Sleep deprivation is particularly problematic for decision-making involving uncertainty and unexpected change, according to a study published in the May issue of Sleep. Twenty-six subjects were randomized to 62 hours of total sleep deprivation or to a control condition. Researchers conducted performance testing at baseline, after two nights of total sleep deprivation or rested control, and following two nights of recovery sleep. Participants performed a decision task that involved initial learning of response sets and subsequent reversal of contingencies. Working memory and psychomotor vigilance tests also were administered. Sleep-deprived subjects had difficulty with initial learning of stimuli sets and profound impairment adapting to reversal. Skin conductance responses to outcome feedback were diminished, indicating blunted affective reactions to feedback accompanying sleep deprivation. Sleep deprivation did not significantly affect working memory scanning performance.
—Kimberly Williams