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Investigating the Accuracy of Eyewitness Identification. Presentation By Shelley West & Kamia Creelman. Literature Review. Research Importance. avoid wrongful convictions. Previous Research Investigated Identifications From Lineups. mode of presentation false identifications
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Investigating the Accuracy of Eyewitness Identification Presentation By Shelley West & Kamia Creelman
Literature Review Research Importance • avoid wrongful convictions Previous Research Investigated Identifications From Lineups • mode of presentation • false identifications • correct identifications • correct rejections • confidence level
Literature Review (cont’d) Background Information • Fallibility of eyewitness identification- 1970s • Substantial research conducted in last 20 yrs in order to establish more accurate identifications Main Focus of Research Modes of Presentation - simultaneous (all at once) - sequential (one at a time)
Literature Findings Sequential > Simultaneous Sequential Mode of Presenting Lineups produced more accurate results concerning: • false identifications • correct identifications • correct rejections • confidence levels
Overview of Present Study • Pilot Study • 48 participants, gender equal groups • Surveillance video of a man stealing a purse • questionnaire used as a distraction and to obtain demographic info • presented mug shots either simultaneously or sequentially • asked participants to rate their certainty level regarding I.D.s
Hypotheses • Sequential mode of presentation would produce fewer false I.D.s, more correct rejections, & lower certainty level than simultaneous mode of presentation • There would be no difference between the # of false I.D.s, correct rejections, & level of certainty for males & females
Experimental Design • 2X2 between-subjects factorial design • IV#1: (true) mode of presentation - simultaneous (all at once) - sequential (one at a time) • IV#2: (quasi) gender - male - female • 3 DVs - # false I.D.s - # correct rejections - level of certainty
Variables Measured (How and What) • coding sheets - # false I.D.s - # correct rejections - level of certainty - # correct I.D.s questionnaires - distraction - record gender and age
Results and Stats 1. Chi-Square Goodness of Fit Test • tested for order effects • 2 • X (6, N=48) = 4.500, p>.05) • no order effects found 2. Chi-Square Test for Independence • test effects of mode on false I.D.s, correct I.D.s, and no I.D.s • 2 • 2 • X (1, N = 48) = .000, p>.05) • no significance found
Results and Stats (cont’d) 3. Chi-Square Test for Independence • tested for correct rejections • 2 • X (1, N = 48) = .000, p>.05) • no significance found 4. 2x2 between-subjects ANOVA on certainty level • no main effect for gender (F (1, 44) = 2.81, p = .101) • no main effect for mode (F (1, 44) = .000, p > .05) • no interaction between gender and mode (F (1, 44) = .005, p>,05)
Frequency Bar Graph Legend 00 = no I.D. 01 = correct I.D. 03 = most frequent false I.D. 02,04,05,06 = other false I.D.s.
Interpretation of Results No support for Hexp. #1: • Sequential mode of presentation would produce fewer false I.D.s, more correct rejections and lower certainty level than simultaneous mode of presentation. No support for Hexp. #2: • There would be no difference between the # of false I.D.s, correct rejections, and levels of certainty for males and females.
Discussion No support for Hypotheses Does not support Literature Review Floor Effects • small sample size • too few subjects per cell • small numbers Gender Relationship • unexpected • not addressed in literature review • p = .101
Discussion Cont’d Possible factors contributing to non-signif results • surveillance video (ecological validity) • overcompensation for ceiling effects • striped shirt, ball caps Future Research • larger sample • correct rejections (suspect not in the lineup half of the time) • whether they knew # of photos they’d see • tighter control over extraneous variables • GENDER