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 chapter integrates from cognitive neuroscience, cognitive psychology, and social psychology the basic science of bias in human judgment as relevant to judgments and decisions by forensic mental health professionals. Forensic mental health professionals help courts make decisions in cases when some question of psychology pertains to the legal issue, such as in insanity cases, child custody hearings, and psychological injuries in civil suits. The legal system itself and many people involved, such as jurors, assume mental health experts are “objective” and untainted by bias. However, basic psychological science from several branches of the discipline suggest the law’s assumption about experts’ protection from bias is wrong. Indeed, several empirical studies now show clear evidence of (unintentional) bias in forensic mental health experts’ judgments and decisions. In this chapter, we explain the science of how and why human judgments are susceptible to various kinds of bias. We describe dual-process theories from cognitive neuroscience, cognitive psychology, and social psychology that can help explain these biases. We review the empirical evidence to date specifically about cognitive and social psychological biases in forensic mental health judgments, weaving in related literature about biases in other types of expert judgment, with hypotheses about how forensic experts are likely affected by these biases. We close with a discussion of directions for future research and practice.

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.