factors influencing eye witness testimony: reliability Flashcards
define eye witness testimony (ewt)
an account of an event or crime that was seen by an observer ‘first hand’. Although useful to the police, they can be unreliable.
how does reconstructive memory affect how we retain information ?
- human memory is reconstructive
- memory does not record events in exact detail
- instead, it fits memories within pre-existing frameworks of expectations and past knowledge (schema)
how does reconstructive memory affect EWT and what did Bartlett call this ?
a person’s ability to recall a crime may be based more on their schema of the event than on what actually occurred - Bartlett called this ‘effort after meaning’
what is a leading question ?
a form of post-event information that triggers schemas
what does a leading question do ?
it suggests a particular answer because of the way it is phrased and may point an eye witness towards a specific answer
what is the potential result of asking an eye witness a leading question ?
the witness may incorrectly access the information provided in the first question, rather than what they actually remember
what is the influence of anxiety of EWT ?
witnessing a dramatic event creates stress and anxiety which may affect the person’s ability to register and recall the event
what did Deffenbacher (1983) do ?
they reviewed 21 studies
what did deffenbacher (1983) find ?
- moderate anxiety helps memory (like an athlete produces their best performance when they are ‘pumped up’ before a crowd)
- if an eye witness’ anxiety continues to rise (and becomes extreme), this creates a decline in recall.
what can weapon focus do ?
weapon focus is one way that anxiety is pushed ‘over the edge’
what is the potential effect of weapon focus ?
- in violent crimes when the perpetrator is carrying a weapon, the brain’s natural tendency is to zoom in on that as the main source of stress
- so an eye-witness’ recall is relatively poor and other important details are not noticed or are distorted
what is weapon focus explained by ?
tunnel theory
- presence of a weapon leads to selective attention
- this excludes or ignores competing bits of information
what is the strength of leading questions (supporting evidence) ?
Loftus and Palmer (1974)
- ppts who heard ‘smashed’ gave higher estimates.
- those hearing ‘smashed’ in the follow-up study were more likely to claim that they saw broken glass
what does Loftus and Palmer (1974) suggest ?
post-event information in the form of leading questions has a significant effect on recall
what is a weakness of leading questions and weapon focus ?
evidence from real-life crimes is contradictory
- Yuille and Cutshall (1986) assessed recall of 13 witnesses to a real-life shooting who rated themselves as very anxious at the time
what were the findings of Yuille and Cutshall (1986) ?
- about 5 months after the event, the witnesses produced accurate accounts of what happened despite researchers including two leading questions in this second interview
what does Yuille and Cutshall (1986) suggest ?
suggests that the effects of leading questions and weapon focus may be less pronounced when applied to real-life events
what is a strength of weapon focus ?
supporting evidence
- Johnson and Scott (1976)
what did Johnson and Scott (1976) do ?
arranged half their ppts to overhear an argument and see a man with greasy hands carrying a pen (control). the other half saw a man with a blood-stained knife (experimental condition).
what were the findings of Johnson and Scott (1976) ?
49% of control later correctly identified the man (from 50 photos) compared to 33% in the experimental condition - the ppts were not aware they were being observed and so there was high ecological validity
what does Johnson and Scott (1976) suggest ?
suggests that ppts’ attention had been drawn towards the weapon and away from other peripheral details like facial features
what is the competing argument to Johnson and Scott (1976)
- pickel (1998) founder similar effect when a man pulled out a raw chicken or a Pillsbury Dough Boy to pay a cashier, rather than presenting his wallet.
what does pickel (1998) suggest ?
suggests that ‘weapon focus’ is related to surprise as much as anxiety
what is an application of EWT research ?
EWT research has led to the introduction of SOCIAL FRAMEWORK EVIDENCE.
what is social framework evidence ?
in US courts, psychologists may be called to provide some ‘context’ to juries - often in the form of relevant psychological evidence that demonstrates the unreliability of such testimony
what does the application suggest ?
this suggests that research which recognises the fallibility if human memory is useful in reducing miscarriages of justice in legal cases
