Sleep deprivation affects moral judgment

March 1, 2007

Research has shown that bad sleep can adversely affect a person's physical health and emotional well-being. However, the amount of sleep one gets can also influence his or her decision-making. A study published in the March 1st issue of the journal Sleep finds that sleep deprivation impairs the ability to integrate emotion and cognition to guide moral judgments.

The study, conducted by William D.S. Killgore, PhD, and colleagues at the Walter Reed Army Institute of Research, was focused on 26 healthy adults, who made judgments about the "appropriateness" of various courses of action in response to three types of moral dilemmas on two separate occasions: at rested baseline and again following 53 hours of continuous wakefulness.

Compared to baseline, sleep deprivation resulted in significantly longer response latencies (suggesting greater difficulty deciding upon a course of action) for moral personal dilemmas.

The findings suggest that continuous wakefulness has a particularly debilitating effect on judgment and decision making processes that depend heavily upon the integration of emotion with cognition, said Killgore, adding that the results provide further support to the hypothesis that sleep loss is particularly disruptive to the ventromedial prefrontal regions of the brain, which are important for the integration of affect and cognition in the service of judgment and decision making.

"Most of us are confronted with moral dilemmas nearly every day, although the majority of these choices are minor and of little consequence," said Killgore. "Although such decisions are inextricably steeped in social, emotional, religious and moral values, and their correct courses of action cannot be determined through scientific inquiry, it is well within the realm of science to ask how the brain goes about solving such dilemmas and what factors, whether internal or external to the individual, contribute to the judgments and decisions that are ultimately reached."

According to Dr. Killgore, these findings do not suggest that sleep deprivation leads to a decline in "morality" or in the quality of moral beliefs, but a latency to respond and the change in the leniency or permissiveness of response style as evidenced by the tendency to decide that particular courses of action were "appropriate" before and after sleep loss.

"Our results simply suggest that when sleep deprived, individuals appear to be selectively slower in their deliberations about moral personal dilemmas relative to other types of dilemmas," said Killgore.

The present findings may have implications for those in occupations that frequently require periods of extended sleep loss and in which real-world moral dilemmas may be encountered (e.g., emergency medical services, military personnel in combat, fire/rescue workers), noted Killgore. When sleep deprived, such personnel may experience greater difficulty reaching morally based decisions under emotionally evocative circumstances and may be prone to choosing courses of action that differ from those that they would have chosen in a fully rested state, added Killgore.

Experts recommend that adults get seven-to-eight hours of sleep on a nightly basis.

Those who think they might have a sleep disorder are urged to discuss their problem with their primary care physician, who will issue a referral to a sleep specialist.

Source: American Academy of Sleep Medicine