eyewitness memory

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MODES OF PRESENTATION, POST-EVENT INFORMATION, EVENT EMOTIONALITY AND GENDER AFFECTING THE EYEWITNESS ACCURACY Ari Sudan Tiwari and Chandra Bhal Dwivedi Department of Psychology Banaras Hindu University Varanasi-221005

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MODES OF PRESENTATION, POST-EVENT INFORMATION, EVENT EMOTIONALITY AND GENDER AFFECTING THE EYEWITNESS ACCURACY

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Page 1: Eyewitness memory

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

Page 2: Eyewitness memory

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

Page 3: Eyewitness memory

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

Page 4: Eyewitness memory

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

Page 5: Eyewitness memory

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

Page 6: Eyewitness memory

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

Page 7: Eyewitness memory

Figure 2 : Mean Memory Scores as a Function of Types of Post-Event Information and gender

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Consistent Misleading No

Types of Post-Event Information

Me

an

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Staged Video Clipped

Page 8: Eyewitness memory

Figure 3 : Mean Memory Scores as a Function of Modes of Event Presentation and Gender

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Staged Video Clipped

Modes of Event Presentation

Mean

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Male Female

Page 9: Eyewitness memory

Figure 4 : Mean Memory Scores as a Function of Types of Post-Event Information and Gender

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Consistent Misleading No

Types of Post-Event Information

Me

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Male Female

Page 10: Eyewitness memory

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

Page 11: Eyewitness memory

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

Page 12: Eyewitness memory

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

Page 13: Eyewitness memory

Figure 6 : Mean Memory Scores as a Function of Types of Post-Event Information and Event

Emotionality

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Consistent Misleading No

Types of Post-Event Information

Mean

Mem

ory

Sco

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Pleasant Unpleasant

Page 14: Eyewitness memory

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)

Page 15: Eyewitness memory