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Memory. Eyewitness Testimony. Watch this clip and answer the following questions. http://www.youtube.com/watch?v=Nfz6eqaLrc4. Questions. How many parked cars did you overtake before the roundabout? What coloured top was the person wearing who was talking into the passenger side?
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Memory Eyewitness Testimony
Watch this clip and answer the following questions • http://www.youtube.com/watch?v=Nfz6eqaLrc4
Questions • How many parked cars did you overtake before the roundabout? • What coloured top was the person wearing who was talking into the passenger side? • What was the registration no. of the white transit van? • How many people were waiting to cross at the first set of traffic lights? • What colour was the car that over took you?
Share your answers • Are they all the same? • Was the pedestrian male or female? Can you be sure? • Did the wording of the questions influence your answers?
Eyewitness Testimony • Important aspect of criminal trials. • Often very influential. • Juries can decide based on eyewitness testimony alone.
Reliable? Factors affecting? • How accurate do you think you would be in describing what you witnessed about the crash? • What factors might influence your statement? • Would being in a police station influence you? • Would the police officers have any effect on you, say in their manner or in their questioning technique, even in the language they used? • Would your impressions about police through television influence you?
Factors affecting testimony: • Anxiety / Stress • Reconstructive Memory • Weapon Focus • Leading Questions (Loftus and Palmer, 1974)
Anxiety/stress • Clifford and Scott (1978) found that people who saw a film of a violent attack remembered fewer of the 40 items of information about the event than a control group who saw a less stressful version. As witnessing a real crime is probably more stressful than taking part in an experiment, memory accuracy may well be even more affected in real life. • However, Yuille and Cutshall (1986) found that witnesses of a gun shooting had remarkable memory. Even after 5 months and despite leading questions.
Reconstructive Memory • Bartlett, 1932 – recall subject to our perception based on our culture, norms and experience. • We fit memories into our understanding. This means memories can be distorted or unreliable. • 'War of the Ghosts', Bartlett (1932)
Weapon Focus • As a witness you focus on the weapon making all other details secondary. • Loftus, 1987 • Selective attention. Do you remember the clip with the gorilla?
Loftus and Palmer, 1974 • Aim – to test if leading questions can distort eyewitness accounts. • M&P – Asked ppts (45 American students) to estimate the speed of vehicles after watching a clip of a car accident. A task ppl are generally poor at. The IV was the verb used in the question eg smashes, collided, contacted etc.
Conclusions • A week later ppts were asked if they saw any glass at the scene. Despite there being none ppts in the ‘smashed’ condition were much more likely to say yes. • This suggests that memories are open to distortion by language and that confabulation can occur (addition of false details to an existing memory). • How might you use this knowledge if you are: • A police officer • A lawyer?
Loftus and Zanni, 1975 • Did you see the broken headlight? VS • Did you see a broken headlight? • Ppts asked ‘the’ were twice as likely to answer yes.
Evaluation • Lacks ecological validity. • Consequences? • Closed questions.
For you to research: • Effect of individual differences on EWT: • Age • Occupation • This work has led to the development of cognitive interview technique. Research more about this technique.
