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Eyewitness Testimony PowerPoint PPT Presentation


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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. Reconstructive Memory. Bartlett (1932) Memory is not a direct record of what was witnessed - PowerPoint PPT Presentation

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Eyewitness Testimony

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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


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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


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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


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Computer Information Processing

BANG!

Can you wreck a nice beach?

www.psychlotron.org.uk


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Can you wreck a nice beach?

Schema Driven Processing

Yes. I can recognise speech.

www.psychlotron.org.uk


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Input

Schema

Output

‘Pickaxe’

‘Turf cutter’

Bartlett (1932)

www.psychlotron.org.uk

Bartlett (1932)


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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


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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


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EWT: Schema Driven Errors

  • Past experiences

  • Assumptions about what usually happens

  • Stereotypes & beliefs about crime & criminals

www.psychlotron.org.uk


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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


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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


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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


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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


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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


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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


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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