: Experiment 2
150 students
three groups of 50 students

16. Procedure: Experiment 2
One film of traffic accidents was shown.
Participants were given a questionnaire.
Firstly, they had to describe accidents in their own words.
Secondly, they had to answer some questions.

17. Critical question
About how fast were the cars going when they hit each other?
Other verbs substituted
smashed
The control group were not asked about speed.

18. Estimations of speed
Smashed mph
Hit 8.00 mph

19. Procedure cont’d
One week later the participants returned.
They answered a series of ten questions with critical question embedded randomly.

20. Critical question
Did you see any broken glass?
NB: There was NO broken glass in the film.

21. Answer to question on glass
Results: Experiment 2
Answer to question on glass
Yes No
Smashed 16 34
Hit 7 43
Control group 6 44

22. Conclusions
Confirmation that the form of the question can significantly affect an eyewitness’s memory.
This could be because:
Memory consists of two pieces of information
that gained at the moment of event
that gained after the event
Eventually both become one 'memory'
severity of verb 'smashed' distorts the memory of event

23. Controls
The same films were shown.
The questions were all identical except for critical question.
The critical question was embedded in other questions.
There was random placement of critical question.