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.

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.

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 question as to whether the assessment of adaptive behavior (AB) for evaluations of intellectual disability (ID) in the community meet the level of rigor necessary for admissibility in legal cases is addressed. Adaptive behavior measures have made their way into the forensic domain where scientific evidence is put under great scrutiny. Assessment of ID in capital murder proceedings has garnished a lot of attention, but assessments of ID in adult populations also occur with some frequency in the context of other criminal proceedings (e.g., competence to stand trial; competence to waive Miranda rights), as well as eligibility for social security disability, social security insurance, Medicaid/Medicare, government housing, and post-secondary transition services. As will be demonstrated, markedly disparate findings between raters can occur on measures of AB even when the assessment is conducted in accordance with standard procedures (i.e., the person was assessed in a community setting, in real time, with multiple appropriate raters, when the person was younger than 18 years of age) and similar disparities can be found in the context of the unorthodox and untested retrospective assessment used in capital proceedings. With full recognition that some level of disparity is to be expected, the level of disparity that can arise when these measures are administered retrospectively calls into question the validity of the results and consequently, their probative value.

We investigated the role of moral disengagement in a legally‐relevant judgment in this theoretically‐driven empirical analysis. Moral disengagement is a social‐cognitive phenomenon through which people reason their way toward harming others, presenting a useful framework for investigating legal judgments that often result in harming individuals for the good of society. We tested the role of moral disengagement in forensic psychologists’ willingness to conduct the most ethically questionable clinical task in the criminal justice system: competence for execution evaluations. Our hypothesis that moral disengagement would function as mediator of participants’ existing attitudes and their judgments—a theoretical “bridge” between attitudes and judgments—was robustly supported. Moral disengagement was key to understanding how psychologists decide to engage in competence for execution evaluations. We describe in detail the moral disengagement measure we used, including exploratory and confirmatory factor analyses across two separate samples. The four‐factor measure accounted for a total of 52.18 percent of the variance in the sample of forensic psychologists, and the model adequately fit the data in the entirely different sample of jurors in a confirmatory factor analysis. Despite the psychometric strengths of this moral disengagement measure, we describe the pros and cons of existing measures of moral disengagement. We outline future directions for moral disengagement research, especially in legal contexts.

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.