M: Lesson 10: Eyewitness Testimony Flashcards
What is EWT?
- EWT us the evidence supplied to a court by people who see a crime based on their memory of the incident
- The evidence can include an identification of the perpetrator of that crime
- Juries are heavily influenced by EWT
- In the USA, 230 people convicted before DNA evidence was used in criminal investigations have been exonerated by DNA evidence.
- 75% were convicted based on the evidence supplied by eyewitness
What are leading questions?
Questions that influence the answer people give, they sometimes contain some misleading information
Leading questions Loftus and Palmer e
- Loftus and Palmer showed 45 students a video of a car crash and then asked them to estimate the speed that the car was traveling using one of five different verbs. How first were the cars going when they (contacted, hit, bumped, collided or smashed)
- Altering the verb used in the question had a significant impact on the estimated speeds the participants gave
- Participants in the ‘contacted’ condition estimated the speed as 31mph, however in the ‘smashed’ condition participants estimated the speed as 41mph.
- One week later all of the participants were asked the question ‘Did you see any glass?’, despite no broken glass being present in the video
- 32% of the participants in the ‘smashed’ condition of the study reported seeing the broken glass compared to the 12% in the ‘contacted’ condition.
Leading questions Loftus and Palmer e
- Loftus and Palmer showed 45 students a video of a car crash and then asked them to estimate the speed that the car was traveling using one of five different verbs. How first were the cars going when they (contacted, hit, bumped, collided or smashed)
- Altering the verb used in the question had a significant impact on the estimated speeds the participants gave
- Participants in the ‘contacted’ condition estimated the speed as 31mph, however in the ‘smashed’ condition participants estimated the speed as 41mph.
- One week later all of the participants were asked the question ‘Did you see any glass?’, despite no broken glass being present in the video
- 32% of the participants in the ‘smashed’ condition of the study reported seeing the broken glass compared to the 12% in the ‘contacted’ condition.
Positive Evaluation of Loftus and Palmer Leading Questions
It is a lab experiment and therefore highly controlled. Reduced extraneous variables, increasing validity. It is also more reliable as it can be easily replicated.
Negative Evaluation of Loftus and Palmer Leading Questions
- car crash might have a stronger emotional connection to the event, and may not be as susceptible to leading questions
- Lacks population validity (45 American students). Students are less experienced drivers. Unable to generalise results. Older and more experienced drivers may be more accurate in their judgements of speeds and therefore less susceptible to leading questions.
What is post event discussion?
- The memory of an event can be contaminated through discussing events with others due to misinformation (memory contamination).
- Also a desire of social approval can lead co-witnesses to reach a consensus view of what happened (memory conformity).
Post-Event discussion Gabbert experiment.
Gabbert et al put participants in pairs and got them to watch a different video of the same event so they each got unique details. 71% of witnesses who had discussed the event went on to mistakenly recall details that they could not possibly have seen for themselves., but that they had learned of during the discussion with their partner.
Positive evaluation of Gabbert Post-Event Discussion
Has population validity. Students and older adults were compared and there were no significant differences between these two groups. This allows us to conclude that post-event discussion affects younger and older adults in a similar way.
Negative evaluation of Gabbert Post-Event Discussion
Negative evaluation of Gabbert Post-Event Discussion
