How Trauma Informed Judicial Instructions Can Influence Credibility Judgements in Mock Jurors

Abstract

Jurors have the important task of deciding whether the defendant is guilty of an offense in a criminal trial. A jury makes a subjective determination of defendant or witness credibility solely based on their testimony and is asked to refrain from using personal beliefs and common sense in making their verdict. They must apply judicial instructions, which outline the relevant law, to the evidence presented at the trial. Previous mock juror literature has illustrated that judgements of credibility are often governed by various social stereotypes and beliefs about accepted norms of behaviour. Emotional displays by a witness that fit held stereotypes during their testimony are often a strong determinant of both perceived credibility and judgements of guilt. However, the literature is heavily saturated with rape, sexual assault, and partner violence cases whereby the victim is often a female and the suspect a male. There is also little understanding about how trauma-informed judicial instructions can influence perceptions of guilt. Here we explore how emotion displayed by a female defendant in a murder case affects credibility ratings given by mock jurors. We hypothesise that trauma-informed judicial instructions can moderate stereotypes regarding emotional expression and influence verdicts given by mock jurors. The results illustrated that mock jurors rated the defendant as more credible in the high emotion (vs. the neutral emotion) condition. However, an effect of trauma-informed judicial instructions on measures of guilt was not found.