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Steering in the eyewitness identification procedure

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Steering in the eyewitness identification procedure Powered By Docstoc
					Steering in the
eyewitness
identification procedure




   Wendy Alberts
   Jason Duncan
   Brian Wallace
   Prof. Steven Penrod
Content

 Example
 Eyewitness misidentification
 Present study
 Illinois study
 Major hypotheses
 Procedure and design
 Results
 Conclusion
 17 year old Ruben Cantu was convicted of murder and
  executed in 1993 . The prosecutor accused him of
  shooting his victim nine times. Now it is thought that
  he was likely innocent. The only eyewitness in this case
  was shown the picture of Ruben Cantu three times at
  which point he “recognised” Cantu. He has recanted
  and after the execution, a 15 year old accomplice
  testified that Ruben Cantu was never there….
 Source:
  http://www.ad.nl/buitenland/article65986.ece
Eyewitness Misidentifications

  In June 2008, the Cardozo Law School
   Innocence Project’s web site reports that 217
   individuals convicted of crimes have been
   exonerated with DNA testing since 1992
   (www.innocenceproject.org).

  75% eyewitness misidentifications

  Most crimes do not include DNA-rich
   biological traces.
 Wells (1978) argues that two types of variables
  can be distinguished in eyewitness research:

 (a) estimator variables and
 (b) system variables
Present Study

 The influence police officers can have on the
  eyewitness in the lineup procedure
 lineup presentation
 the presence of the perpetrator in the lineup
 giving cautionary instructions before the
  lineup procedure begins
Lineup presentation

 Simultaneous display of six photographs
 Sequential lineup in which the photo’s of the
  suspect and foils are displayed one at a time
  (Wogalter et al., 2004).

 Sequential procedure reduces the number of
  false identifications with no loss in the
  number of accurate identifications
  (Lindsay & Wells, 1985; Cutler & Penrod, 1988; Lindsay et
  al., 1991; Keller et al., 2001; Steblay & Dysart, 2008).
Illinois Study         (Mecklenburg, 2006)

 No field studies until 2006


 First field study comparing the simultaneous
  line-ups and sequential line-ups

 First field study to examine both photo arrays
  and live line-ups.
However…

 Confounds blindness and procedure in its
  design
 Lower overall rate of false identifications in
  the single-blind simultaneous condition
  than predicted by the research experiments
 police officers may not have been reporting
  foil identifications when they knew those
  identifications were erroneous or steered the
  eyewitness to the identification of the
  suspect
 UK Archival Studies –9-person arrays [row percentages]
                               Witnesses/         Suspect     Foil   No
                                Arrays              ID         ID    ID
 Slater                          843/302             36%      22%    42%
 Wright & McDaid                1561/616             39%      20%    41%
 Valentine+(VIPER)               584/295             41%      21%    39%
 Pike+                           8,800/xx            49%       -      -
 W Yorkshire-trad                1,635/xx            35%       -      -
 W Yorkshire-VIPER                940/xx             39%       -      -
 Wright & (VIPER)                134/134             58%      21%    21%
 Average [wtd]                  14494/xx             45%      21%    40%
-- suspects—mix of guilty and innocent unclear
-- 9-person arrays
-- nearly 1/3??? of IDs are clearly “bad guesses” of foils]
Witness Performance in Behrman and Davey (2001) and
Behrman & Richards (2005)-Suspect IDs in Sacramento, CA area
                             Presen-    Suspect   Foil   No
                             tations      ID       ID    ID

Showups BD                     258       76%      xxx    24%
Photoarrays BD                 284       48%      ??%    ??%
Lineups* BD                     58       50%      24%    26%
Photo (424)+                   461       52%      15%    33%
Live (37) BR
Lineup Ave [wtd]               519       51%      16%    33%

  • 6-person arrays
  • About 1 in 4 IDs is a clear error
Witness Performance from US Police Files-Stranger
Cases
                           Presen-   Suspect   Foil   No
                           tations     ID       ID    ID

California – Simul BD+BR    519       51%      16%    33%
Minnesota Photo Seq         178       35%      11%    53%
Illinois-Photo Simul         78       53%      1.3%   46%
Illinois-Photo Seq+blind     64       44%      9.4%   46%
Illinois-Live Simul          55       82%      0%     18%
Illinois-Live Seq+blind      29       46%      5.4%   49%
Queens, NY Live-Simul      2677       54%      3.0%   43%
Possible reasons for the discrepancy are buried in
the Illinois report:
◊The low number of filler IDs emerged from a
non-blind simultaneous procedure in which it
appears that the police could ignore IDs that did
not meet their "Probable cause" standards
(Appendix, pp. iii-iv)
◊This practice seems akin to the Queens practice
in which "an identification [was recorded] only if it
was based upon a high level of confidence, so that
all tentative identifications were recorded as "no
identification." (p. 43).
Influence of lineup-administrator
    Haw & Fisher ( 2004): witnesses are more
     likely to make decisions consistent with the
     lineup administrator’s expectation when the
     level of contact between the administrator
     and the witness is high rather than low

    Garrioch and Brimacombe (2001): the
     confidence of the eyewitness rises when the
     witness chooses the lineup member who their
     lineup administrator thinks is guilty.
Major Hypotheses
 1. Police-officers can influence eyewitnesses to
  select a suspect and avoid foil identifications.
 2. Police-officers can do this without the
  eyewitnesses realizing they are being led to the
  suspect or avoiding foils.
 3. Police-officers can influence eyewitnesses in a
  non-blind simultaneous procedure more than in a
  non-blind sequential procedure.
 4. Cautionary instructions have no effect on the
  identification decision of the eyewitness.
Procedure and Design (2x3x2x2)
 240 Participants (eighteen years or older)

 Two videos, one distracter video and one of a
  staged indoor theft

 Twenty minutes filler task
Identification procedure
 Cautionary instructions:
  “The suspect may not be in the lineup, you
  don’t need to make a choice and you should
  not assume that the administrator knows
  who the suspect is.”

 Lineup where the thief was present or a
  lineup with a substitute for the thief (innocent
  suspect).
 Match to description procedure.
 ‘innocent suspect’: a foil who looked very
  similar to the perpetrator.
Identification procedure (2)

 The line-up was administered either
  - simultaneous
  - sequential show-the-pictures-twice (S2)
  - sequential-with-stopping-rule (SS)

 sequential procedure: stack was back loaded to
  twelve cards (six blank cards), so the participants
  did not knew that the stack contained only six
  photographs.
     Identification procedure (3)
 An administrator who was trying to steer them to
  choose the (innocent) suspect/away from a foil or a
  blind condition
 Steering: The administrator signalled in the
  direction of the suspect with non-obvious, non-
  verbal cues and made comments like “good” and
  “that is helpful” and gave no reinforcements for the
  foils.
 Blind: screen between the administrator and the
  participant, so that the administrator couldn’t see
  the lineup and couldn’t influence the participant.
  Lineup was also randomised.
Percentages of choices participants made in the Target Absent (TA)
   condition as a function of lineup procedure

                                      Lineup Procedure
TA Lineup decision          N     SS(%)      N S2 (%)                 N    Sim(%)

False Identification        5     11.9           10    25.0           10   26.3
                                                all n.s.
Correct Rejection           33    78.6           19        47.5        8   21.1
                                 SS-S2**        SS-SM **      S2-SM*
Foil Identification         4       9.5         11     27.5           20   52.5
                                 SS-S2*         SS-SM**           S2-SM*

Total (N=120)               42 100.0            40 100.0              38    100.0

*p<.05            SS = Sequential-with stopping-rule procedure
**p<.01           S2 = Sequential-show-the-photos-again procedure
                  Sim = Simultaneous procedure
Results
  First, procedure mattered:
   - Results show superiority of the sequential
   lineup procedure when it is properly conducted
Table 2: Percentages of choices participants made in the Target
  Present (TP) condition as a function of lineup procedure

                                      Lineup Procedure
TP Lineup decision    N SS(%)                   N S2 (%)             N Sim(%)


Hit                   8       20.5              18    42.9           19      48.7
                              SS-S2**           SS-SM*         S2-SM

Lineup Rejection      23       59.00            11    26.2           7    17.9
                               SS-S2**          SS-SM**        S2-SM

Foil Identification   8        20.5             13   31.0            13   33.3
                                     all n.s.
Total (N=120)         39 100.0                  42 100.0             39      100.0
*p<.05                     SS = Sequential-with stopping-rule procedure
**p<.01                    S2 = Sequential-show-the-photos-again procedure
                           Sim = Simultaneous procedure
Results
  The first hypothesis, that police officers can
   influence eyewitnesses to select a suspect and
   avoid foil identifications was confirmed.

  steering administrator: more suspect
   identifications.

  They could be steered in every procedure
Percentages of choices in the Target Absent (TA) and the Target
Present (TP) condition, as a function of administrator steering
                                     Administrator
                             Steering                 Blind
  Lineup and decision       N      (%)            N           (%)
Target Absent lineup
  False Identification      19      31.7          6            10.0**
  Correct Rejection         28      46.7          32           53.3
  Foil Identification       13      21.7          22           36.7
  Total (N=120)             60     100.0          60          100.0


Target Present Lineup
  Hit                       34      56.7          11           18.3**
  Rejection Lineup          16      26.7          25           41.7
  Foil Identification       10      16.7          24           40.0**
  Total (N=120)             60     100.0          60          100.0
Results
  The second hypothesis, that police officers can
   influence eyewitnesses to select a suspect and avoid
   foil identifications without the eyewitnesses
   realizing they were being led was not entirely
   confirmed.
  Witnesses in the steering condition mentioned
   things the administrator did or said that influenced
   their decision more than witnesses in the blind
   condition (χ2=30.84, p<.01).
  Witnesses also indicated that the administrator
   influenced their decision significantly more when the
   administrator was steering than when he was blind
   [t(233)=2.171, p<.01].
Results

 Influence of the administrator on their decision:
  - steering (M=2.73) vs. blind (M=2.10).
 low end of a 9-point scale


 Witnesses thought lineup photos and their memory
  were much more influential than the administrator:
  -photos steering (M=4.98) vs photos blind (M=5.77) (sg)
  -memory steering (M=7.32) vs memory blind (M=7.25)
Results
  The third hypotheses, that police officers can
   influence eyewitnesses to select a suspect in a
   non-blind simultaneous procedure more than in
   a non-blind correct conducted sequential
   procedure (SS) was confirmed.

  Simultaneous procedure (55.3%) vs SStop
   procedure (26.8%) .
Results
 No significant difference was found between
  witnesses with a S2 procedure (51.2%) and the
  simultaneous procedure (55.3%) when they were
  in the steering condition.

 That is, when the sequential procedure was not
  conducted properly (showing them the pictures
  twice), it was as easy to steer the witness to the
  (innocent) suspect as in the simultaneous
  procedure.
Results

 The fourth hypothesis, that the cautionary
  instructions have no effect on the identification
  decision of the eyewitness was also confirmed.
Conclusion

 If we compare the results of the present study
  with those of Illinois and Queens, we see that the
  steering administrator is a plausible explanation
  for the substantially lower overall rate of false
  identifications in the non-blind simultaneous
  conditions used in those studies.
 In the present study the witnesses made fewer
  foil identifications in the steering condition than
  the blind condition and did so without
  dramatically triggering witness suspicions.
Questions?

 alberts_wendy@hotmail.com


 0(031)6-45092028

				
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posted:5/4/2011
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