3. COLLECTING EVIDENCE Flashcards
Recognising E-fit faces
Bruce aim
See if there was a difference in our ability to recognise internal and external features of facial composites
Facial composites of celebrities
Bruce method
Lab
Bruce sample
Self selected
30 staff and students from Stirling Uni (M+F)
Bruce design
Independent 3 conditions: 1. internal + external 2. internal 3. external Given ten photos of celebs (targets) Match 40 composite images (4 for each target)
Results from Bruce
No significant difference in accuracy between complete composite and external factors only (35% correct)
Internal factors not so accurate- 19.5% correct
What do Bruces findings suggest
When witnesses are recalling internal features, we may not be able to trust accuracy
Pros of Bruce
Lab= increased control Independent- reduces DC Standardised- replicable Quantitative Useful applications
Cons of Bruce
Small sample- reduced population validity
Reduced ecological validity- no consequences
Reduced task validity- using celebrities
False confession
Kassin aim
Whether psychologically vulnerable people are more likely to make a false confession
Kassin sample and design
79 undergraduates
Independent
Deceived into thinking the experiment was on reaction time
Voluntary confession
No external pressure
Coerced compliant confession
Had enough of questioning so confess
Coerced internalisation confession
Persuaded that you committed a crime
Kassin procedure
Ps tested individually with confederate
Told letters to type on computer- specifically told not to press ALT key, as it will ‘crash’ the computer
3 minted of pressing keys
Experimenter accuses P of pressing ALT key, confederate said they did when they didn’t (pressure)
4 conditions for Kassin
- high vulnerability- 67 letters per minute, accused of pressing ALT
- high vulnerability- 67 letters, not accused
- low vulnerability- slow, 43 letters per min, accused
- low vulnerability- 43/min, not accused