The Science of Persuasion: Practical Insights from Research on Expert Witness Effectiveness and Jury Decision-Making Harnessing the Science of Persuasion for Expert Witness Testimony Tess M.S. Neal, Ph.D. National Science Foundation Postdoctoral Fellow, University of Nebraska Public Policy Center Incoming Assistant Professor (Fall 2015), Arizona State University, New College of Interdisciplinary Arts & Sciences Lincoln, NE Margaret Bull Kovera, Ph.D. Editor-in-Chief, Law and Human Behavior Professor of Psychology John Jay College of Criminal Justice New York, NY INTRODUCTION Expert testimony is intended to assist jurors with their task of evaluating trial evidence by providing them with information that is not commonly known by laypeople but is relevant for making the decision confronting the jury. Experts may also offer an opinion about a crucial issue in the case based on their specialized knowledge or skills. When testifying about their area of expertise or about the opinion that they have formed after reviewing case facts, experts are essentially communicating information to the jury with the intent of influencing their decision in a case. Thus, expert testimony can be construed as a persuasive message delivered by an expert (the source) to the jury (the audience). We begin this article by introducing theories of persuasion, then briefly introduce jury methodology to equip the reader to better understand the science of studying jurors’ evaluation of expert testimony. We then discuss relevant studies that have examined persuasion in the expert witness context, and end with practical implications for strategies attorneys can use for witness selection and preparation.