The effects of defendant nonverbal behavior in the courtroom on jury perception of guilt

Abstract

Research indicates that many extralegal factors influence jury decision making, although the effect of defendant nonverbal behavior specifically has been under researched. The aim of the present study was to examine the impact of defendant nonverbal courtroom behavior on jury guilt perception and verdict decisions. Participants (N = 96) were assigned to one of four experimental manipulations: avoidance of eye contact (n = 22), fidgeting (n = 21), sweating (n = 22), or control (n = 31). In each condition participants viewed one of four videos, in which a "defendant" displayed one of the four behaviors in response to a prosecuting attorney’s witness testifying. Although the experimental conditions did not differ significantly from the control condition on level of guilt or verdict decisions, mean scores across conditions trended in the expected direction. Confidence ratings were also analyzed and were found to play a significant role in verdict decisions, with additional analyses revealing that level of confidence was particularly discrepant in the sweating condition. The findings of this study can assist attorneys with witness preparation, as they direct defendants on how to behave throughout the trial process. However, these results also demonstrate the need to further investigate the role that nonverbal behavior plays in jury decision making and perception of guilt.