Doctoral Dissertation Research: Improving Juror Assessments of Causality

Arizona State University, Scottsdale AZ

Investigators

Abstract

Doctoral Dissertation Research: Improving Juror Assessments of Causality NSF Proposal Number #0616439 PI: Michael Saks Co-PI: Nicholas Schweitzer Abstract Legal scholars have long raised doubts over the ability of the lay juror to properly evaluate scientific testimony. These scholars' concerns are underscored by, what many perceive to be, an alarming level of "scientific illiteracy" among Americans. The available empirical research suggests that the average juror has considerable difficulty comprehending scientific evidence, and in particular, making correct causal inferences from probabilistic or statistical data. Unfortunately, as litigation involving scientific testimony increases, jurors will be called upon to make these judgments with increasing frequency. However, there is evidence among the social science literature demonstrating that people can be taught to make more accurate judgments. For example, a general education in the formal rules of statistics has been shown to improve the everyday-problem reasoning ability of individuals with a variety of educational levels. Furthermore, the effects of a general training in statistics can be seen when the everyday problem encountered is completely unrelated to the context of the training, and even when the training is very brief (e.g., 25 minutes). Building on these findings, the proposed research develops a jury education technique that should improve jurors' ability to make causal inferences based on epidemiological / statistical data. This technique is designed in such a way that it could be used under a wide variety of circumstances, and is not specific to one trial or type of trial. Our research will be conducted in a series of studies. We will begin by examining the ability of our participants to make correct assessments of causality based on evidence that varies in its support of a causal relationship. This first study is unique among research in this area, in that it will not only assesses the overall abilities of our participants, but will also explore various aspects of causal relationships, and determine the aspects to which individuals attune when making causal assessments (and perhaps more importantly, it will identify the aspects that are overlooked). Next, we will use the findings from the first study to create a short educational program designed to improve jurors' understanding of causality, and, in turn, improve their ability to make proper assessments of causality. Finally, the educational program will be tested on both a college-educated and general-population sample using a series of mock-trials that involve causal issues with epidemiological / statistical evidence. Should the educational technique prove to be successful, many of the concerns regarding jurors' competence in evaluating certain types of statistical evidence could be allayed. And in addition, we hope that our educational program will not only make people better jurors, but also make them better consumers of science. By teaching the basic principles of cause-and-effect relationships, we hope to strengthen people's ability to critically evaluate scientific claims that they may hear, regardless of whether those claims originate from an expert witness, a teacher or the media.