Eyewitness Testimony - Loftus & Palmer
Psychology: AQA A Level, topic 2.1.13
Loftus and Palmer (1974)
Eyewitness testimony is information given by a witness to a crime. Loftus and Palmer (1974) studied the effects of leading questions in two experiments.
EWT
- Eyewitness testimony is the information and details given to police by witnesses.
- Facts such as location/time/events of the crime scene and the appearance of the criminal are given.
- But they can be inaccurate because of both faults in memory, and leading questions.
Leading questions
- Leading questions are questions that potentially guide a witness to a certain answer.
- For example, a leading question could be:
- “Did you forget to do your homework?”
- A better-phrased question could be:
- “What happened with your homework?”
Experiment one
- Participants were shown a film of 2 cars crashing and were then asked questions about the events of the car crash.
- Questions included:
- “How fast do you think the cars were going when they hit?”
Method
- The word "hit" was then substituted for different participants.
- Examples of other words used instead of 'hit' were:
- Smashed.
- Bumped.
- Contacted.
- Collided.
Results
- Participants estimated different speeds when different words were used.
- Participants tended to give higher speeds when the word "smashed" was used. On average they estimated 41 mph.
- The word "contacted" gave the lowest average speed estimate of 32 mph.
Loftus and Palmer (1974)
Eyewitness testimony is information given by a witness to a crime. Loftus and Palmer (1974) studied the effects of leading questions in two experiments.
Experiment two
- Three groups of participants were used in this experiment:
- Group 1 were participants that were given the word ‘smashed’.
- Group 2 were participants that were given the word ‘hit’.
- Group 3 were participants that were given no suggestion of the speed of the car.
Method
- After one week, the participants were brought back in and asked the question:
- “Did you see any broken glass?”
- The correct response would have been ‘no broken glass’ as there was no broken glass seen in the film.
Results
- Group 1 (‘smashed’ group) were more likely to say that they had seen broken glass compared to the other two groups.
Conclusion
- Both experiment 1 and experiment 2 support the conclusion that leading questions (even just changing one word like ‘smashed’) can affect the accuracy of the eyewitness testimony.
Laboratory study
- This was a laboratory study and so had good control of extraneous variables.
- But because a film was shown and it was an artificial setting, it may not give an accurate depiction of eyewitness testimony.
- Real-life scenarios, such as a car crash, can be traumatic and emotionally arousing. So this trauma can also have effects on memory.
Demand characteristics
- Demand characteristics are when participants in a study may distort the results of the study by being aware of what the aim of the study is.
- The participants in this study may have been aware of its true purpose (by being asked leading questions, they may realise the study was about vulnerability to leading questions.)
- If this were the case, the reliability and validity of the results would be compromised.
Usefulness
- A strength of this study is the real-life implications.
- If police officers have this information, they can conduct more reliable and trustworthy police interviews.
- Police want to gain the most accurate facts, so they should be made aware of the effects of leading questions.
- Police should set guidelines and give information on how to formulate proper/non-leading questions.
Test yourself on Eyewitness Testimony - Loftus & Palmer
Which question did Loftus and Palmer ask the participants after they had watched the video?
Which group in Loftus and Palmer (1974) (experiment 2) were most likely to say that they had seen broken glass compared to the other two groups?
What is the main strength of the second experiment of Loftus and Palmer (1974)?