Loftus and Palmer Flashcards
What is the aim, research method and experimental design of Loftus and Palmer
AIM - to see if leading questions affect participants speed estimates
RESEARCH METHOD - Laboratory experiment
EXPERIMENTAL DESIGN - Independent measures design
Why was it a lab experiment?
Why was it an independent measures design
LAB EXPERIMENT
IV was manipulated (verb in critical question)
DV was measured (speed estimates)
Under controlled conditions
INDEPENDENT MEASURES DESIGN
Experiment - divided into 5 groups each with different verb
Describe the samples
Experiment 1 - 45 students divided into five groups with 9 in each group
Experiment 2 - 150 students divided into three groups with 50 participants in each group
Opportunity Sampling
Describe the procedure of experiment 1
All were shown the same 7 film clips of traffic accidents taken from training films used by Seattle Police Department
After participants were asked to write an account of the accident and a series of questions (fillers)
Critical question ‘How fast were the cars going when they hit/contacted/bumped/collided/smashed?’ was hidden. The verb was changed (IV) to see if it affect speed estimates mph (DV)
What were the results of experiment 1
The verb smashed had fastest speed estimate (40.5mph)
The verb contacted had slowest speed estimate (31.8mph)
There was a 9mph difference in speed estimates
What could describe the difference in answers
Response bias - when participant is unclear what speed estimate, the verb gives them a clue to if its a high or low figure
Memory Distortion - the verb used actually alters a participants memory of the crash
Describe experiment 2
Participants watched a one-minute film with a car crash
then answered a questionnaire with a critical question hidden amongst other “How fast were the cars going when they …. into eachother”
One group had verb ‘smashed’ and the other ‘hit’ and a third group weren’t asked about speed
One week later, all participants were asked to complete another questionnaire which contained the critical question ‘Did you see broken glass’
The critical question was part of a longer series of questions and place in a random position on each participant’s question paper. There was no broken glass
What were the results of experiment 2
More participants in the ‘smashed condition than either the ‘hit’ or control groups reported seeing broken glass.
More than twice as many participants said they had seen broken glass when they had heard the verb ‘smashed’ compared to ‘hit’ or controls
12% of control group reported seeing glass = due to leading question
What were the overall conclusions
The verb used in a question influences a participants’ response
eg, the way its phrased influences answers given
People aren’t good at judging vehicular speed
Misleading post event information can distort and individuals memory
Assess Generalisability of Loftus and Palmer’s study
all participants are students
not representative of the wider population
students tend to be less experienced drivers so may have been more easily influenced by the verbs smashed/collided/ contacted etc. in giving their speed estimates
Assess the reliability of loftus and palmers study
standardised procedure and good controls
all watched same 7 film clips under controlled conditions
all had same filler questions
all watched same one minute film clip
so replicable and reliable
What are the applications of loftus and palmers study
Eyewitness testimony
Justice system don’t rely as heavily on this unless supported by other corroborating evidence
Police Training
Police trained on how to question witnesses without leading question
Assess the validiy of loftus and palmers study
Lacks ecological validity
1) participants lacked emotional involvement of real eyewitnesses.
2) participants may have felt recall was not as important as real witnesses
3) used questionnaires which isn’t like a real police interview.
Has experimental validity
1) leading questions were randomly hidden amongst other distractor questions
2) so participants unable to guess the aim so avoided demand characteristics
Lacks experimental validity
1) experimenter effects as participants may have felt they had to give a speed estimate when they used the word ‘smashed’
2) so did not come into conflict with the experimenter
Assess the ethics of Loftus and Palmer’s study
Deception
- they didn’t know that they were investigating the affects of leading questions on memory
Protection from Harm
- watching film clips of traffic accidents might have been distressing if they are related to a personal car crash
How does Loftus and Palmers study relate to key theme of memory?
Loftus and Palmer’s study provides evidence that information received after an event can affect a person’s memory of an event.
It shows how we can reconstruct out memories
