6.1.7 Factors affecting EWT Flashcards
What is an eye witness testimony?
Where a witness describes what they saw at during an event or crime, they may need to present in court
Using research, demonstrate the importance of eye witness testimony in court cases.
- 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
List the 3 factors that may affect the trustworthiness of EWT.
1) Stress and arousal
2) Post-event information
- Misinformation
- Reconstructive mem
- Leading Q’s
3) Weapon focus
Describe stress and arousal as a factor affecting reliability of EWT.
- 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. As arousal incr, mem accuracy improves, but after optimum is reached, arousal will continue to incr but mem accuracy will decr
- Eg trauma experienced by EWTs from crime may lead to optimum stress arousal when recalling but then mem accuracy will decr
EACH- S/W E (stress & arousal)
1) 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 in identifying the perpetrator
E - This supports stress as a factor as it provides evidence for Yerkes-Dodson law, the memory recall of EWs was less accurate bc of over-arousal from the London Dungeons jumpscare, suggesting that the emotional state of an EW is a factor affecting accuracy of recall in EWT
2) P - Yuille and Cutshall (1986) reject this theory
E - They found that EWs w higher lvls of arousal = more accuracte in recall of real incident
E- Supports, Yuille and Cuthsall has high ext V due to evaluating real-life EW recall w factor of stress, demonstrates arousal/stress isn’t a factor affecting EWT, EWT= reliable
EACH-A (stress & arousal)
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
EACH-C (stress & 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
EACH-H (stress & arousal)
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
Describe post-event information as a factor affecting reliability of EWT.
- Post-event info >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 eg other EWs, media, police
- ## Reconstructive mem >Info remembered can be changed due to confabulation/ rationalisation of events that don’t conform to an individuals schema eg.Ews fill in gaps w info from their schemas that makes sense to them, often comes through leading Q’s
EACH- 2S/1W E (Post event)
1)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, EWs may change info from crime witnessed if it doesn’t fit into their schemas
2)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, can lead to deception!! decr reliability of EWT
1)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
EACH-A (post event)
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
EACH- C (post event)
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
EACH- H (post event)
1) 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
2) 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
Describe weapon focus as a factor affecting reliability of EWT.
- 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 mem accuracy will decr
EACH- 2S E (weapons focus)
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, decr the reliability of EWT due to weapons focus
P - Pickel (1998) supports
E - Found that ppts who saw a video of a man walking into a hair salon with conditions of handgun or raw chicken showed the poorest memory recall
E - This supports the idea that a weapon will lead to over-arousal of stress eg handgun, under-arousal eg raw chicken and so under-performance of memory recall due to going over or not reaching optimum stress level
