The Credibility of Witnesses

Abstract

This chapter provides an overview of the field of witness credibility. The credibility of witnesses is based on more than the substantive content of witness testimony. Ideally, the probative value of testimony by both lay and expert witnesses would contribute to understanding, would help triers of fact move toward conclusions, and would stand alone to be assessed clearly for what it is. Nonetheless, the credibility of witnesses is based on other aspects of witness testimony that make a difference in how substantive content is perceived by triers of fact. Trial consulting has emerged in the last 30 years and has a major investment in witness preparation. At its best, the trial consultation field seeks to relieve witnesses’ anxiety and intensely prepare witnesses without compromising the substantive content of their testimony. Source credibility is discussed since it has been the foundation for much of the research on the credibility of witnesses. A number of typologies have been organized to identify the component elements that make up source credibility and expert witness credibility. Research supports the conclusion that women experts are particularly likely to receive personally intrusive questions over men experts, and an evaluation of how these questions affect perceptions of experts is offered. The use of neuroscience in the courtroom has a long and controversial history and is briefly discussed, as well as its impact on juror decision-making in terms of witness credibility.