Write them down

Write them down

Did you note down ‘sweet’ and ‘angry’?

Learning outcome

• With reference to relevant research studies, to what extent is one cognitive process reliable?

• Our cognitive process will be Memory-specifically reconstructive memory.

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?

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Schema Driven Processing

Yes. I can recognise speech.

Can you wreck a

nice beach?

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Bartlett (1932)

‘Pickaxe’

‘Turf cutter’

Input OutputSchema

Bartlett (1932)

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Bartlett (1932)

• War of the Ghosts

• When recalled by UK ppt’s:– Shorter– Less detailed– Some details changed (e.g. seal hunting

changed to fishing)– More ‘Western’ structure

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Allport and Postman (1947)

• Showed ppt’s a picture of a black man and a white man in an argument.

• White ppt’s incorrectly remembered the black man as the the one who was holding the cutthroat razor.

Reasons for inaccuracies in memory

• Reason 1

• Memories are reconstructive (Bartlett 1932 and Allport and Postman 1947) because information processing is schema driven.

Why does this matter?

• The reliability of memory has interested psychologists due to its repercussions within the legal system.

• Court cases are especially dependent on the reliability of eyewitness testimony (EWT)

Eye-witness testimony (EWT)

• Eye witness testimony is evidence supplied by people who witness a specific event or crime, relying only on their memory.

• Statements often include descriptions of the criminal (facial appearance and other identifiable characteristics)

• Subsequent identification• Details of the crime scene (eg the

sequence of events, time of day, and if others witnessed the event etc).

How accurate is eyewitness testimony?

• In 1984, American college student Jennifer Thompson was raped at knifepoint by a man who burst into her flat.

• During the ordeal she concentrated on every detail of her attacker so that she could later accurately recall him.

• Later that day she worked with police to compose a sketch of her assailant.

• A few days later she identified Ronald Cotton as the rapist and picked him out of an identity parade.

• On the strength of her EWT Ronald Cotton was imprisoned. Jennifer was so sure of his guilt and wanted him electrocuted.

• In 1995, after serving 11 years in prison, DNA evidence proved that Ronald Cotton was innocent and he was released.

How accurate is eyewitness testimony?

• In the USA, in more than 100 convictions in which people have later been shown to be innocent by DNA testing, 75% of them were convicted on the evidence of an eyewitness.

• There is the serious prospect that innocent people have been executed in the USA on the basis of EWT.

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

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EWT: Schema Driven Errors

• Past experiences

• Assumptions about what usually happens

• Stereotypes & beliefs about crime & criminals

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Anxiety/Shock Age

Individual differences

Time delay

Consequences

Leading questions

Factors that affect EWT

Leading questions:This is a question that contains hints about what the right/desired answer should be.

• Key study: Loftus and Palmer 1974

Aims

• Loftus and Palmer’s experiment was actually two experiments.

• They wanted to investigate in general how accurate or inaccurate memory was. Specifically they wanted to see the effect of leading questions upon estimates of speed.

Aims

• Experiment 1 – See if the speed estimates would be

influenced by the wording of the question asked.

– Hit vs Smashed

Aims

• Experiment 2 – To see if the leading questions just

changed the responses given to the questions, or whether the participant’s memories had actually altered as a result of the leading questions.

Procedures

• Type of study: Laboratory experiments

• See hand out of Loftus and Palmer 1974

Task

• Find a clip of an incident (download so it can be played).

• Formulate four questions about the event, one of these must be a leading question.

Other factors that affect EWT

Interested in Loftus?

• Find out more:

http://faculty.washington.edu/eloftus/

Practical applications

• In the UK, the Devlin Report (1976) recommended that that no jury should convict on the evidence of a single eyewitness testimony alone. Barristers are also not allowed to aske leading questions for fear of generating false testimonies.

• In the USA (1990’s) the “Innocence project” has helped to overturn the wrongful convictions through faulty EWT of 220 men (by 2008).