An Examination of Circadian Impacts on Judgments

Many people suffer from insufficient sleep and the adverse effects of sleep deprivation or chronic sleep restriction are well documented. Relatedly, recent research has shown that people’s judgments and decisions can be affected by circadian timing. We contributed to this literature by examining time-of-day impact on people’s judgments about hypothetical legal scenarios, hypothesizing that participants responding at a suboptimal time of day (3-5 AM) would give higher guilt ratings and be less sensitive to case information (e.g., evidence strength) than participants responding at a more optimal time of day (2-4 PM). Despite the fact that the time-of-day manipulation successfully influenced participants’ self-reported alertness levels, the time-of-day did not affect guilt judgments or sensitivity to case information. Exploratory analyses found that chronic daytime sleepiness coupled with suboptimal time-of-day impacted participants’ judgments. This adds to the broader literature on how extraneous factors may impact probability assessments, and these results suggest that circadian timing might differentially affect people depending on other contributing factors. Key Words: Sleep deprivation; Circadian mismatch; Judgments; Bayesian choice