Medical evidence of a witness' capacity to testify has long been admitted at trial. However, evidence of a witness' credibility is often limited to cross-examination because of the reluctance of courts to interfere with the function of the jury. The author explores the relation of expert testimony to the function of the jury through analysis of Federal Rule of Evidence 702, including the Rule's genesis and extension to other jurisdictions. He then explores the areas where psychological testimony of credibility would aid the fact finder in resolving testimonial contradictions based on perceptual and memory defects.
Charles L. Convis,
Testifying About Testimony: Psychological Evidence on Perceptual and Memory Factors Affecting the Credibility of Testimony,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol21/iss3/3