factors affecting the accuracy of EWT - anxiety Flashcards
explain weapon focus
presence of weapon creates anxiety so they focus on weapon & reduces witnesses recall for other events
who researched how anxiety has a negative effect on recall - weapon focus
johnson & scott (1976)
describe the research for how anxiety has a negative effect on recall (weapon focus) - procedure
- ppts. believed they were taking part in a lab study
- while seated in waiting room, ppts. in low anxiety condition heard casual conversation & then saw a man walk past with a pen/grease on his hands
- while seated in waiting room, ppts. in high anxiety condition overheard a heated argument, alongside sound of breaking glass & a man walked out the room holding a knife covered in blood
describe the research for how anxiety has a negative effect on recall (weapon focus) - findings/conclusions
- ppts. later picked out the man from a set of 50 photos
–> 49% who’d saw the pen were able to identify him
–> 33% who’d saw the knife/blood were able to identify him - tunnel theory of memory argues people have an enhanced memory for central events –> weapon focus due to anxiety can have this effect
who researched how anxiety has a positive effect on recall
yuille & cutshall (1986)
describe the research for how anxiety has a positive effect on recall - procedure
- conducted study of actual shooting in a gun shop in vancouver, canada
- shop owner shot a thief dead
- there were 21 witnesses –> 13 participated in study
- interviewed 4-5 months after & these were compared to original police interviews at time of shooting
- accuracy was determined by no. of details reported in each account
- witnesses also asked to rate how stressed they felt on 7-point scale & if they’ve had emotional problems since event
describe the research for how anxiety has a positive effect on recall - findings/conclusion
- witnesses were very accurate in accounts & there was little change in amount recalled/accuracy after 5 months
- some details were less accurate eg. colour of items, age/height/weight estimates
- those who reported highest levels of stress = most accurate
- suggests anxiety doesn’t have a detrimental effect on accuracy of EWT in real-world context & may enhance it
explaining contradictory findings ^
- yerkes & dodson (1908) - relationship between emotional arousal & performance = ‘inverted U’
- deffenbacher (1983) reviewed 21 studies of EWT & noted contradictory findings on effects of anxiety
- used yerkes-dodson law to explain findings
explain the yerkes-dodson law
- when we witness a crime/accident = emotionally & physically aroused –> anxiety (emotional) & physiological changes (eg. fight or flight response)
- lower levels of anxiety/arousal = lower levels of recall accuracy –> becomes more accurate as anxiety increases
- however, there’s an optimal level of anxiety = max. accuracy
- any more arousal = recall suffers drastic decline
AO3 -) johnson & scott may not have tested anxiety
E:
- participants may have focused on weapon as surprised at what they saw not scared
- pickel (1998) conducted an experiment using scissors, a handgun, a wallet or a raw chicken as hand-held items in a hairdressing salon video
- EWT accuracy was significantly lower in high unusualness conditions (chicken/handgun)
T: weapon focus effect is due to unusualness not anxiety/threat & thus, tells us nothing specifically about effects of anxiety on EWT
AO3 +) evidence supporting view that anxiety has negative effect on recall
E:
- valentine & mesout (2009) supports weapon focus research which finds negative effects on recall
- researchers used objective measure (heart rate) to divide participants into high/low anxiety groups
- in the study, anxiety clearly disrupted participants ability to recall details about actor in london dungeon’s labyrinth
T: suggests high level of anxiety does have a negative effect on immediate EW recall from stressful event
AO3 +) evidence showing anxiety can have a positive effect on recall
-) researchers interviewed participants several months after (4-15 months)
E:
- christianson & hubinette (1993) interviewed 58 witnesses to actual bank robberies in sweden
- some were directly involved & some indirectly
- researchers assumed those directly involved would experience higher anxiety & it was found recall was more than 75% accurate across all witnesses
- direct victims were even more accurate
T: findings from actual crimes confirm that anxiety can have a positive effect & doesn’t reduce recall accuracy
HOWEVER:
P: christianson & hubinette interviewed their participants several months after (4-15 months).
- didn’t have any control over what happened to participants in intervening time
- effects of anxiety may have been overwhelmed by these factors & impossible to assess by the time the participants were interviewed
T: therefore, it is possible that a lack of control over confounding variables may be responsible for findings which invalidates their support
