eyewitness memory
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MODES OF PRESENTATION, POST-EVENT INFORMATION, EVENT EMOTIONALITY AND GENDER AFFECTING THE EYEWITNESS ACCURACYTRANSCRIPT
MODES OF PRESENTATION, POST-EVENT INFORMATION, EVENT EMOTIONALITY AND GENDER
AFFECTING THE EYEWITNESS ACCURACY
Ari Sudan Tiwariand
Chandra Bhal Dwivedi
Department of PsychologyBanaras Hindu University
Varanasi-221005
EYEWITNESS MEMORY
Nature of Eyewitness Memory
• Murder, shootout, brutal assault, robbery, accidents, etc.
• Emotional, stressful and arousal inducing
• Reconstructive process
• High suggestibility
• Fragile in nature- very high level of inaccuracy
FACTORS AFFECTING EYEWITNESS MEMORY ACCURACY
• Post-event information- Misinformation effect
• Stress and arousal- Cue-utilizing hypothesis and weapon focusing
• Personality type- Introversion
• Gender- Females
• Age- Younger children
• Time interval- Reconstruction and retrieval induced forgetting
EXPERIMENT-1
Subjects: 120 students of U.G. and P.G. classes, aged 18 to 25 years (60 males, M=23 years and 2 months and 60 females, M=22 years and 8 months).
Materials: 1. Witnessed event in two modes of presentation: One was staged and the
other was its video recorded clip.
2. A memory test consisting 20 items regarding details of the event.
Design: 3 (Consistent, Misleading and No Post-event Information)x2 (Staged Event and Video Clipped Event)x2 (Males and Females) factorial design.
Procedure:
Phase-1. Exposure to the witnessed event. Phase-2. Introduction of post-event information. Phase-3. Memory test.
Method
Table 2: Treatment Level-wise Mean Memory Scores and SDs
TREATMENT LEVELSMEMORY
SCORES
MEAN SDs
A Types of Post-Event Information
1. Consistent 15.70 2.03
2. Misleading 5.35 1.59
3. No 8.65 3.02
B Modes of Event Presentation
1. Staged Event 9.43 5.40
2. Video Clipped Event 10.37 4.33
C Gender
1. Males 10.03 4.10
2. Females 9.77 5.61
Table 3: Summary of 3 2 2 Factorial Analysis of Variance for Memory Scores
Source of Variation SS df MSS Fp Level of
Significance
A(Types of Post-Event Information) 2236.20 2
1118.10
414.68
.0001
B(Modes of Event Presentation)
26.13 1 26.13 9.69 .002
C(Gender)
2.13 1 2.13 0.79 .376
A B 54.87 2 27.43 10.17 .0001
B C 128.13 1 128.13 47.52 .0001
A C 78.87 2 39.43 14.63 .0001
A B C 33.27 2 16.63 6.17 .003
Within Treatments (Error) 291.20 108 2.70
Total 2850.80 119
Figure 2 : Mean Memory Scores as a Function of Types of Post-Event Information and gender
0
2
4
6
8
10
12
14
16
18
20
Consistent Misleading No
Types of Post-Event Information
Me
an
Me
mo
ry S
co
res
Staged Video Clipped
Figure 3 : Mean Memory Scores as a Function of Modes of Event Presentation and Gender
0
2
4
6
8
10
12
14
16
18
20
Staged Video Clipped
Modes of Event Presentation
Mean
Mem
ory
Sco
res
Male Female
Figure 4 : Mean Memory Scores as a Function of Types of Post-Event Information and Gender
0
2
4
6
8
10
12
14
16
18
20
Consistent Misleading No
Types of Post-Event Information
Me
an
Me
mo
ry S
co
res
Male Female
EXPERIMENT-2
Subjects: 60 students of Under Graduate and Post Graduate classes, aged 18 to 25 years (30 males, M=22 years and 5 months and 30 females, M=22 years and 11 months)
Materials:
1. Witnessed events of two emotionality, one of pleasant emotion and another of unpleasant emotion.
2. Two memory tests consisting 20 items regarding details of the two events.
Design: 3 (Consistent, Misleading and No Post-Event Information) 2 (Males and Females) 2 (Event of Pleasant and Unpleasant emotion) mixed factorial.
Procedure:
Phase-1. Exposure to the witness event.
Phase-2. Introduction of post-event information.
Phase-3. Memory test.
Method
Table 5: Treatment Level-wise Mean Memory Scores and SDs.
TREATMENT LEVELS
MEMORY SCORES
MEAN SD
A Types of Post-Event Information
1. Consistent 15.90 1.92
2. Misleading 7.95 2.28
3. No 10.48 1.72
B Gender
1. Males 11.13 3.57
2. Females 11.75 4.15
C Event Emotionality
1. Pleasant 12.38 3.66
2. Unpleasant 10.50 3.87
Table 6: Summary of 3 2 2 Mixed Factorial Analysis of Variance for Memory Scores.
Source of VariationSS df MSS F
p Level of Significance
Between SS 1513.10 59
A(Types of Post-Event
Information)1320.12 2 660.0585 218.35 .0001
B(Gender)
11.41 1 11.408 3.77 .057
A B 18.32 2 9.1585 3.03 .057
Ss Within groups (Error I) 163.25 54 3.023
Within SS 268.50 60
C(Event Emotionality)
106.41 1 106.408 45.28 .0001
A C 30.02 2 15.0085 6.34 .0001
B C 0.41 1 0.408 0.17 .678
A B C 4.82 2 2.4085 1.04 .366
C x Ss within groups (Error II)
126.85 54 2.35
Total 1781.59 119
Figure 6 : Mean Memory Scores as a Function of Types of Post-Event Information and Event
Emotionality
0
2
4
6
8
10
12
14
16
18
20
Consistent Misleading No
Types of Post-Event Information
Mean
Mem
ory
Sco
res
Pleasant Unpleasant
Conclusions
• Misleading post-event information leads to poor eyewitness memory retention
(Misinformation effect)• Subjects exposed to staged event and unpleasant event
show higher level of suggestibility to post-event information
(Cue-utilizing hypothesis and weapon focusing)
• Females were more susceptible to accept post-event information about the staged event than the video-clipped event in comparison to males
(Gender related eyewitness tasks in Indian social setting)