Shaping interpretations: the role of evidence presentation and evidence ambiguity in mock juror decisions

Abstract

Jurors are expected to make rational, evidence-based decisions in criminal trials. However, research shows that juror judgments are often influenced by extraneous factors unrelated to the evidence, which can undermine the fairness of the justice system. This study investigated how evidence presentation format (multimedia vs. text-only) and evidentiary ambiguity (clear vs. ambiguous) interacted to influence juror guilt judgments, hypothesizing that multimedia presentations would promote deeper processing, leading to greater sensitivity to evidence clarity. A mixed factorial experimental design was employed with 77 university participants recruited online, manipulating presentation format between subjects and evidence ambiguity within subjects. Results demonstrated that multimedia presentations were rated lower in terms of guilt, revealing a significant interaction between presentation format and evidence ambiguity. Participants exposed to multimedia presentations rated guilt lower for ambiguous evidence compared to clear evidence, indicating enhanced discrimination. Conversely, text-only participants rated guilt higher for ambiguous evidence, suggesting greater reliance on heuristic cues. The findings partially confirm the hypothesis: multimedia presentations facilitated deeper processing and sensitivity to evidence clarity, while text-only formats led to increased heuristic reliance under ambiguity. Enhancing juror engagement through multimedia presentations may help safeguard justice by supporting more accurate evaluations of complex evidence. Future studies should examine the effects of physical and emotional courtroom environments, incorporate directly relevant multisensory evidence, and consider factors such as cognitive load to better understand how presentation format and ambiguity influence juror cognition and verdicts.