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Eyewitness
Testimony



             1
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
The Stages of Memory

            Encoding




             Storage



             Retrieval

                         3
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
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
Elizabeth Loftus on the Fallibility
of Memory


http://www.youtube.com/watch?v=hER-
  5mdIoN0




                                      6
Examining Eyewitness Issues
   Eyewitness issues can be studied using a
    variety of methods:
      Laboratory simulations

      Archival data

      Naturalistic environments




                                               7
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)

http://www.youtube.com/watch?v=_RLvSG
  YxDIs&feature=fvw

                                                 8
Examples of Misinformation
Manipulations
 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
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
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
Explaining the Misinformation
Effect
   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
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
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
Naturalistic Research – Yuille
Study Con’t
                Accuracy of Eyewitnesses (Mean %)
                        Police Interview        Psychologist Interview

Type of Detail
Action Detail                              82                      82

Person Descriptions                        76                      73

Object Descriptions                        89                      85

Total                                      82                      81



                                                                         15
Naturalistic Research – Yuille
Study Con’t (bank robberies)
                Accuracy of Eyewitnesses (Mean %)
                        Police Interview        Psychologist Interview

Type of Detail
Action Detail                              99                      83

Person Descriptions                        84                      80

Object Descriptions                        90                      82




                                                                         16
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
Facilitating Eyewitness Recall
   Methods used in the investigative process to
    aid eyewitness recall include:
      Hypnosis

      Cognitive Interview

      Enhanced Cognitive Interview




                                                   18
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
Cognitive Interview Components
(Geiselman et al., 1986)
Cognitive         Reinstate the context
reinstatement     surrounding the incident.
Report everything Report all details including those
                  believed to be insignificant.

Recall event in    Go through the incident in
different orders   different sequences.
Change             Take the perspective of someone
perspectives       else witnessing the event.

                                                       20
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
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
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
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
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
Accurate Identification Decisions
   Comparisons Between Lineup Types:

Type of   Guilty            Correct Decision
Lineup    Culprit
          Present
Target-     Yes          Correctly identify culprit
Present
Target-     No      Correctly reject all lineup members
Absent
                                                      26
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
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
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
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
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
32
33
34
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
Perpetrator described as a white male
approximately 6’2” tall, dark hair at ear length and
no facial hair. What’s wrong with this lineup?




                                                       36
Talk about sticking out like a
sore thumb!




            www.psychologytoday.com/files/u107/lineup.jpg

                                                            37
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
Effects of Alcohol on
Recognition (Yuille et al.)

            Target Present        Target Absent

Condition
            Correct   Incorrect   Correct   Incorrect


Alcohol     90%       9%          62%       37%

Control     86%       13%         76%       23%




                                                        39
Effects of Marijuana on Recall
(Yuille et al.)
   Immediate Accuracy
     Marijuana condition: 83 %
     Control condition: 85-87%

   Delayed
     Slight increasein recall
     Motivation factors




                                  40
Effects of Marijuana on
Recognition
 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

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Forensic Psychology:Eye Witness Testimony

  • 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. The Stages of Memory Encoding Storage Retrieval 3
  • 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. 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. Elizabeth Loftus on the Fallibility of Memory http://www.youtube.com/watch?v=hER- 5mdIoN0 6
  • 7. Examining Eyewitness Issues  Eyewitness issues can be studied using a variety of methods:  Laboratory simulations  Archival data  Naturalistic environments 7
  • 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) http://www.youtube.com/watch?v=_RLvSG YxDIs&feature=fvw 8
  • 9. Examples of Misinformation Manipulations  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. 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. 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. Explaining the Misinformation Effect  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. 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. 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. Naturalistic Research – Yuille Study Con’t Accuracy of Eyewitnesses (Mean %) Police Interview Psychologist Interview Type of Detail Action Detail 82 82 Person Descriptions 76 73 Object Descriptions 89 85 Total 82 81 15
  • 16. Naturalistic Research – Yuille Study Con’t (bank robberies) Accuracy of Eyewitnesses (Mean %) Police Interview Psychologist Interview Type of Detail Action Detail 99 83 Person Descriptions 84 80 Object Descriptions 90 82 16
  • 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. Facilitating Eyewitness Recall  Methods used in the investigative process to aid eyewitness recall include:  Hypnosis  Cognitive Interview  Enhanced Cognitive Interview 18
  • 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. Cognitive Interview Components (Geiselman et al., 1986) Cognitive Reinstate the context reinstatement surrounding the incident. Report everything Report all details including those believed to be insignificant. Recall event in Go through the incident in different orders different sequences. Change Take the perspective of someone perspectives else witnessing the event. 20
  • 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. 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. 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. 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. 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. Accurate Identification Decisions  Comparisons Between Lineup Types: Type of Guilty Correct Decision Lineup Culprit Present Target- Yes Correctly identify culprit Present Target- No Correctly reject all lineup members Absent 26
  • 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. 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. 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. 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. 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. 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. Perpetrator described as a white male approximately 6’2” tall, dark hair at ear length and no facial hair. What’s wrong with this lineup? 36
  • 37. Talk about sticking out like a sore thumb! www.psychologytoday.com/files/u107/lineup.jpg 37
  • 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. Effects of Alcohol on Recognition (Yuille et al.) Target Present Target Absent Condition Correct Incorrect Correct Incorrect Alcohol 90% 9% 62% 37% Control 86% 13% 76% 23% 39
  • 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. Effects of Marijuana on Recognition  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