Eyewitness Identification
I. Perception
A. Basic Psychophysiology
1. General idea: There are limitations on the sensitivity and precision of human
sensory organs.
2. Vision
a) Example: Buckhout (1974) reports a case in which a police officer
testifies that he saw the face of a black man in a darkened doorway near a
street light from inside a vehicle parked 120' away from the doorway.
b) Lighting:
i) Observations made while eyes are adjusting to large changes in
brightness (e.g. going from dark room into daylight, looking at
brightly lit scene and then into the surrounding darkness) is very
poor. Dark adaptation takes 20-25 minutes to complete.
ii) Vision at twilight is particularly poor because neither the rods
nor the cones are at their peak functioning.
iii) No color vision at night.
c) Distance: Accuracy of perception is proportional to the visual angle
subtended by an object. This implies that objects that are far away or at
odd angles relative to the perceiver will not be accurately perceived.
i) Example: Allegheny Airlines v. US et al. Fifty high school
students playing football witness midair collision. Report seeing planes
collide while airliner fails to take evasive action. Testify to seeing
numbers and letters on the planes and falling luggage and bodies.
However, at the time of the collision, the planes were flying in clouds, the
sound of the impact would have taken about 6 seconds to reach the
ground, and the angle subtended by the numbers and luggage would have
been so small that the normal human observer would have been unable to
perceive them.
d) Time: The longer the time of exposure, the more opportunity for
information processing. However, how does one determine the length of
time exposed? Memory for time elapsed depends on the "number" of
events that occur and the condition of the individual. Under stress,
individuals appear to overestimate time elapsed. Also, individuals may
not use the time available to encode relevant information.
e) Speed: (Distance/Time) Individuals are very poor at judging speed.
One can learn to judge speed relative to surrounding objects, but there are
limitations (e.g. trained pilots mistake expanding cloud of gas several
miles away for object speeding towards them).
3. Hearing: Accuracy depends on amplitude of signal and amplitude of
background noise.
a) Example: There are cases in which witnesses report "hearing"
conversations over traffic noise several floors below.
4. Individual Differences: Individuals who are old, ill, fatigued or drugged often
cannot hear or see as well as others.
a) Example: People v Davis (1972). Eyewitness testifies to seeing colors
notably red tinges in the hair of Ms. Davis in a van later used in an escape attempt
at the Marin County courthouse. Eyewitness admits to being color blind. Expert
for the defense assumes that witness was red/green color blind (occurs in about 510% of the male population). Rebuttal expert testifies that the first expert was
incorrect and that the witness was monocromatic (an extremely rare form of total
color blindness).
B. Attention
1. Problem of not looking where the action is. Why should you? Even if one is
looking in the right direction, one may not attend to the legally relevant factors.
Why should you? The important thing for the witnesses is usually determining
where the danger is and how to avoid it -- not what color eyes the suspect had or
what the license plate number was.
2. Stress & Weapons Focus
Effects of stress: Under high stress individuals tend to be less accurate and tend
to focus attention on source of stress.
i) Johnson & Scott (1976) Subjects waiting for an experiment either 1)
hear innocuous conversation about equipment failure and then see subject
enter room with grease pencil, utter single line and then leave or 2) hear
arguing along with crashing objects and then see subject enter room with
bloodied letter opener, utter a single line and then leave. Subjects then
asked to identify target person from set of 50 photographs. Results:
% Correct ID
Weapon Present
33
Weapon Absent
44
Note: r(confidence, accuracy)=-.21
ii) Loftus (1987)
S view slide show of robbery with either a weapon present or not.
Percent correct ID
Weapon present
11
Weapon absent
39
iii) Clifford & Holin (1981)
S view videotape of controntation which is either violent or non-violent
and with either 1 or multiple perpetrators. In the single perpetrator
condition:
Percent correct ID
Violent
30
Nonviolent
40
iv) Keuhn (1974)
Survey of completeness of police reports. When victim injured, 40% of
the reports are complete. When victim uninjured, 61% are complete.
Implication: Stress of crime may lower accuracy of witness. Weapon may
be a source of stress and focus witnesses attention on it.
3. Seriousness
Leippe, Wells, & Ostrom (1978)
S witness theft of object of either high (calculator) or low (cigarettes) value and
find out value of object either before or after theft.
Percentage of Correct Identifications
Seriousness (Value)
Time of Knowledge
High
Low
Before
56.3a
18.8b
b
After
12.5
35.3b
Implication: When crime is serious, witnesses pay more attention to theft and are
better able to recognize perpetrator. Not memory effect because if find out
seriousness after event there is no effect.
II. Encoding
A. Cultural Biases
1. Cross-Racial Identification: Differentiation increases with experience:
a. Cross, Cross, & Daly (1971)
300 subjects black and white, male and female, from 4 different age
groups tested for recognition of 12 photographed faces embedded in 24
new faces.
% Correct Identification
Black faces
White faces
Black subjects
39
40
White subjects
27
45
Integration not entirely effective in eliminating difference
Integrated Setting
Black faces White faces
Black subjects
38
38
White subjects
22
34
b. Malpass & Kravitz (1969)
B. Personal biases
1. Group Membership
Hastorf & Cantril
C. Temporary biases
Segregated Setting
Black faces White faces
40
41
25
48
III. Storage
A. Stages of memory
1. Sensory Information Store
2. Short term memory
3. Long term memory
i) Ebbinghaus curve
ii) HAM model
B. Episodic Memory
1. Retroactive Amnesia following trauma
IV. Retrieval
A. Form of questions
Loftus & Zanni (1975)
Item
Experiment I
Response
Y
N
IDK
Experiment II
Response
Y
N
IDK
B. Type of questions
Present
Article Used
“the” “a”
Not Present
Article Used
“the” “a”
17
60
23
20
29
51
15
72
13
7
55
38
18
62
20
15
28
57
20
69
11
6
56
38
Lipton (1977)
Subjects watch videotape of peaceful scene in park which is interupted by man
being robbed and shot. S's asked about details in film.
Accuracy
Quantity
Type of Questioning
Narrative
Interrogatory
91%
56%
21%
75%
Implication: Narrative questions provide less information than interrogatory
questions, but more of the information is accurate
C. Faces
1. Line-ups
Malpass & Devine (1981)
S witness vandalism in classroom. Asked to ID offender given biased (imply
offender is present) or unbiased instructions.
Instructions
Choice
Biased
Unbiased
Vandal Present
Vandal
Other
No choice
75
25
0
83
0
17
Other
No choice
78
22
33
67
Vandal Absent
Implication: When S's believe that suspect is present will make more errors than
when instructions are unbiased. When suspect is not present and the instructions
are biased, S's will nevertheless tend to pick someone.
Gorenstein & Ellsworth (1980)
S's watch target person interupt class. Half of the class is dismissed. Other half of
the class asked to view photo line-up and pick out target person if possible (target
not present). Four to six days later all S's asked to examine a second photo lineup containing the target.
Proportion of S's in group making choices
Group
Prior Choice
No Prior
Choice
Choice
Target
.22
.39
Previous Choice
.44
-Implication: When S's view previous photo line-up and select photo, they are
likely to choose same photograph in subsequent line-ups even if they are wrong
initially and actual target person appears in the second line-up.
Brown, Deffenbacher, & Sturgill (1977)
D. Judging accuracy of witnesses
Lindsay, Wells, & Rumpel (1981)
S observe theft of calculator under conditions designed to produce Low, Medium, &
Highly accurate recognition.
Percent Accurate Identification
Low
33
Situation
Medium High
50
74
Implication: Manipulations worked.
Self Reported Confidence (7 pt scale)
Accurate Witnesses
Inaccurate witnesses
Situation
Low Medium High
4.3
4.3 5.0
3.4
3.8 3.9
Implication: No effect of situation, slight effect of accuracy
Percentage of Mock-jurors believing witness
Witness Confidence
Low
High
Low
47
76
Situation
Medium
54
76
High
76
78
Implication: Jurors unable to take into account situational influences in determining
whether witness is accurate. When the witness is confident, jurors tend to believe the
witness.
Wells (1979)
Wells, Ferguson, & Lindsey (1981)
V. Improving Eyewitness Performance
A. Training
1. Tickner & Poulton (1975)
2. Woodhead et al (?)
B. Hypnosis
1. Kihlstrom (1987)
C. Cognitive Interview
1. Geiselman
D. Other Techniques
VI. Law
A. U.S. v Wade (1967)
Attorney must be present at lineup
B. Gilbert v CA (1967)
Wade protection extended to states; tainted line-up cannot be introduced at trial.
C. Stovall v Denno (1967)
Show-up is inherently suggestive; however, use depends on “totality of
circumstances.”
D. Kirby v Illinois (1972)
Right to counsel at lineup only after adversary process is begun.
E. Neil v Biggers (1972)
Totality of circumstances elaborated.
F. Manson v Brathwaite (1977)
Training of witnesses recognized!
VII. Repressed Memories & False Memories
A. Psychology
B. Law