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Classic Study: Loftus & Palmer 1974: Reconstruction of auto mobile…
Classic Study: Loftus & Palmer 1974: Reconstruction of auto mobile destruction: An example of the interaction between language & memory
AIM:
- To investigate whether leading Qs would influence the eyewitness accounts of people estimating the speed of a car
PROCEDURE: EXP 1:
- 45 students were shown 7 short film clips of a traffic accident
- After each clip, asked to give account of accident they'd seen & were asked to complete questionnaire which asked specific questions about the accident
- Length of the film clips ranged from 5-30 seconds
- Each 5 groups was shown film clips in different order
All participants received same questionnaire except for 1 critical Q was changed, the words were: ' smashed, collided, hit, bumped, contacted'
RESULTS:
Mean speeds (MPH) =
- Smashed = 40.5
- Collided = 39.3
- Hit = 38.1
- Bumped = 34.0
- Contacted 31.8
Results show people given the verb 'smashed' estimated fasted speed of the car compared to the other verbs. Verb 'contacted' produced slowest speed estimate. There was a difference of about 9mph in the estimates of the speed of these accidents
CONCLUSION:
Showed change of word can significantly affect a witness's answer to a question. Loftus & Palmer said it might be because of 2 reasons
- Participant was unsure of the speed being travelled & the verb used to describe cars created a bias & influenced their decision
- Wording in the Q causes a change in the participant's memory of the accident which makes them recall the accident as being more severe than it actually was
PROCEDURE: EXP 2:
- 150 participants watched a film of a multiple car accident
- Film lasted less than 1 min & accident itself was 4 seconds long
- Were then given questionnaire where they had to describe & then answer Qs on accident
Each participant given the same questionnaire which included a critical Q - there was 3 groups of 50 participants in each, the critical Qs were:
- How fast were the cars going when they 'smashed' into each other
- How fast were the cars going when they 'hit' into each other
- Final group weren't asked about the speed of the cars so received no critical Q
1 week later the participants had to go back & answer 10 Qs about the accident without watching the film clip again
All 150 participants asked amongst the other critical Q:
- Did you see any broken glass?
Was no broken glass in the clip, all answered yes/no
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CONCLUSION:
Findings from the 2nd experiment suggest the post-event info didn't simply create a response bias. It actually altered the person's memory of the event & generated expectations, such as the likelihood that there would be broken glass
EVALUATION
Strength
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COMPETING ARGUMENT
Watching car crash on video is very different experience from witnessing a similar event in real life
Film clip unlikely to elicit the same levels of emotional arousal as a real crash
Similarly, there's not the same emotional investment, there's no risk of someone going to prison should the estimate of speed be wrong
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Application
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Research into EWT & unreliability of human memory was a major consideration in the Devlin Report published in 1976
Among the recommendations was that juries shouldn't convict on the basis of a single eye-witness statement.
Loftus' work also arguably contributed to changes in the way the police question witnesses (e.g. cognitive interview) - shows Loftus' work has implications that stretch beyond the lab