EYEWITNESS TESTIMONY

EYEWITNESS TESTIMONY

1. ANXIETY

   • STUDY 1: JOHNSON + SCOTT (1976)
     • PROCEDURE
       • Ppts sat in a waiting room believing they were going to take part in a lab study
       • Each ppt heard an argument in the next room:
         • LOW ANXIETY CONDITION: a man walked through the waiting room w/ a pen + greasy hands
         • HIGH ANXIETY CONDITION: argument was accompanied with the sound of breaking glass, than a man walked through the room holding a knife covered in blood
       • Ppts were later asked to pick out the man from a set of 50 photos
     • FINDINGS + CONCLUSIONS
       • 49% in LOW ANXIETY condition were able to identify the man
       • 33% in HIGH ANXIETY condition were able to identify the man
       • The tunnel theory of memory argues that people suffer WEAPON FOCUS as it is a source of danger and anxiety
   • STUDY 2: YUILLE + CUTSHALL (1986)
     • PROCEDURE
       • Real life crime -> gun shop owner shot a thief dead: 21 witnesses, 13 agreed to participate in the study
       • Ppts were interviewed 4-5 months after the incident
       • Accounts were compared to the police interviews at the time of the shooting
       • Witnesses rated how stressed they felt at the time of the incident
     • FINDINGS + CONCLUSIONS
       • Very accurate recounts with little change after 5 months
       • Some details were less accurate (e.g. colours of items, ages, weights, heights
       • Ppts who reported the highest levels of stress were most accurate (88% compared to 75% for the less-stressed group)
   • INVERTED U-THEORY
     • YERKES + DODSON (1908) argue that the relationship between performance and stress is curvilinear rather than linear
   • AFFECTS MEMORY
     • DEFFENBACHER (1983) found that lower levels of anxiety did produce lower levels of recall accuracy
     • Recall accuracy increases with anxiety up to an optimal point, which then decreases after stress increases past the point

2. MISLEADING INFORMATION

   • LEADING QUESTIONS
     • RESPONSE-BIAS
       • Wording of a question has no enduring effect on memory but influences the kind of answer given
     • SUBSTITUTION
       • Wording of a question does affect memory, it interferes with the original memory, distorting the accuracy
   • STUDY 1: LOFTUS + PALMER (1974)
     • PROCEDURE
       • 45 ppts watched film clips of car accidents + then answered questions about speed
       • CRITICAL QUESTION: 'About how fast were the cars going when they hit each other
       • Five groups of ppts, each group given a different verb: HIT, CONTACTED, BUMPED, COLLIDED or SMASHED
     • FINDINGS + CONCLUSIONS
       • CONTACTED: mean estimate speed = 31.8 mph
         • SMASHED: mean estimate speed = 40.5 mph
       • The verb biased eyewitness recall of an event --> smashed implied a faster speed than contacted
   • POST-EVENT DISCUSSION (PED)
     • MEMORY CONTAMINATION
       • When co-witnesses discuss a crime, they mix information from other witnesses into their own memories
     • MEMORY CONFORMITY
       • Go along with others to win social approval because they believe other witnesses are right
   • STUDY 2: GABBERT ET AL (2003)
     • PROCEDURE
       • Paired ppts watched a video of the same crime, but FILMED so each ppt could see elements in the event that the other could not
       • Both ppts discussed what they had seen on the video before individually completing a test of recall
     • FINDINGS + CONCLUSIONS
       • 71% of ppts mistakenly recalled aspects of the event that they did not see in the video but had picked up in the PED
       • CONTROL GROUP (no discussion) --> no errors

3. COGNITIVE INTERVIEW (CI)

   • BASED ON PSYCHOLOGICAL UNDERSTANDING OF MEMORY
     • FISHER + GEISELMAN (1992) claim that EWT could be improved if the police use techniques based on psychological insights into how memory works
   • REPORT EVERYTHING
     • Witnesses are encouraged to include every detail of an event (even if irrelevant)
     • Seemingly trivial details could be important and may trigger other memories
   • REINSTATE THE CONTEXT
     • Witness returns to original crime scene 'in their mind' and imagines the environment (e.g. weather) and their emotions (e.g. anger)
       • Based on context-dependent forgetting as cues from the context may trigger recall
   • REVERSE THE ORDER
     • Events are recalled in a different chronological order
     • Prevents people using their expectations of how the event must've happened rather than the actual events
     • Prevents dishonesty
   • CHANGE THE PERSPECTIVE
     • Witnesses recall from other people's perspectives
     • Prevents the influence of expectations + schemas on recall
   • ENHANCED COGNITIVE INTERVIEW
     • FISHER ET AL (1987) developed additional elements of the CI
     • Included a focus on the social dynamics of interaction
     • Also includes ideas such as reducing anxiety, minimising distractions ect.