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.

Despite advances in the scientific methodology of witness testimony research, no sound measure currently exists to evaluate perceptions of testimony skills. Drawing on self-efficacy and witness preparation research, the present study describes development of the Observed Witness Efficacy Scale (OWES). Factor analyses of a mock jury sample yielded a two-factor structure (Poise and Communication Style) consistent with previous research on witness self-ratings of testimony delivery skills. OWES subscales showed differential patterns of association with witness credibility, witness believability, agreement with the witness, and verdict decision. Juror gender moderated the impact of Communication Style, but not Poise, on belief of and agreement with the witness. Results are discussed with attention to application of the OWES to witness research and preparation training.

This review of women’s participation in the legal system as expert witnesses examines the empirical literature on the perceived credibility and persuasiveness of women compared to men experts. The effects of expert gender are complex and sometimes depend on the circumstances of the case. Some studies find no differences, some find favorable effects for women and others for men, and still others find that expert gender interacts with other circumstances of the case. The findings are interpreted through social role theory (Eagly, 1987) and the role incongruity theory of prejudice (Eagly & Karau, 2002, Eagly & Koenig, 2008). Future directions for research are identified and implications are considered for attorneys who select and prepare expert witnesses. Suggestions for men and women’s behavior as expert witnesses are provided.

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.

The effect of eye contact on credibility was examined via a 3 (low, medium, high eye contact) x 2 (male, female) between-groups design with 232 undergraduate participants. A trial transcript excerpt about a defendant’s recidivism likelihood was utilized as the experts’ script. A main effect was found: experts with high eye contact had higher credibility ratings than in the medium and low conditions. Although a confound precluded comparisons between the genders, results indicated that males with high eye contact were more credible than males with medium or low eye contact. The female experts’ credibility wasn’t significantly different regardless of eye contact. Eye contact may be especially important for males: male experts should maintain eye contact for maximum credibility.

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.