Forensic Psychology:Eye Witness Testimony


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This lecture slide concerns the accuracy report of eye witness testimony. How accurate are eye-witness testimonials? And how can we interview witness so that their reports can be more accurate? It identifies the 'Cognitive Interview Model' which is a interview approach for increasing accuracy of reports while minimizes false information. One of the main mistake of interviewers are asking misleading questions. For instance, 'did you see the gun?' as opposed to 'did you see 'a' gun?' First part was misleading because it implies that a gun was witnessed when in fact there may not have been a gun present.

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Forensic Psychology:Eye Witness Testimony

  1. 1. EyewitnessTestimony 1
  2. 2. The Role of Memory Eyewitness testimony relies on storing and recalling information Storing memories requires several steps including attention, encoding, short term memory, and long term memory Not all memories pass successfully through these stages and problems may occur at each stage 2
  3. 3. The Stages of Memory Encoding Storage Retrieval 3
  4. 4. Types of Eyewitness Memory There are two types of memory retrieval that eyewitnesses perform: 1. Recall Memory Reporting details of previously witnessed event/person 2. Recognition Memory: Reporting whether what is currently being viewed/heard is the same as the previously witnessed person/event of interest 4
  5. 5. James Buckhout Wanted to promote legal change - wrong people were being sent to jail 1974 demonstration of the fallibility of memory involving a staged robbery aired on a local TV station  Generalizability issues? 5
  6. 6. Elizabeth Loftus on the Fallibilityof Memory 5mdIoN0 6
  7. 7. Examining Eyewitness Issues Eyewitness issues can be studied using a variety of methods:  Laboratory simulations  Archival data  Naturalistic environments 7
  8. 8. 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 (Loftus, 1975) YxDIs&feature=fvw 8
  9. 9. Examples of MisinformationManipulations Explicit  Did the person carrying the hammer walk or run out of the store? (when a screwdriver was present instead of a hammer) Implicit  Did you see the hammer? (when no hammer was present) 9
  10. 10. Designing a Misinformation Study Two groups of participants watch a videotape of a staged crime Erroneous information about the crime is presented to one group of participants Participants are asked a set of neutral questions and must respond based on what they saw on video 10
  11. 11. Misinformation Studies: Results Participants who are given misinformation provide different reports than those who receive no misleading information Subtle differences in phrasing of the question (e.g., using „smashed‟ instead of „hit‟), may bias witness responses (Loftus & Palmer, 1974) 11
  12. 12. Explaining the MisinformationEffect Although there is debate as to why the misinformation effect occurs, what we do know is that it does occur Misinformation effect cold be used to explain some “recovered” memories of childhood sexual abuse Raises serious questions about reliability of eyewitness testimony 12
  13. 13. Archival Research Witnesses/victims of events where it is clear that a crime is being committed remember far more detail and are more accurate Eyewitnesses are more accurate than results of laboratory studies suggest Criticism: Maybe these cases are closed because these witnesses are better in their recollection 13
  14. 14. Naturalistic Research Must have enough physical evidence & as many witnesses as possible John Yuille (1982) – Gun store robbery  20 witnesses  Police interview of witnesses at scene  Psychologist interview 5-6 months later  Able to study factors of time and reliability  Tried Loftus‟ misinformation effect 14
  15. 15. Naturalistic Research – YuilleStudy Con’t Accuracy of Eyewitnesses (Mean %) Police Interview Psychologist InterviewType of DetailAction Detail 82 82Person Descriptions 76 73Object Descriptions 89 85Total 82 81 15
  16. 16. Naturalistic Research – YuilleStudy Con’t (bank robberies) Accuracy of Eyewitnesses (Mean %) Police Interview Psychologist InterviewType of DetailAction Detail 99 83Person Descriptions 84 80Object Descriptions 90 82 16
  17. 17. Conclusions from Yuille Studies Could not affect with deception High recall & accuracy even with delays Possible confounds:  Mediacoverage  Maybe something about the nature of crime  Remarkable memory  Repeating story so many times Extremely valuable research! 17
  18. 18. Facilitating Eyewitness Recall Methods used in the investigative process to aid eyewitness recall include:  Hypnosis  Cognitive Interview  Enhanced Cognitive Interview 18
  19. 19. Hypnosis Can be used to facilitate retrieval of memories. However, memories may or may not be accurate About 10% of the population cannot be hypnotized and 5-10% are highly suggestible (Hilgard, 1965) Information obtained under hypnosis is not usually admissible in court 19
  20. 20. Cognitive Interview Components(Geiselman et al., 1986)Cognitive Reinstate the contextreinstatement surrounding the incident.Report everything Report all details including those believed to be insignificant.Recall event in Go through the incident indifferent orders different sequences.Change Take the perspective of someoneperspectives else witnessing the event. 20
  21. 21. Enhanced Cognitive Interview The following components were added to the original Cognitive Interview (Fisher & Geiselman, 1992):  Rapport building  Supportive interviewer behaviour  Transfer of control  Focused retrieval  Witness compatible questioning 21
  22. 22. Cognitive Interview: Results Both types of cognitive interviews elicit more information than “standard police interviews”, without an increase in inaccurate information It still remains unclear as to which components of the cognitive interview elicit this increase in accurate information (Kebbell & Wagstaff, 1998) 22
  23. 23. Lineup Procedures Witnesses are frequently asked to identify a culprit from a lineup Lineups contain the suspect who is placed among a set of individuals who are known to be innocent for the crime in question, called foils or distractors 23
  24. 24. R v. Virag Man went on rampage in England and attacked citizens and police officers Suspect was put in a line-up  8/17 picked suspect  5/17 picked a foil  4/17 made no identification Found guilty and sentenced to 10 years- pardoned after 5 Led to the Royal Commission of Inquiry 24
  25. 25. Types of Lineups To accurately assess the rate at which real witnesses will correctly identify culprits two types of lineups are needed in research:  Target-present lineups  Lineup contains the culprit  Target-absent lineups  Lineup contains an innocent suspect 25
  26. 26. Accurate Identification Decisions Comparisons Between Lineup Types:Type of Guilty Correct DecisionLineup Culprit PresentTarget- Yes Correctly identify culpritPresentTarget- No Correctly reject all lineup membersAbsent 26
  27. 27. Types of Lineup Judgments Two types of judgments may be used in lineup procedures:  Relative judgment Comparing lineup members to one another and choosing the one who looks most like culprit  Absolute judgment Each member of the lineup is compared to the witness‟ memory 27
  28. 28. Lineup Procedures Walk-By Conducted in natural environment, the witness is escorted to an area the suspect is likely to be. May be useful if no photo of the suspect is available Showup Only the suspect is shown to the witness. Has been criticized as biased because the witness knows the person the police suspect 28
  29. 29. Lineup Procedures (continued) Simultaneous lineup  Present all lineup members at the same time to the witness. Encourages witnesses to make a relative judgement Sequential lineup  Members are presented one at a time, must decide if it is or is not the criminal before seeing another photo/person. Encourages witnesses to make absolute judgements 29
  30. 30. Lineup Procedure Effectiveness Sequential lineups reduce the likelihood that an incorrect identification will be made with a target-absent lineup (Lindsay & Wells, 1985) However, recent research suggests that the superiority of sequential over simultaneous lineups may be the product of methodological factors (McQuinston-Surrett et al., 2006, 2009) 30
  31. 31. Fair Lineups It is important that a lineup remain fair, that characteristics of the suspect do not stand out from those of foils:  Gender and race should always be matched across lineup members  Features that the witness mentioned in the culprit‟s description should be matched across lineup members (unless doing so would cause the suspect to stand out) 31
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  35. 35. Biased Lineups Biased lineups imply who the police suspect, thereby suggesting who the witness should identify There are many types of biases that increase false identification:  Foil bias  Instruction bias  Clothing bias 35
  36. 36. Perpetrator described as a white maleapproximately 6’2” tall, dark hair at ear length andno facial hair. What’s wrong with this lineup? 36
  37. 37. Talk about sticking out like asore thumb! 37
  38. 38. Effects of Alcohol on Recall(Yuille et al.) Immediate Accuracy  Alcohol condition: 85 – 99%  Control condition: 88 – 99% Delayed Accuracy  Alcohol condition: 83 – 99%  Control condition: 87 – 98% 38
  39. 39. Effects of Alcohol onRecognition (Yuille et al.) Target Present Target AbsentCondition Correct Incorrect Correct IncorrectAlcohol 90% 9% 62% 37%Control 86% 13% 76% 23% 39
  40. 40. Effects of Marijuana on Recall(Yuille et al.) Immediate Accuracy  Marijuana condition: 83 %  Control condition: 85-87% Delayed  Slight increasein recall  Motivation factors 40
  41. 41. Effects of Marijuana onRecognition Just like in the alcohol study, mistakes were most likely to occur in the target absent line-up 3 X more likely to make a false identification in the target absent condition than in the placebo condition 41