Faculty and Staff

Two experiments examined how mock jurors’ beliefs about three factors known to influence eyewitness memory accuracy relate to decision-making (age of eyewitness and presence of weapon in Study 1, length of eyewitness identification decision time in Study 2). Psychology undergraduates rendered verdicts and evaluated trial participants after reading a robbery-murder trial summary that varied eyewitness age (6, 11, 42, or 74 years) and weapon presence (visible or not) in Study 1 and eyewitness decision length (2-3 or 30 seconds) in Study 2 (n=200 each). The interactions between participant belief about these variables and the manipulated variables themselves were the heart of this study. Participants’ beliefs about eyewitness age and weapon presence interacted with these manipulations, but only for some judgments – verdict for eyewitness age and eyewitness credibility for weapon focus. The exploratory meditational analyses found only one relation: juror belief about eyewitness age mediated the relation between eyewitness age and credibility ratings. These results highlight a need for juror education and specialized voir dire in cases where legitimate concerns exist regarding the reliability of eyewitness memory (e.g., child eyewitness, weapon presence during event, long eyewitness identification time). If erroneous juror beliefs can be corrected their impact may be reduced.

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.

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 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.