Transcript Loftus and Palmer

Loftus and Palmer
Leading Questions
Context
• Carmichael et al. (1932)- presenting participants
with identical figures but different
accompanying words influenced the way they
reproduced images.
▫ E.g. Participants are given an image and a word
from list 1 or 2. They then reproduced it.
Reproduction Label list 1
Eyeglasses
Original
Label list 2
Reproduction
Dumbbells
▫ Memory is reconstructed which can be affected by
verbal labels.
Aim
• To test 2 effects of leading questions.
▫ Whether using different verbs suggesting a more
or less serious accident influenced…
 estimates of speed.
 Recall of damage caused in the accident.
Procedure- Experiment 1
• Sample: 45 students.
• Method: Variously sized groups watched 7 short
film clips of accidents.
• Measure/ DV: Questionnaire which asked them
to describe the accident. They were then asked a
series of questions including the critical question
on speed.
▫ Filler questions were used to disguise the aim of
the experiment.
• IV: Verb used
Procedure- Experiment 1 cont.
▫ About how fast were the cars going when they
[insert verb] each other?





Smashed
Collided
Bumped
Hit
Contacted
Less
Severe
to
More
Severe
Procedure- Experiment 2
• Sample: 150 students
• Method: Variously sized groups were shown a short clip
of a multiple car accident.
• IV: Grouped…
▫ Control: No critical question
▫ Group 1: Smashed
▫ Group 2: Hit
• Measure/ DV:
▫ Immediately following the film- questionnaire which asked
them to describe the accident. Series of questions including
the critical question.
▫ 1 week later- another questionnaire given to all participants
including a new critical question.
 Did you see any broken glass?
Findings- Experiment 1
• Verbs which suggested greater speed and impact
produced significantly higher estimates of speed.
Verb
Speed
Smashed
40.8
Collided
39.3
Bumped
38.1
Hit
34.0
Contacted
31.8
Findings- Experiment 2
• The ‘smashed’ group (10.4 mph) gave on average
a higher estimate of speed than the ‘hit’ group
(8mph).
• Participants were more likely to report seeing
broken glass in the ‘smashed’ condition.
• Participants who estimated higher speeds are
more likely to have reported seeing broken glass.
Conclusions
• The form of a question can systematically effect a
witness’s answer.
• Experiment 1 shows that an individual who is
uncertain of the speed can be influenced by response
bias. A more dangerous sounding verb would elicit a
higher estimate.
• Experiment 2 shows that the form of a question can
alter the witness’s mental representation of an
event, causing false recall.
• Memory of a complex event is an integration of:
▫ Perception of the original event
▫ Subsequent additional external information
Evaluation- Strengths
• Lab experiment: highly controlled.
▫ Eliminates extraneous variables, e.g. time allowed to
encode, and delay prior to recall.
▫ Minimised demand characteristics
 Randomisation of order of film clips in Exp 1, and
position of critical question in Exp 2.
 Filler questions.
▫ Increased validity and reliability.
• Ecological validity
▫ Real clips of car accidents and delay in questioning
reflects the experiences of eyewitnesses in court.
Evaluation- Weaknesses
• Lower ecological validity- witnessing a real car
crash:
▫ increased motivation
▫ greater emotional affects
▫ occur in context (films were very short)
• Sample- Unrepresentative.
▫ Can we generalise from students to all age groups
and demographics?
▫ Less experience of driving?
Test Yourself…
How good an eyewitness are you?
▫ Follow the link to find out:
http://www.youramazingbrain.org/asp/eyeanswe
r4.asp
Past Exam Questions
Section A
1. Summarise the aims and context of Loftus and Palmer’s (1974)
research ‘Reconstruction of Automobile Destruction: An Example
of the Interaction Between Language and Memory’. [12] 2011
2. Describe the findings and conclusions of Loftus & Palmer’s (1974)
research ‘Reconstruction of Automobile Destruction: An Example
of the Interaction Between Language and Memory’. [12] 2009
Section B
1. Evaluate the methodology of Loftus and Palmer’s (1974) research
‘Reconstruction of Automobile Destruction: An Example of the
Interaction Between Language and Memory’. [12] 2010
2. Evaluate Loftus & Palmer’s (1974) research ‘Reconstruction of
automobile destruction: an example of the interaction between
language and memory’. [12] 2009
Revision Aids
• Check out this link for quizzes and a summary of
Loftus and Palmer’s experiment:
 http://www.holah.co.uk/summary/loftus/