Loftus and Palmer (1974) - leading questions
Reconstruction of Automobile Destruction
- Elizabeth Loftus looked at how subsequent information affects eyewitness accounts of events.
- She focused on the influence of (mis)leading information through visual imagery and the wording of questions in relation to eyewitness testimony.
- Loftus’ findings indicate that memory for an event that has been witnessed is flexible.
- If someone is exposed to new information during the interval between witnessing the event and recalling it, this new information may have effects on what they recall.
- The original memory can be modified, changed or supplemented.
- Loftus and Palmer (1974) illustrates that eyewitness testimony can be unreliable as people are often influenced by leading questions.
To test the hypothesis that the language used in eyewitness testimony can alter memory. They aimed to show that the cues within leading questions could distort eyewitness testimony accounts.
To test this Loftus and Palmer (1974) asked people to estimate the speed of motor vehicles using different forms of questions. Estimating vehicle speed is something people are generally poor at and so they may be more open to suggestion.
Procedure:
Experiment 1...
- 45 American students formed an opportunity sample.
- A laboratory experiment with 5 conditions.
- 1 of these was experienced by each participant - an independent measures experimental design.
- 7 films of traffic accidents. Mixed duration from 5-30 seconds. Presented in a random order to each group.
- After watching it participants asked to describe what had happened as if they were eyewitnesses.
- They were then asked specific questions, including the question “About how fast were the cars going when they (smashed / collided / bumped / hit /contacted) each other?”
- The independent variable was the wording of the question.
- The dependent variable was the speed the participants estimated.
Experiment 2...
- 150 students shown a 1 minute film featuring a car driving through the countryside followed by 4 seconds of a multiple traffic accident.
- Afterwards the students were questioned about the clip.
- The independent variable was the type of question asked.
- It was manipulated by asking 50 students 'how fast were the cars going when they hit each other?', another 50 'how fast were the cars going when they smashed each other?', and the remaining 50 participants were not asked a question at all (i.e. the control group).
- A week later the dependent variable was measured - without seeing the clip again they answered 10 questions
- One of these was placed randomly in the list: “Did you see any broken glass? Yes or no?" There was no broken glass in the clip.
Results:
Experiment 1...
- The estimated speed was affected by the verb used.
- The verb implied information about the speed, which affected the participants’ memory of the accident.
- The participants in the “smashed” condition reported the highest speeds, followed by “collided”, “bumped”, “hit”, and “contacted” in descending order.
Experiment 2...
Participants who were asked how fast the cars were going when they smashed were more likely to report seeing broken glass.
Conclusions:
- This research suggests memory is easily distorted by the questions asked and any information acquired after the event as these can merge with original memory causing inaccurate recall or reconstructive memory.
- The addition of false details to a memory is referred to as confabulation.
- This has important implications for the questions used in police interviews of eyewitnesses.
Evaluation:
Strengths
Weaknesses
Generalisability
Reliability
Applicability
Validity
Ethics
Strengths
- The use of estimates of speed in both experiments and the ‘yes’/’no’ question of the second experiment yielded quantitative data which meant there was no subjective interpretation of the data – therefore it can be said that the experiments have objectivity.
Weaknesses
- The student participants may have figured out what the purpose of the study was and tried to amend their answers to help out the researchers accordingly, there may have been demand characteristics.
Generalisability
- Only students were used, so the findings aren’t generalisable to all ages of the population.
- There was a small sample of 45 students in experiment one.
- A person of a different age group may be more or less alert and therefore give a different answer, or pay attention to more details.
- Experiment 2 has a larger sample of 150 students making it more generalisable.
- But experiment two would still lack generalisability to other occupations and age groups than students.
Reliability
- Laboratory experiments with strong, scientific controls (for example, they all watched the same film and were asked identical questions – except for the verb change), which means the study is replicable and can be repeated to test for reliability
- The reliability has its strengths as it was a laboratory based study, making it easily replicable.
- Any film clips and questions asked can be easily used again for different groups. This is a strength because it can check for consistency of results.
Applicability
- The study has applications within courts and criminal justice.
Validity
- The validity of the task is questionable, as the student participants are not likely to have been under the same emotional strain a real eyewitness of a horrific accident would have been, likewise they only watched video clips of the car crashes and did not witness them first-person, which may have affected their responses
- The validity of Loftus and Palmer’s study is questionable however as participants were having their memories altered but not for a real event, and this may not happen in reality due to it being too distressing.
- The study lacks ecological validity as a video isn’t a real event happening in front of the participants, and they knew it was going to happen so there is a lack of emotional connection which would be present in reality, possibly making them more alert to certain important details if asked to give EWT.
Ethics
- The strengths are the participants were only watching film clips of an event, not witnessing it in real life which can be distressing, showing protection of participants has been demonstrated. This is a strength because it did not breach this ethical guideline and there was no psychological harm done to any of the participants.
- Another strength is all participants gave informed consent, and were fully debriefed, which is good as they weren’t deceived in any way and knew they were going to watch car accident clips and answer questions on them so they were prepared.