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‘The innocent v the fickle few’: how jurors understand random-match-probabilities and judges’ directions when reasoning about DNA and refuting evidence

Cowley-Cunningham, Michelle orcid logoORCID: 0000-0002-1997-6009 (2017) ‘The innocent v the fickle few’: how jurors understand random-match-probabilities and judges’ directions when reasoning about DNA and refuting evidence. International Journal of Forensic Science & Criminal Investigation, 3 (5). ISSN 2476-1311

Abstract
DNA evidence is one of the most significant modern advances in the search for truth since the cross examination, but its format as a random-match-probability makes it difficult for people to assign an appropriate probative value [1]. While Frequentist theories propose that the presentation of the match as a frequency rather than a probability facilitates more accurate assessment [2], Exemplar-Cueing Theory predicts that the subjective weight assigned may be affected by the frequency or probability format, and how easily examples of the event, i.e., ‘exemplars’, are generated from linguistic cues that frame the match in light of further evidence [3]. This paper presents two juror research studies to examine the difficulties that jurors have in assigning appropriate probative value to DNA evidence when contradictory evidence is presented. Study 1 showed that refuting evidence significantly reduced guilt judgments when exemplars were linguistically cued, even when the probability match and the refuting evidence had the same objective probative value. Moreover, qualitative reason for judgment responses revealed that interpreting refuting evidence was found to be complex and not necessarily reductive; refutation was found indicative of innocence or guilt depending on whether exemplars have been cued or not. Study 2 showed that the introduction of judges’ directions to linguistically cue exemplars, did not increase the impact of refuting evidence beyond its objective probative value, but less guilty verdicts were returned when jurors were instructed to consider all possible explanations of the evidence. The results are discussed in light of contradictory frequentist and exemplar-cueing theoretical positions, and their real-world consequences.
Metadata
Item Type:Article (Published)
Refereed:Yes
Uncontrolled Keywords:DNA Evidence; Random-Match-Probability; Juror Decision-Making; Exemplar-Cueing Theory; Frequentist Theories; Reasoning and Rationality
Subjects:Biological Sciences > Genetics
Humanities > Biological Sciences > Genetics
Medical Sciences > Psychology
Social Sciences > Law
Social Sciences > Mass media
DCU Faculties and Centres:DCU Faculties and Schools > DCU Business School
Publisher:Juniper Publishers
Official URL:https://doi.org/10.19080/JFSCI.2017.03.555601
Copyright Information:© 2017 The Authors.
Funders:Socio-legal Studies Association Small Grant Scheme
ID Code:29490
Deposited On:24 Jan 2024 16:49 by Michelle Cowley-Cunningham . Last Modified 24 Jan 2024 16:49
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