l&p (1974)- eyewitness testimony

Question 1

research method

Answer 1

exp 1- lab exp, independent measures design
The independent variable (IV) was the wording of a critical question hidden in a questionnaire. This question asked, “About how fast were the
cars going when they hit / smashed / collided / contacted / bumped each other?”
• The dependent variable (DV) was the estimated speed given by the participant

exp 2- lab exp, indepedent measures design

The independent variable (IV) was the wording on a question in a questionnaire:
- One group was asked, “About how fast were the cars going when they smashed into each other?”
- A second group was asked, “About how fast were the cars going when they hit each other?”
- A third group was not asked about speed.
• One week later, all participants were asked to complete another questionnaire which contained the critical question, “Did you see any broken
glass?”
• The dependent variable (DV) was whether the answer to this question was, “Yes/No.”

Question 2

sample

Answer 2

exp 1- 45 students in 5 groups.

exp 2- 150 students in 3 groups

Question 3

outline procedure

Answer 3

exp 1-
All participants were shown the same seven film clips of different traffic accidents which were originally made as part of a driver safety film.
• After each clip participants were given a questionnaire which asked them firstly to describe the accident and then answer a series of questions
about the accident.
• There was one critical question in the questionnaire: “About how fast were the cars going when they hit each other?

exp 2-
All participants were shown a one-minute film which contained a four-second multiple car crash.
• They were then given a questionnaire which asked them to describe the accident and answer a set of questions about the incident.
• There was a critical question about speed:
- One group was asked, “About how fast were the cars going when they smashed into each other?”
- Another group was asked, “About how fast were the cars going when they hit each other?”
- The third group did not have a question about vehicular speed.
• One week later, all participants, without seeing the film again, completed another questionnaire about the accident which contained the
further critical question, “Did you see any broken glass – Yes/No?” There had been no broken glass in the original film

Question 4

conclusions

Answer 4

The verb used in a question influences a participant’s response ie the way a question is phrased influences the answer given.
• People are not very good at judging vehicular speed.
• Misleading post event information can distort an individual’s memory