Improving Juror Assessments of Forensic Testimony and Its Effects on Decision-Making and Evidence Evaluation

Devon E. LaBat, Deborah Goldfarb, Jacqueline R. Evans, Nadja Schreiber Compo, Cassidy J. Koolmees, Gerald LaPorte, Kevin Lothridge

We explored whether an educational forensic science informational (FSI) video either alone or with specialized jury instructions would assist mock jurors in evaluating forensic expert testimony. We predicted that the FSI video would help participants distinguish between low-quality and high-quality testimony, evidenced by lower ratings of the testimony and the expert when the testimonial quality was low compared with when it was high. Jury-eligible adults (N = 641; Mage = 38.18 years; 77.4% White; 8.1% Latino/a or Hispanic; 50.1% male) watched a mock trial and were randomly assigned to a no-forensic-evidence control condition or to a test condition (i.e., participants either watched the FSI video before the trial or did not and either received specialized posttrial instructions or did not). In the test conditions, a forensic expert provided low-quality or high-quality testimony about a latent impression, and participants rated the expert, their testimony, and the forensic evidence. All participants rendered verdicts. The presence of the FSI video interacted with testimonial quality on ratings of the expert and forensic testimony: In the video-present condition, participants rated the expert in the low-quality testimony condition lower than did participants in the high-quality testimony condition (between-condition differences for credibility: d = -0.52, 95% confidence interval [CI] [-0.78, -0.27]; trustworthiness: d = -0.67, 95% CI [-0.92, -0.42]; knowledgeability: d = -0.54, 95% CI [-0.80, -0.29]). The pattern was the same for the expert's testimony (between-condition differences for convincingness: d = -0.41, 95% CI [-0.66, -0.16]; validity: d = -0.60, 95% CI [-0.86, -0.35]; presentation quality: d = -0.51, 95% CI [-0.76, -0.25]). Participants' ratings in the video-absent condition did not differ on the basis of testimonial quality (ds = -0.07-0.11). The ratings of the print evidence and verdicts were unaffected. Specialized jury instructions had no effect. The FSI video may be a practical in-court intervention to increase jurors' sensitivity to low-quality forensic testimony without creating skepticism. (PsycInfo Database Record (c) 2023 APA, all rights reserved).