Accuracy of the Eye-witness Testimony Flashcards
What 2 factors affect the accuracy of the Eye-Witness Testimony?
Misleading information
Anxiety
What is the Eye-Witness Testimony (EWT)?
The ability of people to remember the details of events that they themselves have observed
What are the 2 types of misleading information?
Leading questions
Post-event discussion
What is the main study into leading questions?
Loftus & Palmer (1974)
45 students shown a video of a car accident
Participants asked how fast car was going when they hit each other - verb hit replaced
Contacted = mean estimate of 32mph
Smashed - mean estimate of 40.5mph
What are the 2 reason why leading questions affect EWT?
Response bias explanation
Substitution explanation
What is the response bias explanation?
Suggests the wording has no real affect on memory but affects how the participants answer
What is the substitution explanation?
The wording alters the participant’s memory
How is the substitution explanation supported?
Loftus & Palmer (1974) - broken glass
Loftus & Zanni (1975) - headlight
What did Loftus and Palmer find which supports the substitution explanation?
Participants who heard smashed were more likely to report that they saw broken glass as suppose the the verb “hit” (no broken glass)
What did Loftus & Zanni do (1975)?
7% participants said they saw “a” broken headlight
17% participants said they saw “the” broken headlight
How does post-event discussion affect the accuracy of EWT?
Memory contamination
Memory conformity
What is memory contamination?
When discussion causes the memories to be altered with information that may not be true
What is memory conformity?
When witnesses go along with each other’s points as they want social approval but their memory remains the same
What did Gabbert et al (2003) find about post-event discussion?
Participants tested individually or in pairs
The pairs were told they watched the same video when it was different perspectives
71% of participants that were in pairs recalled information they didn’t see (as suppose to 0%)
What are the strengths of misleading information?
Good control of variables in lab studies
Studies can be replicated to test reliability
Important applications to real life
Shows that co-witnesses should be prevent from discussing the event
How was there good control of variables in the lab studies for misleading information?
Extraneous variables such as weather were removed
How can the lab studies for misleading information be replicated to test reliability?
Loftus & Palmer + Loftus & Zanni’s experiments were carried out under the exact same procedures - can conclude the iv itself affect the dv
How does misleading information have important application to real life?
Police are careful with how they word questions when interviewing witnesses to avoid substitution
How does misleading information show that co-witnesses should be prevented from discussing the event?
Gabbert’s study shows that people change their answers when speaking about their testimony with another witness
What did Bodner et al (2009) find?
Can reduce effects of post-event discussion if participants are warned of impact
What are the weaknesses of misleading information?
Lab studies lack ecological validity
Yuille & Cutshall (1986) - counter research
Lack of population validity
How did the lab studies supporting misleading information lack ecological validity?
Watching video isn’t actually experiencing it
Staged event doesn’t cause anxiety - can affect accuracy
EWT has real consequences in real life
Demand characteristics
What did Yuille & Cutshall do?
Performed ecologically valid experiment where they interviewed 13 witnesses of a real crime
Participants asked leading questions which had no effect on recall accuracy
How do the lab studies supporting misleading information lack population validity?
Many of the experiments which Loftus did involved students which is not a representative sample so we cannot generalise the findings
What did Yerkes & Dodson suggest about anxiety’s affect on EWT?
The relationship is an inverted u, performance will increase with stress only up to a certain point
What did Deffenbacher find about anxiety’s affect on EWT?
Reviewed 21 studies on the effects of anxiety on EWT
10 linked higher arousal to increased accuracy
11 linked lower anxiety to lower accuracy
What did Loftus & Burns (1982) find about anxiety?
Participants allocated to 1 of 2 conditions
Watch violent film - boy shot in head
Watch non-violent film of a crime
Participants less accurate in the violent short film than the participants who watched the other film
HIGH ANXIETY CAUSES LOW RECALL ACCURACY
What is the weapon focus effect?
The anxiety levels of observers increase when a weapon is pulled out, also causing them to fixate on the weapon
What did Johnson & Scott (1976) find about the weapon focus effect?
Participants sat outside a lab and heard 1 of 2 conditions
1. Friendly convo with man carrying pen with grease on his hands
2. Argument, smashing glass, overturned furniture and a man emerging with blood-stained paper knife
Witnesses had to identify the man from 50 photos
49% accurate identifying man with the pen
33% accurate identifying the man with the knife
What did Stelbay (1992) find about the weapon focus effect?
Performed meta-analysis and found a variety of cases which included the presence of a weapon that signifies reduced the accuracy of identifying the person holding it
What 2 studies show positive examples of high anxiety?
Christianson & Hubinette (1993) - bank robbery
Yuille & Cutshall (1986) - armed robbery in Canada
What did Christianson & Hubinette’s (1993) study find?
Question 58 real witnesses to a bank robbery
Participants were either victims or bystanders
The victims (more anxious) had better and more accurate recall
What did Yuille & Cutshall (1986) find?
Witnesses who had been the most anxious during an armed robbery gave the most accurate account
What are the weaknesses of anxiety as a factor affecting EWT?
Weapon-focus effect may not be caused by anxiety - Pickel (1998)
Field studies sometimes lack control
Ethical issues
Yerkes Dodson Law too simplistic
Individual differences
How might the weapon focus effect not be caused by anxiety?
Pickel (1998)
Suggested low accuracy may be due to surprise rather than accuracy
He had 4 conditions which had high/low elements of surprise and threat
The conditions with higher surprise caused identification to be less accurate than the high threat conditions
How might field studies lack control (anxiety)?
Extraneous variables may have affected the results
People with higher anxiety may have been closer which is why they may have been more accurate than the
How are there ethical issues during the studies on anxiety?
Creating anxiety in people is unethical itself
In Johnson & Scott’s study, the participants may have been psychologically harmed when witnessing the bloodied knife and there was deception
How is the Yerkes Dodson Law too simplistic?
Anxiety is difficult to define and measure accurately
Anxiety can be due to worry and everyday stresses
How do individual differences affect anxiety?
A person’s personality may affect their recall rather than anxiety
Bothwell et al (1987)
Neurotic individuals less accurate with higher stress than stable individuals
