The right to a jury trial is a fundamental check on “arbitrary methods of prosecuting pretended offenses, and arbitrary punishments upon arbitrary convictions.” THE FEDERALIST PAPERS, No. 83 at 543 (A. Hamilton)(E.Earle ed. 1937). In Duncan v. Louisiana, 391 U.S. 145, 155-56(1968) the United States Supreme Court emphasized that the primary purpose of a jury is to act as an “inestimable safeguard” against a “biased or eccentric judge.”
Now science may be validating the faith our Founding Fathers put in juries.
In a study published recently in Proceedings of the National Academy of Sciences (PNAS), http://www.pnas.org/content/112/24/7460.abstract, finds that groups are consistently more accurate in distinguishing truths from lies than one individual.
In “Group Discussion Improves Lie Detection,” by University of Chicago Booth School of Business Professor Nicholas Epley and Chicago Booth doctoral student Nadav Klein, the researchers designed four experiments in which groups consistently distinguished truth from lies more accurately, demonstrating that the group advantage in lie detection comes through the process of group discussion, not the product of a “wisdom of crowds” effect. Groups were not simply maximizing the small amounts of accuracy contained among individual members but were instead creating a unique type of accuracy altogether. Group discussion alters how individuals evaluate a given statement to increase accuracy. Because individuals already possess some accuracy in detecting truths, unique improvement from group discussion would increase accuracy in detecting lies.
“We find a consistent group advantage for detecting small ‘white’ lies as well as intentional, high-stakes lies told for personal gain,” says Epley. “This group advantage seems to come through the process of group discussion rather than statistical aggregation of individual opinions.”
The available psychological and sociological research and analysis clearly indicates that a jury is a more reliable factfinder than a judge. A judge is more likely to have a cognitive bias against a defendant and a 12-person jury has the benefit of a diverse range of experience that enhances fairness. Ballew v. Georgia, 435 U.S. 223, 232-39(1978)(opinion of Blackmun, J.)(Research findings that “raise doubts about the accuracy of the results achieved by smaller and smaller panels” of factfinders used to decide that a five member jury does not satisfy the constitutional jury trial guarantee.); Lambright v. Stewart, 191 F.3d 1181, 1184(9th Cir. 1999)(lower number of jurors leads to inaccurate factfinding and incorrect application of the common sense of the community to the facts); Guggenheim & Hertz, Reflections on Judges, Juries, and Justice: Ensuring the Fairness of Juvenile Delinquency Trials, 33 Wake Forest L. Rev. 553, 571-82(1998).
The natural extension to the Ballew court’s finding that a five-member jury is not reliable is that one factfinder is even worse – especially one that must deal with a court calendar and make factual findings. Ballew, 435 U.S. at 232-33(“[A] positive correlation exists between group size and the quality of both group performance and group productivity.”); Guggenheim & Hertz, at 578. Simply put, one judge cannot compete with a 12-person jury for reliability of the factfinding function that is “critical to the accurate application of the common sense of the community to the facts.” Ballew, 435 U.S. at 234.