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Scientific evidence, Expert testimony, MtDNA evidence, Jury trial innovations, Jury competence, Jury comprehension of scientific evidence, State v. Pappas, Mitochondrial DNA, Jury MtDNA Study, Judge MtDNA Study


Evidence | Judges | Science and Technology Law


The rise in scientific evidence offered in American jury trials, along with court rulings thrusting judges into the business of assessing the soundness of scientific evidence, have produced challenges for judge and jury alike. Many judges have taken up the duty of becoming “amateur scientists.” But what about juries? Surely they too could benefit from assistance as they attempt to master and apply complex testimony about scientific matters during the course of a trial. Concerns about the jury’s ability to understand, critically evaluate, and employ scientific evidence in deciding complex trials have led to many suggestions for reform.

This article begins by summarizing what we currently know about how juries respond to scientific evidence. Then, it describes a mock jury experiment that my research collaborators and I conducted to examine whether trial reforms could improve jurors’ comprehension and appropriate use of scientific evidence, specifically mitochondrial DNA (mtDNA) evidence. This article also reports the intriguing findings of a new study involving state and federal judges who watched clips of the same mtDNA mock trial and answered some of the same questions as the jurors. The article concludes with a consideration of the implications of the judge and jury mtDNA studies for three broad remedies often suggested to deal with jury trials involving complex cases: (1) having judges instead of juries decide the cases; (2) using “blue ribbon” juries of highly educated citizens; and (3) implementing trial innovations.

Publication Citation

Published in: Journal of Law and Policy, vol. 16, no. 1 (2007).