The Message or the Messenger: The Impact of Explanation Satisfaction and Source Characteristics on Perceptions of Experts and Verdicts

Understanding how expert characteristics shape verdicts is critical. This study identified message (e.g., explanation satisfaction) and source characteristics (e.g., education) that predict perceived expertise and verdicts. We hypothesized an expert with more (versus less) satisfying explanations, education, and hands-on contact with the evidence would be perceived as higher in expertise, and that female experts would be perceived as lower in expertise than male experts. Further, higher expertise would predict more verdicts in line with the expert's testimony. In three mock jury studies (N = 1853), we measured (Studies 1-3) and manipulated (Study 3) explanation satisfaction. We also manipulated source characteristics (i.e., education, Studies 1-3; evidence contact, Studies 1-2; expert gender, Studies 2-3). Mock jurors reported their verdicts and perceptions of the expert. Satisfaction with the expert's explanation was the only consistent predictor of perceived expertise, and in turn, verdicts. This effect operated independently from source characteristics; expert gender, education, and more hands-on contact with the evidence did not have consistent influence on satisfaction. We found evidence that expertise cues (education, Studies 1-3; evidence contact, Studies 1-2) impacted explanation satisfaction but did not consistently influence verdicts. Our findings suggest that explanation satisfaction-not source characteristics-reliably predicted expertise and verdicts. Thus, attorneys should ensure the experts they retain can effectively communicate to jurors.