Expert Psychological Testimony

Abstract

Psychologists serve as expert witnesses in criminal and civil cases and testify about a wide range of clinical, cognitive, developmental, industrial-organizational, biological, and social psychological topics. We review the topics about which psychologists offer testimony, the rules governing the admissibility of expert testimony, and contemporary research on expert testimony. With respect to the latter, we review research concerning the need for, appropriateness of, and effect of expert testimony. We discuss research pertaining to admissibility issues, including the effect of changes in admissibility criteria on admissibility decisions and judge and juror sensitivity to the quality of scientific psychological research. Because judges and jurors lack sensitivity to variations in expert evidence quality and common safeguards do not appear to increase sensitivity to research flaws, additional research is needed to identify methods of assisting fact finders who must evaluate expert testimony.