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.

There is substantial controversy over the extent to which social science should be used in jury selection. Underlying the debate are two competing interests in the make-up of a jury: a privilege to strike prospective jurors on subjective grounds, which supports scientific jury selection, and a collective interest of citizens to be free from exclusion from jury service, which does not. While the incommensurability of the interests precludes resolution of the controversy in the abstract, specific solutions are possible. Using the example of selection of jurors based upon their respective levels of extraversion, we describe how the competing interests frequently do not apply to concrete cases. In the subsequent analysis, we show that, rhetoric notwithstanding, a normative preference for adhering to tradition and institutional inertia are the primary instrumental considerations for determining whether peremptory challenges based upon personality traits like extraversion ought to be allowed. Consistent with this analysis, we conclude that the practice of striking jurors based upon estimates of such personality traits is appropriate.

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 essential tasks for an expert witness are to be prepared, to be effective and credible on the stand, and to manage well the demands of cross-examinations. Most novice experts are excessively anxious about their testimony. Effective experts are well-oriented to the legal and scientific context of court testimony. This chapter reviews research-backed tips for preparing for expert testimony.

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.

Self-Efficacy Theory (SET; Bandura, 1986, 2000) has generated research and practice ramifications across areas of psychology. However, self-efficacy has yet to be assessed in a legal context. The present paper juxtaposes self-efficacy with self-confidence in terms of theoretical foundations and practical implications, with attention to the area of witness testimony. It is concluded that the concept of witness self-efficacy possesses thorough theoretical grounding as a potential target for witness preparation. As such, we put forth an integrated model of witness preparation featuring self-efficacy bolstering techniques within an established witness training framework.

Despite the application of Self-Efficacy Theory (Bandura, 1977, 2000) to many areas of psychology, there is a lack of research on self-efficacy in the ability to testify in court. The present study fills this gap by incrementally developing the construct of Witness Self-Efficacy and establishing its psychometric properties. Study I featured exploratory and confirmatory factor analyses yielding a two-factor Witness Self-Efficacy Scale (WSES). The two components are Poise and Communication Style. Study II used a second data collection to show that both WSES domains possess convergent, divergent, and predictive validity relations consistent with those expected using an SET framework. Notably, WSES components predicted perceptions of witness credibility and sentencing outcomes above and beyond witness extraversion, general self-efficacy and general self-confidence. Implications for SET and witness preparation training are discussed.