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8 Eyewitness Testimony.docx

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Carleton University
PSYC 2400
Jenelle Power

Eyewitness Testimony Laboratory studies of eyewitness testimony - Independent variables- measuring, have an effect on the dependent variable • Estimator variables- things present at the time of the crime. We can’t change them. Ex: age, weapon present, etc… • System variables- affect recall. Manipulated after the crime. Ex: how we do a lineup - Dependent variables- outcome (how independent affects the dependent variable) • Recall of event • Recall of culprit • Recognition of culprit Recall of the Event/Culprit - Recall of the crime event can take two forms: • Open ended recall (free narrative) OPEN ENDED QUESTIONS: Witnesses are asked to recount what they witnessed without being prompted  Ex: tell me about the even • Direct question recall DIRECT QUESTIONS: Witnesses are asked specific questions about the event or culprit  Ex: what color was the car? What color was the suspect’s hair? - Can be written or verbal questioning • Ex: written statement with everything you can remember Interviewing Witnesses - Police officers may impede the interview (recall) process by: • Interrupting witnesses during free recall • Asking short, specific questions which may not get at critical information • Asking questions not relevant to what the witness is currently describing - Can disorient witness; decrease accuracy The Misinformation Effect - Occurs when a witness is provided with inaccurate information about an event after it is witnessed and incorporates the ‘misinformation’in their later recall • Post-event information effect - Police suggesting what they are looking for can lead to this Misinformation Studies: Results - Subtle differences in phrasing of the question may bias witness’responses • e.g., using “smashed” instead of “hit” - Changed the wording of the question - “smashed” – witness more likely to say they were going faster • Also more likely to remember broken glass in the accident even though there wasn’t any Explaining the Misinformation Effect - Three theories attempt to explain the misinformation effect: 1. Misinformation acceptance hypothesis • Witness guesses what the officer/experimenter wants the response to be and change to what they think the right answer it/ what they want to head 2. Source misattribution hypothesis • Witness has two memories (original & misinformation)  Cannot remember where each memory originated or the source of each • Develop new, separate memory • Get confused of where each memory came from • Called source amnesia 3. Memory impairment hypothesis • Original memory is replaced with the new, incorrect, information • Completely forget original memory Aiding Eyewitnesses’Recall - Hypnosis - Cognitive Interview - Enhanced Cognitive Interview Hypnosis - Hypnotically Refreshed Memory • Hypnotized in recalling an event • More details • 50/50 chance of details being true - Can increase amount of details • Details not necessarily accurate! • More suggestible • More at risk for leading questions (looking for a certain answer) - Not usually admissible in court in Canada • High risk of inaccuracy, so not reliable Cognitive Interview (more structured) - Based on four memory retrieval techniques: 1. Reinstating the context • Re-establish whole event/feelings in their mind • Put back in emotional state they were in during the event 2. Report everything • Like the free recall • No interruptions, let them get everything out, even if it seems insignificant 3. Recall event in different orders • Recall out of sequence, or in reverse order • Take pieces of event and ask things like “tell me what happened before suspect fled” or “tell me what happened right before he pulled out a gun” • Because in order people may skip some information to what they think are the critical events 4. Change perspectives • Tell story to what you think offender / victim / other witness saw happening - Increased amount of accurate information • 30% increase Enhanced Cognitive Interview - The following components were added to the original Cognitive Interview (same 4 previous steps PLUS): • Rapport building  Make person feel comfortable • Supportive interviewer behavior  Listening, looking interested, not interrupting • Transfer of control  Witness should be in control of the interview • Focused retrieval  Open-ended questions first, then followed by direct questioning • Witness compatible questioning  Ask questions that deal with what the witness is talking about  Ex: if talking about the car, ask questions about the car only Voice Identification - Accuracy increases when: • Longer voice samples • NoAccent - Accuracy decreases when: • Whispering, muffling, or emotion (screaming/crying is harder to understand) • More (large amount of) foils (voices that aren’t correct) • Target voice later in line-up • Unfamiliar accent Eyewitness Expert Testimony - There is some controversy regarding the application of research on eyewitness issues to the courts - Points of contention include: • Reliability of results across studies  Hard to say how accurate a person is • Applicability of laboratory simulations to real life situations  Brief exposure to culprit  University students  Actual eyewitnesses are difference ages, different backgrounds, but most research is only on university students (THIS CANAFFECT RECALL) Facial Composite Sketches - Graphical representation of eyewitness’memory of a face produced by a composite artist • Paper-and-pencil • Templates- clear plastic sheets with different facial features (like a nose) and you pick the ones that have the best resemblance and put them together to make a face (stack them) • Computer software - Hard to do because artist talent is hard to find, but FBI still uses this SourceAmnesia (Source misattribution hypothesis) - Memory loss that makes it impossible to recall the origin of the memory of a given event - Creating a composite may decrease likelihood of correct identification - People can change their memory through the process of recreating the sketch - Forgetting where the information came from What does the RCMPuse? - EFIT-V (electronic facial identification technique) • Based on the whole face, rather than individual features • Primarily visual, rather than verbal  Less dependent on quality of interview  Better for children, ESL, cognitive impairment - 9 faces appear with the information given, pick one, then 9 more appear, more narrowed down, keep doing this until you get the best one - Research says better at assessing an entire face,
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