Eye Witness Testimony

Eye Witness Testimony

1. Factors influencing accuracy

   • Anxiety
     • Definition: unpleasant emotional state where we fear that something bad is about to happen
     • Yerkes Dodson Law: People with mid anxiety are more accurate eye witnesses
     • Deffenbacher 2004: Meta Analysis of 18 studies, looking at effects of heightened anxiety on accuracy of eyewitness recall
       • Showed high levels of stress had negative impact on accuracy of eye witness memory for adults but not for kids
         • High reliability
         • - May be outdated - May used different methodology
     • Christiansen & Hubinette 1993: Questionned 58 real witnesses who saw bank robberies
       • The witnesses had been threatened in some way were more accurate in recall and remembered more details, than those who had been onlookers and less emotionally aroused.
         • Continued to be true 15 months later
           • Emotional arousal may actually enhance the accuracy of memory.
     • Loftus 1987: Weapons Effect: Arousal can focus witness on central details of attack(weapon) than morethe peripheral details(what was going on)
       • Johnson & Scott 1976: Tested the effect by having 2 conditions; one with a weapon and other without.
         • Participant heard discussion in next room. Condition 1: Man came out holding pen and grease on hands. Condition 2: Discussion more heated, and man had paperknife covered in blood.
           • Asked to identity men from 50 pictures, participants in condition 1: 49% accurate and condition 2: 33% accurate
             • Suggests that weapon could of distracted attention from the man and could explain why eyewitnesses sometimes has poor recall for certain details of violent crimes.
   • Age
     • Parker & Carranza 1989: Children as witnesses: Primary vs college students in ability to identity target individual correctly
       • Show slide sequence of mock crime. and asked to identify the target
         • Child witnesses had higher rate off choosing than adult witnesses, but more likely to make errors of identification than college students
       • Don't have schema's
       • Like to please, so may just pick someone just so they can be helpful
     • Yarmey 1993: Age differences in accuracy: Stopped 651 adults in public places and asked to recall a women who they spoke to
       • Asked adults to recall physical characteristics of young women who they had spoken to for 15sec just 2mins earlier.
         • Young (18-219 & middle-aged (30-44) were more confident in recall than older (45-65). Significant differences in accuracy of recall-oldest inferior to other 2 groups in terms of accuracy of recall
     • Anastasi & Rhodes 2006: Own-age bias: Showing photographs to 3 age groups to see recognition rates
       • Three groups: 18-25; 35-45; 55-78. Shown 24 photographs: rate attractiveness, then shown 48 photographs 24 from before and 24 new photographs added as 'distractors' .
         • Corrected recognition rates, showed that young and middle-aged participants were significantly more accurate than older participants. All age groups were more accurate in identifying photographs from their own age group
         • Brigham & Malpass 1985: Explaining own-age bias: More contact with those from certain age/ethnic group, better our memory would be for such individuals &less experience with certain group, more own-age bias
   • Leading Questions
     • Loftus & Palmer 1974: 45 students saw a film of a car crash
       • Dependent.V: Estimate car speed Independent.V: When it crashed/bumped/hit/smashed
         • - Has low ecological validity - No shock value - In UK tested on non drivers
         • High internal validity
       • Questionnaire: asked to describe accident and related questions. "How fast were the cars going when they hit?" One group asked this question, 5 other groups given verbs: smashed, collided, bumped or contacted instead of hit
         • Speed estimates: 'smashed'-40.8mph, 'contacted'-30mph
       • Supporting evidence for Loftus & Palmer 1974
         • Loftus: Stop Yield Sign: 2 Groups shown STOP or YIELD
           • Half group: Car stopping at junction with STOP, other group car stops at YIELD. Question- "Did another care pass the red car when it was at the YIELD/STOP sign?" Then shown pair of slide and identify which slide was original
             • 75% Participants who had consistent Q's picked right slide. 41% who had misleading Q's picked right slide
               • Misleading Q affected recall, as Loftus & Palmer 1974 concluded originally
     • Loftus 1979:participants saw red purse being stolen
       • Can fool participants with leading Q's about minor details but not with colour of purse.
         • Highly relevant material isn't changeable by leading Q's
     • Yuille & Cutshall: Participants saw armed robbery in Canada
       • 13 people were interviewed 4 months after witnessing robbery and included 2 misleading Q's.
         • Witnesses gave accurate recall that matched their initial detailed reports.
           • 'Car Crash' tricked successfully, however Yuille wasn't able to mislead them. Suggests post-event information may not affect memory in real-life EWT
   • Individual Differences: Alcohol can affect accuracy: Clifasefi et al 2006: Mildly intoxicated compared to completely sober. 82% of intoxicated (compared to 46% sober) were not aware someone dressed in gorilla suit had walked across screen while they were watching video of students throwing basketball to each other.

2. Cognitive Interview; Four Components

   • 1. Report Everything: Encouraging to report every detail of even
   • 2. Mental Reinstatement: Recreate original context
   • 4. Changing the Perspective: Recall event from different perspectives
   • 3. Changing the Order: Recall event from different order

3. Memory Improvement Strategies

   • Verbal Mnemonics:
     • Acronym: word/sentence formed from initial letters of other words. e.g. ROY G. BIV for the rainbow colours
     • Acrostic: poem/sentence where 1st letter in each line or word forms item to be remembered M.y V.ery E.asy M.ethod J.ust S.peeds U.p N.aming P.lants- for order of plants
     • Rhymes: groups of words with an identity and rhythm
     • Chunking: dividing a long string of information into memorable chunks
     • taken place in artificial, lab conditions, with material appropriate for mnemonic strategies.
     • Gruneberg 1973: survey of psychology students revising for final exams. 30% student used mnemonics. Glidden 1983: verbal mnemonics effective in children with learning difficulties.
   • Visual Imagery Mnemonics: method of loci. associate thing with different places/rooms in the order that they are to be recalled.
   • O'Hara 2007: training in use of mnemonic techniques has long-term benefirs for older adults. Atkinson 1975: Participants trained in use of keywords learned a lot more Russian vocab than control group with no training

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