2.4 - Eyewitness Testimony Flashcards
Eye witness testimony
When a person who was present at a event recalls what happened
Relies on recall from memory
Can be inaccurate or distorted
Factors that affect accuracy of eye witness testimony
- misleading information
- anxiety
- age of the witness
Loftus & palmer (1974)
Misleading information
Conducted two experiments
Experiment 1 :
- shown a film of multiple car crashes
- asked series of questions eg. How fast do you think the car was going when they got hit
- in different conditions the word hit was replaced with “smashed” or “ contracted “ etc.
Experiment 2 :
- participants split into 3 groups
- 1 group given the word smashed another hit and the 3rd control group wasn’t given any indication of the vehicle’s speed
- 1 week later the participants were asked if they’d seen any broken glass ?
Results of loftus and palmer
Results 1:
- participants that were given the word smashed estimated a higher speed
- participants given the word contracted gave lower speeds
Results 2 :
- even though there was no broken glass
- participants were more likely to say that they’d seen broken glass in the smashed condition than any other
Conclusion of Loftus & Palmer
Leading questions can affect the accuracy of peoples memories of an event
Evaluation points for Loftus & Palmer study
- implications for questions in police interviews
- artificial experiment - watching a video that is not emotionally arousing as a real life event which potentially affects recall
- leading questions give participants Ques about the nature of the experiment
- reduced the validity and reliability of the experiment
Loftus & Zanni looked into leading questions study - aim of study
How altering the wording of a question can produce a leading question that can distort EWT
Loftus & Zanni method
- shown a film of a car crash
- asked “ did you see THE broken headlight” “ did you see A broken headlight”
There was no broken headlight in the film
Loftus & Zanni results
- 17% of those asked about “The” broken headlight claimed they saw one
- 7% of the group asked about “ a” broken headlight
Loftus & Zanni conclusion
Simple use of the word “ THE” is enough to affect the accuracy of peoples memory of an event
Loftus & Zanni evaluation
- lab study which made it possible to control any extraneous variables ✅
- possible to establish cause and effect ✅
- artificial study so thus lacked ecological validity ❌
What else can affect the accuracy of recall ?
Post event discussion
Shaw et al. Method
- paired participants with a confederate
- pairs were shown videos of a staged robbery and were interviewed together afterwards
- participant and confederate alternated who answered the questions first
Shaw et al. Results
- participant responded first = recall was accurate 58% of the time
- confederate answered first and gave accurate answers the recall of the participants was 67%
- if confederate gave inaccurate answers = correct recall for participants fell to 42%
Age of witness Valentine and Coxon Method :
- 3 groups ( children, young adults, elderly ) watched a kidnapping video
- asked a series of leading and non leading questions about what they’ve seen
-
Valentine and Coxon results
- elderly and children gave more incorrect answers to non leading questions
- children were mislead more by leading questions compared to adults and elderly
Valentine and Coxon evaluation
- implications in law when elderly and young children are questioned
- artificial experiment wasn’t as emotionally arousing as s real life situation thus lacks ecological validity
Anxiety
- small increases in anxiety and arousal = increase the accuracy of memory
- high levels = negative effect on accuracy
- violent crimes where anxiety increases the witness may focus on central details eg. Weapon and neglect other peripheral details eg. What the criminal was wearing ?
Loftus - weapon focus in EWT method :
- study with independent groups design participants heard discussion in a nearby room
- 1 condition = a man came out of the room with a pen and grease on his hands
- 2nd condition = the man came out carrying a knife covered in blood
- participants were asked to identify the man from the 50 photographs
Lofus - weapon focus in EWT results
- Participants in Condition 1 were 49% accurate
- 33% of the participants in condition 2 were correct
Loftus - conclusion
When anxious and aroused witness focused on a weapon at the expense of other details
Loftus evaluation - weapon focus in EWT
- study has high ecological validity as the participants weren’t aware that the study was staged
- thus means that there are also ethical considerations as participants could have been very distressed at the sight of the man with the knife
Evidence against : misleading questions and anxiety don’t always affect EWT
- field study by YUILLE and CUTSHALL showed that witnesses of a real incident ( gun shooting ) has remarkably accurate memories of the event
- a thief was shot and killed by police and witnesses were interviewed
- 13 were invited to be re- interviewed 5 months later
- recall was highly accurate even after the time period
- researchers had included two misleading questions but these had no effect on the subjects answers
- study had high ecological validity as it was based on real life event
- the witnesses who experienced the highest levels of stress were also closest to the event - it’s difficult to determine whether proximity or stress contributed to the accuracy of recall
Cognitive interview
A questioning technique used by the police to enhance retrieval of information from the witnesses memory
- important role within the legal system and the serious repercussions when it goes wrong
Context reinstatement
- recreating a mental picture of the event including both the external environment and the individuals own internal state
- recalling the context in this way may provide cues that help trigger memories
Recall from different perspective
- recreating the event from another’s persons perspective
- may increase the accuracy of the testimony by reducing the effect of the witness schema
Recall in different chronological order
- recreating the event In a different sequence in time
- recalling the event in a different order may also increase the accuracy of the testimony by reducing the effect of the witness schema
Report everything
- The witness is encouraged to report all details of the event even if they may seem irrelevant or unimportant
- memories often have many different retrieval paths recalling other details may provide cues that help trigger further memories
Geiselmam et al. ( the effect of the cognitive interview ) method
- in a staged situation an intruder carrying a blue rucksack entered a classroom and stole a slider projector
- 2 days later participants were questioned about the event
- study used independent groups design
- participants were either questioned using a standard interview procedure or the cognitive interview technique
- early in the questioning the participants were asked “ was the guy with the green backpack nervous “
Later in the interview the participants were asked what colour the man’s rucksack was
Geiselman et al. Results & conclusion
Results:
- participants in the cognitive interview condition were less likely to recall the rucksack as being green than those in the standard interview condition
Conclusion :
The cognitive interview technique reduces the effect of leading questions
Geiselman et al. Evaluation
- experiment was conducted as though a real crime had taken place in the classroom - high ecological validity
- experiment used independent group design - participants in the cognitive interview condition could have been naturally less susceptible to leading questions than the other group
Post-event discussion
- Occurs when there is more than one witness to an event
- witnesses may discuss what they have seen with other Co-witnesses
- this effects accuracy
Tunnel theory
Explanation for the weapon-focus effect is that the weapon narrows the field of attention and thus reduced information to be stored
Why is the cognitive interview important ?
- improving effectiveness of questioning witnesses in police interviews
- applying findings of psychological findings to this area
First component of the cognitive interview
Report everything you can recall even if it seems trivial
