factors affecting accuracy of EWT: anxiety Flashcards
1
Q
how can anxiety have a negative effect on recall?
A
- presence of a weapon creates anxiety
- this leads to focus on the weapon, reducing a witness’s recall for other details of the event
2
Q
describe the procedure for research johnson and scott (1976) did on weapon focus
A
- pps believed they were taking part in a lab study
- while seated in a waiting room, pts in the low-anxiety condition heard a casual conversation in the next room then saw a man walk past them carrying a pen with grease on his hands
- pts in the high-anxiety condition overheard a heated argument, with the sound of breaking glass. a man walked out of the room, holding a knife covered in blood
3
Q
describe the findings for research johnson and scott (1976) did on weapon focus
A
- pts later picked out the man from a set of 50 photos
- 49% who had seen the man carrying the pen were able to identify him
- 33% for those who had seen man holding blood-covered knife
4
Q
describe the conclusion / explanation for research johnson and scott (1976) did on weapon focus
A
- tunnel theory of memory argues that people have enhanced memory for central
- weapon focus as a result of anxiety can have this effect
5
Q
how can anxiety have a positive effect on recall?
A
- witnessing a stressful event creates anxiety through physiological arousal within the body
- flight or fight response is triggered, increasing alterness
- this may improve memory for the event as we become more aware of cues in the situation
6
Q
describe the procedure for research yuille and cutshall (1986)
A
- conducted a study of an actual shooting in a gun shop in canada
- shop owner shot a thief dead
- 13/21 witnesses took part in the study
- they were interviewed 4-5 months after the incident and these interviews were compared with orginial police reviews at the time of the shooting
- accuracy was determined by the number of details reported in each account
- they were also askeed to rate how stressed they had felt at the time of the incident on a 7-point scale and whether they had any emtoional problems since the event (eg. sleepnessness)
7
Q
describe the findings and conclusion for research yuille and cutshall (1986) did
A
- witnesses were very accurate in their accounts
- there was little change in the amount recalled or accuracy after 5 months
- some details were less accurate eg. recollection of items and age / height / weight estimates
- pts who reported highest stress level were more accurate than less-stressed group (88% vs. 75)
- this suggests that anxiety does not have a detrimental effect on the accuracy of EW memory in a real-world context and may even enhance it
8
Q
what is the inverted-U theory?
A
- states that performance will increase with stress, but only to a certain point, where it decreases drastically
- yerkes and dodson (1908) suggested that the relationship between emotional arousal and performance looks like an ‘inverted U’
9
Q
how did deffenbacher (1983) explain the contradictory findings?
A
- he reviewed 21 studies of EWT and found contradictory findings on the effects of anxiety
- used yerkes-dodson law to explain findings
- when we witness a crime / accident, we become emtionally and physically aroused
> emotional change = anxiety, physiological change = fight or flight response - lower levels of anxiety / arousal produce lower levels of recall accuracy, then memory becomes more accurate as level of anxiety / arousal increases
- however, there is an optimal level of anxiety, which is the point of maximum accuracy
- if a person experiences any more arousal, their recall suffers a drastic decline
10
Q
how should the inverted-U theory be properly tested?
A
- many lab-based and real-world studies of anxiety only compare high and low anxiety roups
- moderate anxiety group needs to be tested as well
11
Q
how did parker et al. (2006) properly test the inverted-U theory?
A
- interviewed people who had been affected by hurricane andrew in the US in 1992
- researchers defined anxiety in terms of amount of damage pps suffered to their homes
- researchers found there was a link between level of recall and amount of damage / anxiety experience
12
Q
evaluation: johnson and scott may not have tested anxiety
A
- pps could have focused on weapon because they were surprised at what they saw, rather than scared
- pickel (1998) conducted an experiment using scissors, a handgun, a wallet or a raw chicken as the hand-held items in a hairdressing salon video (scissors = high anxiety, low unusualness)
- EW accuracy was significantly poorer in high unusualness conditions (chicken and handgun)
- this suggests that weapon focus effect is due to unusualness rather than anxiety / threat and therefore tells us nothing specifically about the effects of anxiety on EWT
13
Q
evaluation: evidence supporting the view that anxiety has a negative effect on accuracy of recall
A
- valentine and mesout (2009) study supports research on weapon focus, finding negative effects on recall
- researchers used objective measure (heart rate) to divide pps into high- and low- anxiety groups
- 17% of high-anxiety group correctly identified actor in london dungeoun’s labyrinth in a line-up vs. 75% correct identification for low-anxiety group
- this suggests that a high level of anxiety does have a negative effect on the immediate EW recall of a stressful event
14
Q
evaluation: evidence showing that anxiety can have positive effects on accuracy of recall
A
- christianson and hubinette (1993) interviewed 58 witnesses to actual bank robberies in sweden
- some witnesses were directly involved (eg. bank workers) and some were indirectly involved (eg. bystanders)
- researchers assumed that those directly involved would experience the most anxiety
- recall was >75% accurate across all witnesses
- direct victims (most anxious) were even more accurate
- these findings from actual crimes confirm that anxiety does not reduce the accuracy of recall for eyewitnesses and may even enhance it
15
Q
evaluation: christianson and hubinette study has low internal validity
A
- they interviewed their pts several (4-15) months after the event
- therefore, they had not control over what happened to their participants in the intervening time (eg. PED)
- effect of anxiety may hve been overwhelmed by these other factors and impossible to access by the time the participants were interviewed
- therefore, it is possible that a lack of control over confounding variables may be responsible for these findings, invalidating their support
