The Effects of Evidence, Coherence and Credentials on Jury Decision-Making in Child Sexual Abuse Trials

Abstract

Expert testimony is being used increasingly in child sexual assault cases. This study extended a prior study that examined factors related to expert testimony (evidence strength, coherence and credentials of the expert) on ratings of guilt and overall verdict. Specifically, we replicated our prior study but with two modifications: we used community samples as opposed to university students, and participants made their decisions in groups of 12 (as in the case of juries where one decision represents the overall group) rather than having participants decide and submit their verdicts and guilt ratings individually. Consistent with the prior (less ecologically valid) study, credentials of the expert had negligible impact. Evidence that was high in strength elicited a relatively high guilt rating even when the testimony was low in coherence. Further, it appears that when participants deliberate in a group (as in the case of juries) they are more conservative in their judgements (i.e., they are less likely to give a guilty verdict) compared to individual jurors who make their decisions alone. These findings suggest that caution must be exercised when drawing conclusions about the generalisability of prior research findings where participants did not engage in group deliberation.

Key words:

• child sexual abuse
• evidence
• expert testimony
• jury decision-making
• witness credibility