Loftus & Palmer (1974)

1. Loftus & Palmer (1974) Eyewitness testimony, Laboratory experiment

2. Aims • To see if leading questions are likely to affect someone's response • To see if the phrasing of a question affects estimate of speed

3. Procedure 1st Experiment • 45 ppts were involved • They were split into 5 groups and they each had to watch a film involving a car accident. (All watched the same film) • They were then asked questions about the car accident • There was a change in verbs in the question about the speed of the car (IV) • This was to see if the change in verb will change the estimate of the speed of the car. • The 5 groups were told 5 different verbs: • Smashed, collided, bumped, hit, contacted ‘How fast were the cars going when they ‘…’ each other?’ • This speed was estimated by the participants (DV)

4. Results The difference between the lowest and the highest estimate was 9mph, which is quite high.

5. Procedure 2nd Experiment • 150 students were involved • Part 1 - ppts were shown a film of a multiple car crash which lasted 4 seconds • Then they asked questions and one was about the speed • The ppts were divided into 3 groups • G1 asked - Smashed, G2 asked - Hit, G3 were the control group • Part 2– A week later ppts returned and asked another question about the filmed accident • ‘did you see any broken glass?’ - none in the actual film

6. Results The results show that the verb used in the original question influenced whether the participants thought they had seen broken glass.

7. Conclusions 1st Experiment • There was a relationship between the ‘strength’ of the word and estimate of the speed of the car • How the question was phrased had a significant effect on a witness’s answer • The form of the questions did affect the witnesses answers 2nd Experiment • Memory also relies on external information provided after an event, altering it to fit their schema. • Schema - is a pre-formed idea/plan of what should happen in a certain situation. • E.g. ACar accident - as soon as that phrase is said you probably think the car was speeding and that there was broken glass etc. If you are asked to give an eye-witness testimony on this accident, your schema may "fill in the blanks" of things that you didn't see or pay attention to. You fill it in with what you THINK should have happened, rather than what actually happened

8. Evaluation Strengths • This was a Lab experiment with clear controls. Therefore the study is replicable and can be tested for reliability • Quantitative data was gathered, so there was no interpretation from the research which meant that the results were objective. Weaknesses • The ppts may not have been under the emotional strain of a real accident so there may be lack of validity • Students were used to the study may not be generalisable to the whole population • There may have been demand characteristics as the student may have work out what was required