The Effects of 53 Hours of Sleep Deprivation on Moral Judgment

STUDY OBJECTIVES: Functional neuroimaging studies suggest a prominent role for the medial prefrontal cortex in the formation of moral judgments. Activity in this region has also been shown to decline significantly during sleep loss. We therefore examined the effects of 2 nights of sleep deprivation on several aspects of moral judgment. DESIGN: Participants made judgments about the "appropriateness" of various courses of action in response to 3 types of moral dilemmas at rested baseline and again following 53 hours of continuous wakefulness. SETTING: In-residence sleep laboratory at the Walter Reed Army Institute of Research. PARTICIPANTS: Twenty-six healthy adults (21 men, 5 women). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Compared to baseline, sleep deprivation resulted in significantly longer response latencies (suggesting greater difficulty deciding upon a course of action) only for Moral Personal (i.e., emotionally evocative) dilemmas, whereas response times to Moral Impersonal (less emotionally evocative) and Non Moral dilemmas did not change significantly with sleep loss. The effect of sleep deprivation on the willingness to agree with solutions that violate personally held moral beliefs was moderated by the level of emotional intelligence, as measured by the Bar-On EQ-i. Persons high in emotional intelligence were less susceptible to changes in moral judgments as a function of sleep loss. CONCLUSIONS: These findings suggest that sleep deprivation impairs the ability to integrate emotion and cognition to guide moral judgments, although susceptibility to the effects of sleep loss on this ability is moderated by the level of emotional intelligence.