Eyewitness ID System - complete Flashcards
What is the importance of Eyewitness ID?
Eyewitness testimonies can be used as evidence in criminal trials
Most persuasive factor for jurors when deciding guilt or innocence of suspect Most incriminating evidence aside from confession
Police more likely to pursue a case if they have an eyewitness and a jury can be persuaded by a witness
What errors occur in Eyewitness ID?
Wells et al (1998) report 40 cases involving men wrongfully convicted of rape and were later exonerated by DNA - 90% were based on ID errors
By 2003 more than 100 people exonerated - 75% victims of mistaken ID
Innocence Project
What factors influence eyewitness ID?
Wells, 1978
Estimator Variables - CJS cannot control for
System Variables - CJS does have control over
What examples are there of System Variables?
PACE Code D Construction Media Presentation Instructions Administration
What is PACE Code D ?
Codes of practice for the identification of persons by police officers
Annexes contain guidelines for the conduct of identification procedures
A - Video ID
B- ID parade
C- Group ID
What is the purpose of a line-up?
- A fair test of recognition for the witness
2. The line-up needs to protect an innocent suspect
Explain PACE Code D: Obtaining ID evidence
Consists of at least 8 people and suspect who resemble suspect (demographics)
What are the main functions of foils?
Luus and Wells, 1981
Distractors help identify witnesses who are pressured into choosing someone from the line-up
Help assure that the line-up is a test of recognition and not of recall
Unlikely that the witness will identify suspect through guessing strategies and deductive reasoning.
Known to be innocent
What is Foil Bias?
A line-up may be unfair biased or suggestive when one person stands out from the rest
The witness can pick them out irrespective of whether they were present at the scene of the crime
Give examples of Foil Bias
Ellison et al (1981) - Black suspect in all white line-up
Uriah Courtney case - Young girl abducted and assaulted, rescued by passer by and described offender. Witnesses picked out Courtney from line-up and was prosecuted based on testimony, sentenced to life. DNA proved innocence
What is the structure of a line-up?
1 suspect others are foils
How are foils selected?
Match to description - share main features based on witness description
But - people are not good at describing faces and multiple varying descriptions require multiple line-ups
Match to Suspect - Suspect physical appearance analysed and matched
But - subjective judgement
What is better MTD or MTS?
MTD better ID performance on TP line-ups and TA line-ups
BUT
Witnesses poor at describing faces (Lindsay et al 1994)
Description needs to be interpreted
Darling et al (2008) using police foils increases ecological validity but no sig diff in performance
Police favour MTS (Valentine et al, 2009)
How are line-ups measured for fairness?
Line up size - adequate number of appropriate foils
Nominal size - no. persons presented in line-up
Effective size - no. persons who are effective choice alternatives for a witness who has little information or memory about the actual offender or for a witness viewing a line up which the suspect is actually innocent
What types of line-up are there?
Live- costly in time and resources , witnesses unable to attend, suspect/foils play up
Photo - more control, more time for witnesses, less stressful BUT photos are static
Video- currently used, advantage of photo parade but with richness of movements
How does the line-up media affect the effectiveness?
Shapiro et al (1986) meta analysis on medium and ID performance - no sig. diff between video and live ID yet photos would lead to poorer performance
What is a simultaneous line-up?
The suspect and other line-up members are in view all at the same time - viewing one face with another
Wogalter et al (1993) - most commonly used in US
What are the issues with a simultaneous line-up?
Lindsay and Wells (1985) - high false ID especially when real suspect is absent
Pozzulo and Lindsay (1998) - high false ID rate for children and older adults
What is a sequential line-up?
Eyewitness views one line-up member at a time
What are the benefits of a sequential line-up?
Produces better results with adults than simultaneous line-up
Lindsay et al (1991) - reduce false ID rates from biased line-ups
Why does the sequential line-up produce better results?
Lindsay and Wells (1985) - decision strategies
Simultaneous = relative Sequential = absolute
What were the findings of Kneller et al (2001)?
2 x 2 independent groups design
72 college students
IV - line up (simultaneous or sequential)
- presence of target
DV - ID accuracy, decision time, confidence and self reported questionnaires
Sequential and simultaneous had equal correct IDs but sequential had fewer false IDs
Inaccuracies result of relative judgement strategies
Presentation and decision strategy not mutually exclusive
Do sequential line-ups increase accuracy?
Early research said yes but
Carlson and Carlson (2014) - sequential may be less accurate
Statistical analysis developed from chi-square and log linear to ROC analysis
What did Valentine, Darling and Memon (2007) find?
Examined strict sequential procedure instead of PACE
IV - PACE sequential vs strict sequential
- still vs moving
- present and absent
TP - 53% correct ID
More correct IDs under PACE than strict
TA - 84% rejected line-up
16% mistakenly identified innocent foil
PACE more useful ID procedure than strict
What were the findings of Wilcock and Kneller (2011)?
3x2 - PACE Seq, PACE Seq plus matrix and strict Seq
- TA, TP
Matrix no sig. affect on ID accuracy
What are the issues with line-up instructions?
Malpass and Devine (1984) - witness may believe line-up will include actual perpetrator
Cutler et al (1987) - telling a witness the culprit is in the line up = high rates of mistaken ID
Malpass and Devine (1981) Bias instructions = 78% ID innocent person
Unbiased = 33% ID innocent person
Steblay (1997) - biased instructions lead to higher rate of choosing from a TA line-up
What are the issues with line-up administration?
A police officer knows which line-up member is the culprit and can inadvertently bias the eyewitness through non-verbal behaviours (Wells, 1993)
What were the findings of Haw and Fisher (2004) ?
Showed video event then a photo line-up
Administrations led to believe it was a TP lone-up and which position they were in
High contact condition - sat at table with witness, showing line-up and recording decision
Low contact condition - handed written instructions, line-up photos and recording form and sat out of witnesses view
Results - witnesses chose innocent suspect on TA line-up above chance rate when contact is high
Reduced when sat behind witness
