Educative Expert Testimony: A One-Two Punch Can Affect Jurors' Decisions (original) (raw)

2012, Journal of Applied Social Psychology

The present research examined whether different types of educative expert testimony can increase mock jurors' knowledge of problems associated with hearsay witnesses and decrease guilty verdicts. Studies 1 (N = 304 college students) and 2 (N = 196 college students) varied the length and types of expert testimony in a trial transcript. While all types of expert testimony did inform mock jurors' knowledge, guilty verdicts decreased when multiple problems with hearsay were presented. The length of the testimony had no effect on verdict. The results suggest that experts who present multiple problems with hearsay testimony are more likely to impact guilty decisions than is no expert or an expert who presents only one problem.j asp_782 535..559 Expert testimony on psychological phenomena is increasingly being sought by the courts. For example, in a recent study of expert testimony since Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993), researchers found that approximately one quarter of the experts who had testified from 1988 to 1998 were behavioral scientists (Groscup, Penrod, Studebaker, Huss, & O'Neil, 2002). The range of topics that social scientists have been called to testify about is quite large; ranging, for example, from eyewitness memory to the suggestibility of children to lineup identification and procedures. Evidence from psychological research is clearly being used in the courtroom, but what is less clear is whether such testimony affects jurors' decisions. Though many studies have shown that experts can increase jurors' knowledge (e.g., Kovera, Gresham, Borgida, Gray, & Regan, 1997), the findings have been mixed with regard to the influence on jurors' verdict decisions. Multiple studies have found that having an expert testify in the courtroom can affect jurors' verdicts (