The effect of trauma education judicial instructions on decisions about complainant credibility in rape trials.

Abstract

Judicial instructions are a practical, but not always effective, way of providing education to jurors to help them evaluate the evidence given by witnesses. In this research, we investigated whether jurors comprehended and applied common judicial instructions intended to help the jury accurately evaluate the evidence given by a rape complainant without being influenced by legally irrelevant stereotypes about the complainant's emotional demeanor. We hypothesized that a trauma education instruction would improve participants' trauma knowledge and reduce participants' reliance on stereotypes to evaluate the complainant's evidence compared with standard witness instructions given about evaluating the credibility of witnesses at trial. In Study 1 (N = 165), participants were asked to read one of three judicial instructions (trauma education, stereotype education, or standard) and their comprehension of the instruction was assessed. In Study 2 (N = 1085), participants were asked to decide a typical adult rape case in which the complainant was distressed or unemotional after receiving one of three types of judicial instructions (no specific witness instruction, standard witness, or trauma education instruction). Across both studies, we found that trauma education instructions improved participants' trauma knowledge. Unexpectedly, we found that both the standard witness and trauma education instructions reduced the extent to which participants were influenced by stereotypes in evaluating the complainant's credibility but reduced perceptions of the complainant's credibility. These findings highlight the need for ongoing evaluation of educational instructions to ensure that they operate as intended to help jurors make accurate decisions in criminal trials.

Handle with care: Jury deliberation and demeanour-based assessments of witness credibility

“…The evidence relating to judicial directions is not, however, universally positive. Nitschke et al (2022), for example, found that a judicial instruction about the likely effects of trauma on witness testimony resulted in jurors rating all complainer testimony as less credible, regardless of the degree of emotion the complainer displayed. The authors speculate that this was because the instruction left jurors uncertain about how they should evaluate credibility, resulting in a general scepticism towards the witness.…”