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Eye Witness Testimony. EWT. Lesson objectives. Identify factors affecting EWT Starter: Identifying different types of validity Loftus & Palmer (1974) you need to demonstrate that you know this study well enough to describe and evaluate it Pickel (1998) – D and E
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Lesson objectives Identify factors affecting EWT • Starter: Identifying different types of validity • Loftus & Palmer (1974) • you need to demonstrate that you know this study well enough to describe and evaluate it • Pickel (1998) – D and E • Revise for L & P timed exam qs next lesson
L & P: The critical question was How fast were the cars going when they • Smashed • Collided • Bumped • Hit • Contacted each other?
Results • Smashed 40.8 mph • Collided 39 mph • Bumped 38 mph • Hit 34 mph • Contacted 31.8 mph So what can be concluded from these findings?
Evaluate Loftus & Palmer (1974) in terms of validity Consider which validity you will comment on External or Internal or both? In terms of the study – is validity a strength or a weakness of Loftus & Palmer (1974)? (POINT) Explain what the evaluation issue means and why it matters……… (EXPLANATION) Explain why it is a strength or a weakness of Loftus & Palmer (1974) by providing a suitable example from the study…be specific…tie your answer to the study (EVIDENCE)
Evaluate Loftus & Palmer (1974) in terms of reliability In terms of the study – is RELIABILITY a strength or a weakness of Loftus & Palmer (1974)? (POINT) Explain what the evaluation issue means and why it matters……… (EXPLANATION) Explain why it is a strength or a weakness of Loftus & Palmer (1974) by providing a suitable example from the study…be specific…tie your answer to the study (EVIDENCE)
What is EWT? An eye witness is anyone who has witnessed an event (usually a crime). Testimony is a statement given by the witness as an account of what happened. List as many factors as you can think of that could affect the reliability of EWT …e.g…age
Age Eye sight Closeness to the event Mental faculty State of mind Emotional state Political, religious beliefs
factors affecting EWT Consider The nature of how we encode information into memory The nature of how we store information The nature of how we retrieve information from memory
What do we know about factors that can affect the reliability of EWT? 5 mins
Theories we have examined Reconstructive memory – Bartlett Schema driven errors - Carmichael Effect of leading words – Loftus & Palmer Depth of processing theory – Craik & Lockhart Trace decay theory – Hebb Cue dependent theory – Tulving Context dependent forgetting – Godden & Baddeley other factors …… effects of anxiety/arousal Age of witness, post event information
Reconstructive Memory • Bartlett (1932) • Memory is not a direct record of what was witnessed • What is encoded and how it is retrieved depends on: • Information already stored in memory • How this info is understood, structured and organised
Reconstructive Memory • Schemas • Knowledge structures that relate to commonly encountered objects, situations or people • Enable us to predict events, make sense of unfamiliar circumstances, organise our own behaviour • Act as filters to perception & recall
Computer Information Processing BANG! Can you wreck a nice beach? www.psychlotron.org.uk
Can you wreck a nice beach? Schema Driven Processing Yes. I can recognise speech.
Input Schema Output ‘Pickaxe’ ‘Turf cutter’ Carmichael (1932)
EWT: Schema Driven Errors • Witnesses to crimes filter information during acquisition & recall • Their schematic understanding may influence how info is both stored & retrieved • Distortions may occur without the witness realising
EWT: Schema Driven Errors • Past experiences • Assumptions about what usually happens • Stereotypes & beliefs about crime & criminals
According to Allport and Postman (1947) how did their ppts describe this scene? When asked to recall details of the picture, participants tended to report that it was the black man who was holding the razor shows that memory is an active process and can be changed to 'fit in' with what we expect to happen based on your knowledge and understanding of society (e.g. our schemas)
Clearly there are many factors that affect the accuracy of EWT There are many theorieswe can use to explain why this is Loftus & Palmer looked at the effect one word can make on estimates of speed They also looked at the effect of leading questions. Loftus then went onto find out more about the phenomena known as ‘weapons focus’ See Pickel (1998) what did Pickel find? how does this support EWT? Evaluation?
Factors affecting EWT Consider The nature of how we encode information into memory The nature of how we store information in memory The nature of how we retrieve information from memory Apply the information above to the 2 theories of memory and the 2 theories of forgetting we looked at last year– which parts of the memory process does each theory refer to? Levels of Processing Theory encoding storage retrieval Reconstructive Memory Theory encoding storage retrieval Cue dependent Theory of forgetting encoding storage retrieval Trace decay theory of forgetting encoding storage retrieval