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

Abstract

It is unclear how effectively jurors perform their task of assessing witness credibility. Drawing on evidence from a mock jury study involving 863 mock jurors deliberating across 64 juries, and building on existing research, this paper explores juries’ reliance on demeanour. While jurors make use of factors which the research literature suggests are often appropriate credibility markers, for example external consistency of accounts, there is cause for concern over the nuance with which jurors apply those assessments in high stakes contexts. The manner in which jurors look to manner of delivery as evidence of credibility is also problematic. The paper makes the case for a more circumspect approach towards jurors’ use of demeanour assessments. At a minimum, this requires that judicial directions no longer advocate their reliability, but remind jurors of the complexities associated with such assessments and the need to treat any conclusions grounded on presentational cues with caution.

Resilience-building in Adversarial Trials: Witnesses, Special Measures and the Principle of Orality

“…Behavioural scientists highlight that, in actuality, all witnesses (not only the 'vulnerable') perform best when recalling recent events with minimal prompting, in a stress-free environment (see Spencer and Flin, 1993: ch 10-13;Roberts, 2022: 318). The ability of jurors to accurately read demeanour is highly doubted, despite its importance in adversarial theory (see Chalmers, Leverick and Munro, 2022). Plus, there are issues more generally with the reliability of witness testimony where individuals may have honestly but inaccurately perceived something and recall such in their testimony (Roberts, 2004).…”