Eyewitness testimony (booklet 5) Flashcards
(25 cards)
What is eyewitness testimony?
The ability of people to remember the details of events which they have observed
Name factors affecting the accuracy of eyewitness testimony
Misleading information- leading questions, post event discussion
Anxiety
Describe memory as a reconstructive process
Memories are not a simple replay of past events- they are reconstructions based on our experience
Means memories can be distorted so are not always accurate and reliable accounts
Name 2 types of misleading information
Leading questions
Post event discussion
What is a leading question?
A question that suggests a certain answer because of the way it was phrased
Describe Loftus and Palmer’s (1974) study of the effect of leading questions
Participants shown video of car crash
Asked “how fast were the cars going when they ____ each other”
Studies how verb choice affected mean speed estimate
Smashed=40.5mph
Contacted=31.8mph
Questioned again a week later - “did you see any broken glass”
There wasn’t any in video- found ‘smashed’ ps more likely to day yes than other conditions
Concluded wording of questions implied certain details leading to distorted recall- substitution explanation
Describe Loftus and Zanni’s (1975) study on the effects of leading questions
Ps shown video clips of car accident
Half asked ‘did you see a broken headlight’, other half asked ‘did you see the broken headlight’
There was no broken headlight in the video
‘A’ = 7% said yes ‘the’ = 17% said yes
Using ‘the’ suggested there was a broken headlight in the video distorting their recall
Describe the response bias explanation
Suggests wording of question had no effect on participants memories but influences how they answer
Evaluate effect of leading questions- research control
Supporting studies are lab based
Allows control of variables to show clear link between use of leading questions and incorrect recall
However artificial task used- video doesn’t come with real emotions in that situation and it’s rare you observe whole event
Lacks ecological validity
Evaluate effect of leading questions- real world application
Has important real world application
Influences how police may do their questioning
Reduces inaccuracies or bias in eyewitness testimony
Evaluate effect of leading questions- evidence against substitution
EWT is more accurate for some aspects of event than others
Sutherland and Hayne (2001) showed participants a video then asked purposefully misleading questions
Recall more accurate for central details than peripheral ones
Central details relatively resistant to distortion by misleading information- not predicted by substitution explanation
What is post event discussion?
A potential source of misleading information where witnesses discuss what they saw after an event
Can affect accuracy of their accounts
Describe a study supporting post event discussion as a form of misleading information
Gabbert et al (2003)
Sample of 60 students and 60 older adults
Participants watched a video of a girl stealing
Either tested individually (control group) or in pairs (co witness group)
Participants told had watched same video when actually slightly different-only one perspective saw girl actually steal
Only participants in co witness group discussed
Then all ps completed a questionnaire testing their memory of event
71% of cowitness group recalled info they hadn’t seen
60% said girl was guilty despite not actually seeing her commit a crime
Highlights issue of post event discusssion and powerful effect on accuracy of eyewitness testimony
Describe memory contamination
When discussing a crime, witness EWT becomes altered or distorted
They combine misinformation from other witnesses with their own memories
Describe memory conformity
Witnesses often go along with each other either to win social approval or because they believe other witnesses are right - the actually memory is unchanged
Evaluate the effect of post event discussion- research control
Supporting studies are lab based
Allows control of variables to show clear link between post event discussion and accuracy of EWT
However artificial task- video doesn’t come with real emotions and it is unlikely you would witness a whole event
Lacks ecological validity
Evaluate effect of post event discussion- evidence challenging memory conformity
Limitation of memory conformity is that post event discussion actually alters EWT
Skagerberg and Wright (2008) showed participants two versions of same film clip
Then participants discussed clips in pairs- when questioned after often didn’t report what they saw or what they heard from other co witnesses but a blend of the two
Suggest memory is distorted through contamination rather than being a result of memory conformity
Define anxiety
A state of emotional arousal where a real or perceived threat triggers a feeling of apprehension or uncertainty- can affect the accuracy of recall of an event
Describe research showing anxiety has a negative effect on recall - Loftus and Burns (1982)
P’s shown violent film of crime involving a boy being shot in the head
P’s had significantly impaired/reduced recall of events leading up to shooting compared to p’s who watched a non violent video
Shows mental state of anxiety can impair physical and cognitive functioning which has a negative effect on memory
Describe research showing anxiety has a negative effect on recall - Johnson and Scott (1976)
P’s believed taking part in lab study
While seated in waiting room one group heard a casual conversation in next room and saw a man leave with a pen and grease on his hands
Other group heard a heated argument and glass breaking then saw a man leave with a knife covered in blood (high anxiety condition)
Participants had to pick out man from set of 50 photos- only a third (33%) from high anxiety condition could compared to half (49%) from control group
Demonstrates tunnel theory- anxiety narrows your attention to one aspect of a scene
Describe research showing anxiety has a positive effect on recall - Yuille and Cutshall (1986)
Study of 13 witnesses to an actual shooting
Interviewed 4-5 months after and compared to police interviews from when it happened
Accuracy determined by number of details reported
Also asked how stressed they were at the shooting (7 point scale)
Found that little changed in accuracy
Highest levels of stress showed highest accuracy - 88% compared to 75% for less stressed group
Shows anxiety doesn’t have a detrimental effect and may even enhance accuracy in real settings
Explain the contradictory findings on effects of anxiety on EWT accuracy
Yerkes and Dodson (1908) suggested relationship between anxiety level and EWT accuracy looked like an inverted U
Deffenbacher (1983) reviewed 21 studies of EWT and explained contradictory findings using Yerkes-Dobson law
As witnesses we become anxious
Lower anxiety levels produce lower accuracy levels
When anxiety increases accuracy reaches an optimum point before suffering a drastic decline
Evaluate the effect of anxiety on EWT - unusualness not anxiety
Limited by fact Johnson and Scott may not have tested anxiety
Participants may have been surprised at what they saw rather than scared
Pickel (1998) conducted an experiment using scissors, a handgun, a wallet and a raw chicken in a hairdressing salon video- eyewitness accuracy significantly poorer in high unusualness conditions (handgun and chicken)
Suggests weapon focus effect is not due to anxiety, therefore telling us nothing about effects of anxiety on EWT
Evaluate the effect of anxiety on EWT - support for negative effects
Evidence supporting anxiety having a negative effect on accuracy of recall
Valentine and Mesout (2009) found negative effect on recall
Used an objective measure (heart rate) to divide participants into high and low anxiety conditions- anxiety clearly disrupted P’s ability to recall details about actor in London Dungeon’s Labyrinth
Suggests anxiety does have a negative effect on immediate eyewitness recall
