Evaluation of Post-Event Information as a Factor Affecting EWT Flashcards
+ Allport and Postman (1947)
Allport and Postman designed a study in which white American participants were shown a picture of a white man threatening a black man with a razor blade. Their task was to describe the picture to a second participant, who described it to a third, and so on. Over half of the seventh participants described the black man not the white man as holding the razor blade - suggests how eyewitness testimony can be affected by schemas and stereotypes interfering with memory encoding of the actual event (- however, low ecological validity - participants were not under the same stress as in ordinary threat, and low population validity)
+ Loftus and Palmer (1974)
Loftus and Palmer found that participants who were asked how fast cars were going when they ‘smashed into’ each other gave higher speed estimates than those asked how fast the cars were going when they ‘hit’ each other - suggests EWT may be easily affected by leading questions (- low ecological validity, but highly controlled with independent groups)
+ Loftus and Zanni (1975)
Loftus and Zanni found that asking participants if they saw ‘the’ broken headlight rather than ‘a’ broken headlight after watching a film of a car collision increased the likelihood that they would report seeing one, even though there was no such headlight in the film - suggests EWT may be easily affected by leading questions, and speaking to other witnesses may affect recall of events (- however, low ecological validity, though highly controlled and so reliable)
- Yuille and Cutshall (robbery)
Yuille and Cutshall examined the recall of witnesses to a shooting in a Canadian town. A man had attempted to rob a gun shop, during the course of which the shop owner was shot. He returned fire, killing the robber. The incident occurred in broad daylights in front of a large number of witnesses. Some months afterwards, Yuille and Cutshall tracked down 15 witnesses and interviewed them. Examining their accounts, the researchers made several important findings:
- The witnesses were able to recall the incident in a great deal of detail
- There was a very high level of agreement between the accounts given by the different witnesses
- The witnesses’ accounts did not alter in response to leading questions
Refutes the idea that leading questions affect EWT, that weapon focus reduces accuracy of recall, and that anxiety affects EWT accuracy (high ecological validity and practical application to similar events)
