Deliberating science: Juries, scientific evidence and commonsense justice.

摘要

Prior empirical research examining how jurors use scientific evidence has largely relied upon a mathematical model of juror decision-making. This prior research suggests jurors are confused by probabilistic testimony and have a tendency to undervalue scientific evidence. Breaking away from the mathematical model tradition, this research utilized data from a project involving jury-eligible adults from Delaware to further examine how jurors evaluate and use statistical scientific evidence. This research project offered the unique opportunity to utilize jury deliberations as a window on lay views of science. Quantitative and qualitative analysis of questionnaire data and jury deliberations revealed a complex process in which jurors actively evaluated the scientific evidence. The most influential factor for evaluating mtDNA evidence was prior knowledge of nuclear DNA and to a lesser extent a variety of lay expectations, prior knowledge, and media exposure. Jurors had diverse expectations and evaluations of the scientific evidence. However, their individual verdict preferences and final jury verdicts were not based solely on reactions to the scientific evidence. Instead jurors' evaluations of scientific evidence interacted with their evaluations and expectations of non-scientific evidence while reflecting the constraints of the legal standards. Throughout the deliberation process, jurors called upon their notions of commonsense justice to guide them on what is just and fair.