But does lack of sleep also make you less moral?
It appears so, according to a new study that tested 71 Norwegian naval and army officer cadets. Prior to being sleep-deprived, the cadets were asked to take the Defining Issues Test, an examination based on Lawrence Kohlberg’s stages of moral development. Those who score well on the test demonstrate the ability to think abstractly about moral decisions, to effectively weigh harm vs. benefit. Those who score poorly tend to give self-serving answers or strictly follow the rules without evaluating the consequences.
When rested (averaging eight hours of sleep a night), a number of the cadets had high scores. But under simulated combat conditions (2.5 hours of sleep a night over five days), the scores for those same cadets dropped significantly. They relied on the rules to make moral judgments and more or less stopped thinking for themselves. Incidentally, the cadets who scored poorly when rested also scored poorly when tired.
From the paper:
These findings complement previous studies which suggested that partial sleep deprivation in particular affects cognitive processes that involve complex integrating tasks where flexibility, innovation, or plan revision is required.
Could sleep deprivation have played a role in abuses like those at Abu Ghraib, where the guards who were held responsible were working the night shift? That’s me asking, not the authors, but they do write that “a possible consequence of moral decay may be disproportionate use of power.”
One theory of sleep holds that people build up “sleep debt” that has to be repaid over long periods of time. If that’s true, perhaps some of us aren’t really bad—maybe we just need a few more naps.
(The abstract is here. The paper, “The Impact of Partial Sleep Deprivation on Moral Reasoning in Military Officers,” was published in Sleep. The authors are Olav Kjellevold Olsen, Ståle Pallesen,and Jarle Eid.)