1 - Introduction

Summary

Why do jurors who hear the same evidence frequently disagree on the proper verdict? When and how do preexisting prejudices and attitudes influence jurors’ decisions? How do jurors comprehend and apply instructions on the presumption of innocence and the standard of proof? How does a juror resolve conflicts that arise when his or her sense of justice dictates an outcome that conflicts with the appropriate verdict based on the juror's evaluation of the evidence? What types of decisions can we trust jurors to make well and which decisions are beyond the reasoning powers of nonexpert jurors? The authors of the present volume address these questions. But, in contrast to traditional legal scholars and authorities, their approach is scientific. This means that their overarching goal is to create a general, unified, empirically-based theory of the juror's thought processes and behavior.

Each of the major chapters in the present collection proposes a model of juror decision making. Each model is an explicit, precise, internally consistent set of statements about mental representations and processes that would be necessary to predict and explain the decisions made by jurors in realistically complex criminal trials. A basic convention of scientific discourse is that theoretical statements be public. Some of the models are in the form of mathematical equations and assumptions about their application, some in the form of computer programs that perform portions of the juror decision task, and some in the form of verbal statements.