Loftus and Palmer: Experiment 1
Loftus and Palmer (1974): study of the effect of the wording of questions on witness memory of car crashes.
Cognetive Psychology is concerned with the mental processes that allow us to deal with information.
AIM: To investigate the effect of questionning on an eyewitness memory for a car accident.
METHOD: A laboratory experiment using an independant measures design. 45 students were shown footage of 7 car crashes and asked how fast the cars were travelling when they 'smashed', 'collided', 'bumped', 'hit' or 'contacted' eachother (depending on the condition).
RESULTS: The average estimated speed varied according to the verb with 'smashed' leading to the highest speed estimates, and 'contacted' being the lowest.
Loftus and Palmer: Experiment 2
AIM: To establish whether the phrasing of the questions actually distorted to participants memory (in experiment 1) or if it was just response bias, by seeing if a false memory of 'broken glass' was created in the 'smashed' condition.
METHOD: 150 students were shown a film of a car crash less than a minute long, and then given a series of questions (like experiment 1). The students were divided into 3 groups, 2 of the groups where asked how fast were the cars going when they smashed or hit. The 3rd group was a control group where no question about speed was asked.
RESULTS: More than twice as many participants remembered seeing broken glass if they had the verb 'smashed' in the question.
CONCLUSION: The phrasing of the questions actually distorted witnesses' memory of the crash.
Loftus and Palmer: Evaluation
THE SAMPLE AND SAMPLING METHOD
- unlikely to be representative of the population as the participants had the same occupation (students), they were predominantly white, middle class and within a narrow age-range.
- because their teachers were running the study participants were likely to be more vulnerable to demand characteristics and social desirability.
- students are very used to taking in information and being tested on it.
- participants were less likely to be drivers and so their speed estimates may have been less accurate as a result of their lack of experience.
THE RESEARCH METHOD
- Lab experiments take place in high controlled enviroment making it possible to eliminate many extraneuos variable which means we can be confident that the study has high validity. (the IV is the thing affecting the DV)
- Lab procedures are straight forward to replicate. (high reliabilty)
- Low ecological validity as the lab enviroment is unlike real life.
Loftus and Palmer: Evaluation
- both the enviroment (lab) and the task were quite artificial and lacked realism. Participants had a better view of the crash than is typical in real life situations, but they were more likely to be relaxed about the situation and less motivated to remember details given that they were in a familiar and safe situation. In real life this would not be the case.
QUALITATIVE AND QUANTITATIVE DATA
- the data gathered in this study was quantitative. Statistics allow easy comparison of the conditions.
- On the other hand there was not opportunity for participants to comment either on their experience which might have added to the completeness of the findings.
- the results of the study have practical applications to real life, they can help the authorities understand how to question witnesses. The use of leading questions both by the police and in the courtroom is now tightly controlled.