factors affecting EWT

Question 1

innocence project 2015

Answer 1

eyewitness misindentification in 75% of cases
police may subconsciously provide positive reinforcers for wrong answers and memory can be distorted

Question 2

post-event info

Answer 2

anything seen after crime influences memory

Question 3

misinformation

Answer 3

tendency of post-event info to interfere with memory
- confabulation as blanks filled in
- recency effect
- poor encoding leads to distortion

Question 4

schemas and reconstructive memory

Answer 4

Bartlett’s war of ghosts
- distortion
- simplification
- rationalisation
- transformation (adjusting order of events in terms of intensity so non-chronological)

Question 5

leading questions

Answer 5

contains info previously unknown to witness

Question 6

Gabbert

Answer 6

showed pairs of ppts a video of the same crime each from slightly different angles
each pair then discussed what they’d seen then tested on recall individually
found that 7.1% of the ppts referred to details their partner had mentioned
no examples of this in non-discussion control

Question 7

Koriat and Goldsmith

Answer 7

oppose post-event info as some ppts felt they had to give an answer even if they didn’t have one

Question 8

weapon focus

Answer 8

an eyewitness will focus more of their stress and attention on an object that can cause them harm during the crime than the offender

Question 9

Johnson and Scott

Answer 9

at Uni of Michigan ppts were left in waiting room outside lab
half of ppts overheard quiet conversation about equipment failure and saw man come out of lab holding a pen and covered in grease
other half heard argument in lab, breaking glass then bad came out with knife covered in blood
given 50 photos and asked to choose the man they’d seen, 49% of pen group chose correctly compared to 33% in knife group

Question 10

yerkes-dodson law

Answer 10

increase in arousal improves performance but only up to a point
arousal state caused by a weapon is often past optimum so they only remember central detail (weapon) not details

Question 11

Pickel

Answer 11

ppts watched 2 min video of hair salon where a man walks in an the receptionist hands him money
each of the 5 groups saw a different object being held by the man = nothing, scissors, handgun, wallet, chicken
after 10 mins they filled in questionnaire and asked to describe him

no diff in accuracy of descriptions but eyewitness accuracy was poorer in high unusualness conditions

Question 12

Yuille and Cutshall

Answer 12

21 eyewitnesses interviewed by police, 20 contacted 4 months after event, 13 agreed to take part in study
interviewed through same procedure as the original interview
half asked if they saw ‘a’ broken headlight, half asked if they saw ‘the’ broken headlight when there was none then had to rate stress at time of incident

leading questions had very little effect on recall, 10 said there was no broken headlight
ppts who said they had a higher level of arousal were more accurate in their recall of a real incident (gun shooting in Vancouver), so EWT is accurate in reality

Question 13

criminal key question

Answer 13

is EWT too unreliable to trust

Question 14

criminal practical

Answer 14

ppts watched 2 min long video of staged whodunnit
split in 2 groups - non-leading and leading questions
wrote down everything they could remember after then completed questionnaire
leading question was in middle of 5 questions
15 min distraction task
after task each group received same questionnaire of 5 questions, completed this and results collected - chi squared to test