Loftus and Palmer
Loftus and Palmer (1974)
Reconstruction of automobile destruction (the first experiment)
To investigate whether the use of leading questions would affect recall in a situation where participants were asked to estimate speed. This is a situation that could happen when people appear in court as eyewitness testimonies.
- The student participants saw videos of traffic accidents and had to answer questions about the accident.
- In experiment 1, the participants were asked to estimate speed of the cars based on a critical question: “About how fast were the cars going when they smashed into each other?”
- “Smashed” was replaced by words such as hit, collided, bumped or contacted in other conditions (experiment 2 is not included here).
- The mean estimates of speed were highest in the “smashed” condition (40.8 mph) and lowest in the “contacted” group (31.8 mph).
- The researchers calculated a statistical test and found that their results were significant at p ≤ 0.005. The results indicate that memory is not reliable and that memory can be manipulated by using specific words.
- The critical word in the question consistently affected the participants’ answer to the question.
- One explanation could be that the use of different words influenced participants’ mental representation of the accident, i.e. the verb “smashed” activates a cognitive schema of a severe accident and therefore speed estimates increase. It is not the actual details of the accident that are remembered but rather what is in line with a cognitive schema of a severe accident.
- This is in line with Bartlett’s suggestion of reconstructive memory. It could also be that participants simply had difficulties estimating speed. This cannot be ruled out.
- The experiment was conducted in a laboratory. There may be a problem of ecological validity.
- Maybe laboratory experiments on memory are too artificial.
- The fact that the experiment used students as participants has also been criticized because students are not representative of a general population.
- The films shown in the experiment were made for teaching purposes and therefore the participants’ experience was not the same as if it had been a real accident.
- The experiment was rigorously controlled so it was possible to establish a cause-effect relationship between the independent variable (the critical words) and the dependent variable (estimation of speed).