Monash University

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Reason: Under embargo until May 2018. After this date a copy can be supplied under Section 51(2) of the Australian Copyright Act 1968 by submitting a document delivery request through your library

An analysis of the jury’s role in detecting lies, assessing credibility, and decision making

posted on 2017-01-23, 21:51 authored by Andrewartha, Danielle McPhee
This thesis synthesises a wealth of empirical and evaluative research from the fields of social, behavioural, and cognitive psychology and applies it to jury’s role within the Australian criminal justice system to analyse the jury’s abilities in relation to lie detection, assessments of witness credibility, and decision making generally. In doing so, it is acknowledged that jurors may have an innate tendency to reason in an automatic and intuitive fashion, and to rely on peripheral, cognitive heuristic cues of various kinds, which may result in the formation of early impressions that are stereotype congruent or otherwise affected by biases, and which preconceptions are extremely resistant to change throughout the course of the trial to the point of verdict even in light of even the most compelling contradictory evidence. However, it is contended that, by continuing to introduce new active jury reforms and to refine those currently in operation in the ways discussed throughout the thesis, the jury’s performance can be enhanced, and specifically with regards to deception detection, assessments of witness credibility, including evaluations of evidentiary strength and plausibility, and decision making generally through to verdict determination. Four key areas of recommendations are canvassed. The first is a consideration of identified cognitive factors, such as heuristics, or mental shortcuts, including stereotypes based on gender and race, and other extra-legal cues, such as primacy and recency effects, anchors, and primes, and proposes means of controlling the influence of such features over juror decision making. The second is an analysis of measures specifically intended to enhance the jury’s active participation in the trial process. Three key initiatives are canvassed: juror note taking and question asking, both in relation to clarification from the trial judge and questions put to witnesses and parties, and the provision of the trial transcript to jurors. The third recommendation field is premised on the acknowledgement of concerns as to jurors’ abilities with regards to comprehension as to legal concepts and instruction and their application to factual scenarios, and critique as to jurors’ capacity to deliberate effectively. Thus, these recommendations are directly related to practical means in which the jury’s performance may be enhanced in these key areas. Specifically, such measures include the use of induction exercises designed to encourage slow and effortful reasoning rather than automatic and intuitive decision making; judicial instructions and jury guides containing advice as to deliberations and how to best organise them; a mandatory judicial direction as to the meaning of ‘proof beyond reasonable doubt’; and the provision, where appropriate, of jury aids such as question trails to guide the jury’s deliberations, which are to be accompanied with relevant judicial instruction. Finally, the most controversial recommendation is explored. This is the proposed introduction into the Australian criminal justice system of an Independent Jury Facilitator (IJF). The IJF would be an accredited court officer with appropriate legal training and experience, who would assist the jury with its various functions. It is argued that the IJF would enhance the jury’s performance and streamline the trial process.


Campus location


Principal supervisor

Jonathan Clough

Year of Award


Department, School or Centre



Doctor of Philosophy

Degree Type



Faculty of Law