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Eyewitness Testimony

Eyewitness Testimony

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Eyewitness Testimony

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  1. Eyewitness Testimony • Reconstructive memory • Schema driven errors • Effect of leading questions • Other factors • Weapon focus • Effects of anxiety/arousal • Retrieval cues www.psychlotron.org.uk

  2. 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 www.psychlotron.org.uk

  3. 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 www.psychlotron.org.uk

  4. Computer Information Processing BANG! Can you wreck a nice beach? www.psychlotron.org.uk

  5. Can you wreck a nice beach? Schema Driven Processing Yes. I can recognise speech. www.psychlotron.org.uk

  6. Input Schema Output ‘Pickaxe’ ‘Turf cutter’ Bartlett (1932) www.psychlotron.org.uk Bartlett (1932)

  7. Bartlett (1932) • War of the Ghosts • When recalled by UK PPs: • Shorter • Less detailed • Some details changed (e.g. seal hunting changed to fishing) • More ‘Western’ structure www.psychlotron.org.uk

  8. 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 www.psychlotron.org.uk

  9. EWT: Schema Driven Errors • Past experiences • Assumptions about what usually happens • Stereotypes & beliefs about crime & criminals www.psychlotron.org.uk

  10. EWT: Leading Questions • Loftus (1970s onwards) • Effect of leading questions on recall • Leading questions introduce new information • Leading info may activate wrong schemas in witness’ mind • Consequently, witness may recall events incorrectly www.psychlotron.org.uk

  11. EWT: Leading Questions • Loftus’ studies using film/video/slides road accidents • ‘How fast were cars going when they hit…’ or ‘…when they smashed…’? • ‘Smashed’ led to higher speed estimates • ‘Did you see a/the broken headlight’? • ‘The’ produced more affirmative (incorrect) responses www.psychlotron.org.uk

  12. EWT: Leading Questions • Loftus’ research usually lab based: • Restricted samples (students) • Artificial stimuli (slides, videos, not real events) • Potential for demand characteristics to influence responses • No legal/moral consequences for inaccurate answers www.psychlotron.org.uk

  13. EWT: Leading Questions • EWT most affected by leading Qs when: • Witness believes questioner knows more than them • Witness does not realise they may be misled • Leading information is peripheral, not central • Leading information is not blatantly incorrect www.psychlotron.org.uk

  14. EWT: Weapon Focus • When a weapon is used to threaten a victim, their attention is likely to focus on it • Consequently, their recall of other information is likely to be poor www.psychlotron.org.uk

  15. EWT: Arousal Effects • Memory is most effective at moderate arousal levels • If the witness was in a state of extremely low or high arousal then recall may be poor performance arousal www.psychlotron.org.uk

  16. EWT: Retrieval Cues • Recall typically takes place in a different context to acquisition • Lack of retrieval cues (state and context) can inhibit recall • Reconstruction of the events (either imagination or simulation) can lead to enhanced recall www.psychlotron.org.uk