Y2: Psychology: Criminal: Factors Influencing the Reliability of EWT

Where witnesses describe what they saw during the accident or crime whereby they may need to attend court however the account may not be as accurate.

Wells et al (1998) - found 40 cases where DNA evidence showed that none of the convicted criminals could have been the true offender
Wright and McDaid (1996) - found that in 20% of identity parade line-ups the witnesses identified the foil

1) Stress and arousal
2) Post-event information
3) Weapon focus

• Witnesses are placed under stress when witnessing an event

• Yerkes-Dodson Law states that there is an optimum level of stress arousal in a situation that leads to the best memory performance

• Therefore there are also levels of being under-aroused and over-aroused that will lead to an under-performance in memory

P - Valentine and Mesout (2009) support
E - They found that when ppts were scared in the London Dungeons they showed high levels of anxiety which reduced their accuracy to identify the perpetrator
E - This therefore suggests that the emotional state of the witness effects memory accuracy
P - Yuille and Cutshall (1986) reject this theory
E - They found that when interviewing

P - Valentine and Mesout (2009) had high ecological validity
E - It took place in a natural setting whereby ppts weren’t aware they were in a study
E - Meaning that findings would be accurate to stress affecting EWT in a real life situation

P - Yes
E - It suggests that when gathering EWT accounts the police should also measure their stress level
E - However this can be limited as it doesn’t suggest ways to improve the accuracy due to not being able to advise people to reach the optimum level of arousal

P - Flashbulb memory can be used as an alternative explanation
E - It states that a memory with high levels of stress due to significance will be remembered accurately in a lot of detail
E - Therefore it suggests that if you are very stressed you will remember everything in detail due to its impact
P - Arousal is difficult to operationalise
E - It can result from anxiety or fear or increased alertness
E - Therefore this makes comparisons difficult due to having inconsistent definers for arousal

• Witnesses are often interviewed over a period of time after the event in which they may be exposed to information they did not already have

• It can arise in the form of leading questions and schemas coming from sources of other witnesses, the media, or the police themselves

• Information remembered can be changed due to confabulation/rationalisation of events that don’t conform to an individuals schema

• Information remembered can also be changed through leading questions that may suggest something being there when a witness does not remember it so they will assume they forgot and answer as if they remembered that something happening

P - Bartlett (1932) supports
E - He found that when ppts recalled an unfamiliar story of ‘War of the Ghosts’ they changed details (such as someone dying at sunset instead of sunrise) through confabulation or rationalisation to fit their schema
E - Therefore this supports the idea that our schemas will change our memory of something to make it make sense
P - Loftus and Palmer (1974) supports
E - They found that when asking ppts how fast a car was going, ppts were more likely to estimate higher speeds with “smashed” as opposed to “contacted”
E - Therefore showing that using a leading question will suggest to the witness something is different than what they remembered and so they will assume they forgot or got it wrong

P - Yuille and Cutshall (1986) reject
E - They found that when interviewing witnesses 5 months after the crime using leading questions they still recalled events accurately
E - Therefore refuting the idea that post-event information will alter a witnesses memory

P - Lab research lacks ecological validity
E - It assesses EWT in artificial, controlled conditions such as Loftus and Palmer (1974) asking ppts to watch a video
E - This does not reflect real life situations whereby witnesses will not already be focused on the event
P - High levels of control over EVs
E - This is problematic due to real life cases involving EVs that would affect what a witness remembers and how well
E - Therefore highly controlled experiments do not reflect what is remembered and how well in real life due to factors such as attention affecting it

P - Yes
E - It suggests that when gathering EWT accounts the police should avoid leading questions and post-event info
E - Therefore accounts will be more reliable and techniques such as the cognitive interview use these methods to ensure a detailed accurate account

P - Flashbulb memory can be used as an alternative explanation
E - It states that a memory with high levels of stress due to significance will be remembered accurately in a lot of detail
E - Therefore it suggests that if you are very stressed you will remember everything in detail due to its impact

• If there is a weapon present at a crime then witnesses will focus attention on that

• Attentional narrowing leaves no attention for things happening in a witnesses peripheral vision where valuable parts of the crime may be taking place

• Yerkes-Dodson Law can explain this through stress arousal whereby the presence of a weapon may lead to over-arousal and so memory performance will be bad

P - Loftus (1979) supports
E - Found that only 33% of ppts who witnesses a staged crime whereby a knife was involved accurately identified the offender
E - This suggests that weapon focus reduces our ability to remember details of the offender due to attentional narrowing
P - Pickel (1998) supports
E - Found that ppts who saw a video of a man walking into a hair salon with a handgun or raw chicken showed the poorest memory recall
E - This supports the idea that a weapon will lead to over-arousal of stress and so under-performance of memory recall and the raw chicken led to under-arousal

P - Wagstaff (2003)
E - Found that when comparing witness interviews with police description of suspect there was no evidence of any effect of weapon presence on accuracy
E - Therefore refuting the idea that the presence of a weapon distorts accuracy of memory due to stress or attentional narrowing

P - Much research is lab-based
E - They tend to reduce ppts engagement due to them knowing they are in a study
E - Therefore they will be less emotionally invested and will pay less attention due to it not affecting them in real life, not accurately reflecting what would happen during a real crime

P - Yes
E - It states that if there is a weapon present the witness will focus their attention on that and become very stressed
E - Therefore police need to take this into account when interviewing

P - Flashbulb memory can be used as an alternative explanation
E - It states that a memory with high levels of stress due to significance will be remembered accurately in a lot of detail