Improving juror assessments of forensic testimony and its effects on decision-making and evidence evaluation

Abstract

Objective: 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.

Hypotheses: 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.

Method: Jury-eligible adults (N = 641; M_age = 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.

Results: 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.

Conclusion: 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) 2024 APA, all rights reserved).