Date of Award
Edith Cowan University
Bachelor of Arts Honours
Faculty of Health and Human Sciences
Dr Adele Hills
Pryor and Buchanan (1984), using participants drawn from jury venires, showed that persons exhibiting a moderately anxious demeanour were found guilty more often than those with a low anxiety demeanour when evidence presented was balanced. In a study that used three levels of evidence (pro-acquittal, balanced and pro-conviction) and two levels of demeanour (apparently deceptive and control) Hendry, Schaffer and Peacock (1989) found that the demeanour bias only occurred at the pro-acquittal level of evidence. They had not used a criminal offence and did not provide judges instructions. Additionally conviction rates at all levels of evidence in the control condition when demeanour was manipulated increased substantially indicating that evidence levels were all being treated as pro-conviction. The present study was designed to replicate the study by Pryor and Buchanan and extend it to the three levels of evidence used by Hendry, et al. Participants were 120 (69 female, 51 male, mean age M = 38.76) jury eligible members of the general population randomly allocated as mock jurors to a 2 x 3 (demeanour x evidence) experimental factorial design. The two levels of demeanour were low anxiety and moderate anxiety while the three levels of evidence were pro-acquittal, balanced and pro-conviction. Log linear analysis was performed on dichotomous guilty / not guilty verdicts. The analysis ended with a significant overall model x2(4. N = 120) = 5.32, p = .256 this indicated the data was a good fit to the model. The interactions that remained as significant contributors to the model were verdict x evidence LR x2 (2, N = 120) = 29.2. p < .0000), and verdict x demeanour LR x2 (1, N = 120) = 11.18. p = .0008). Because all variables were entered together they constitute main effects for evidence and demeanour. These results showed that persons exhibiting a moderately anxious demeanour were found guilty more often across all levels of evidence than persons exhibiting a low anxiety demeanour.
Miller, M. (1997). Trial by Anxiety : Effects of Nervous Demeanour and Level of Evidence on Mock Jurors' Decisions. Edith Cowan University. https://ro.ecu.edu.au/theses_hons/774