This study examined how manipulations of likeability and knowledge affected mock jurors’ perceptions of female and male expert witness credibility (N=290). Our findings extend the person perception literature by demonstrating how warmth and competence overlap with existing conceptions of likeability and credibility in the psycholegal domain. We found experts high in likeability and/or knowledge were perceived equally positively regardless of gender in a death penalty sentencing context. Gender differences emerged when the expert was low in likeability and/or knowledge; in these conditions the male expert was perceived more positively than the comparable female expert. Although intermediate judgments (e.g., perceptions of credibility) were affected by our manipulations, ultimate decisions (e.g., sentencing) were not. Implications for theory and practice are discussed.

The knowledge of experts presumably affects their credibility and the degree to which the trier of fact will agree with them. However, specific effects of demonstrated knowledge are largely unknown. This experiment manipulated a forensic expert’s level of knowledge in a mock trial paradigm. We tested the relation between low versus high expert knowledge on mock juror perceptions of expert credibility, on agreement with the expert, and on sentencing. We also tested expert gender as a potential moderator. Knowledge effects were statistically significant; however, these differences carried little practical utility in predicting mock jurors’ ultimate decisions. Contrary to hypotheses that high knowledge would yield increased credibility and agreement, knowledge manipulations only influenced perceived expert likeability. The low knowledge expert was perceived as more likeable than his or her high knowledge counterpart, a paradoxical finding. No significant differences across expert gender were found. Implications for conceptualizing expert witness knowledge, credibility, and their potential effects on juror decision-making are discussed.

Examinations of trust have advanced steadily over the past several decades, yielding important insights within criminal justice, economics, environmental studies, management and industrial organization, psychology, political science, and sociology. Cross-disciplinary approaches to the study of trust, however, have been limited by differences in defining and measuring trust and in methodological approaches. In this chapter, we take the position that: 1) cross-disciplinary studies can be improved by recognizing trust as a multilevel phenomenon, and 2) context impacts the nature of trusting relations. We present an organizing framework for conceptualizing trust between trustees and trustors at person, group, and institution levels. The differences between these levels have theoretical implications for the study of trust and that might be used to justify distinctions in definitions and methodological approaches across settings. We highlight where the levels overlap and describe how this overlap has created confusion in the trust literature to date. Part of the overlap – and confusion – is the role of interpersonal trust at each level. We delineate when and how interpersonal trust is theoretically relevant to conceptualizing and measuring trust at each level and suggest that other trust-related constructs, such as perceived legitimacy, competence, and integrity, may be more important than interpersonal trust at some levels and in some contexts. Translating findings from trust research in one discipline to another and collaborating across disciplines may be facilitated if researchers ensure that their levels of conceptualization and measurement are aligned, and that models developed for a particular context are relevant in other, distinct contexts.

This study sought to investigate the relation between expert witness likeability and juror judgments of credibility and sentencing. Two actors playing expert witnesses were trained to present themselves as high and low in likeability in a standard testimony scenario involving capital trial sentencing. The effects of extraversion and gender in mock jurors in attending to expert testimony were also examined. The dependent variables were the perceptions of the witnesses’ credibility and agreement with testimony and the participants were 210 psychology undergraduates. Likeability of expert witnesses was found to be significantly related to judgments of trustworthiness of the experts, but not related to confidence or knowledge of the experts or to the mock juror sentencing decisions. Women participants rated high likeable experts as more credible than low likeable experts; men did not. For men jurors, agreement with testimony increased as extraversion increased. However, for women jurors, agreement with testimony decreased as extraversion increased. The results suggest that likeability can be an important element of source credibility, and that attorneys and trial consultants now have an empirical foundation for addressing likeability as part of witness preparation.