The effects of sleep deprivation on information-integration categorization performance.

BACKGROUND Sleep deprivation is a serious problem facing individuals in many critical societal roles. One of the most ubiquitous tasks facing individuals is categorization. Sleep deprivation is known to affect rule-based categorization in the classic Wisconsin Card Sorting Task, but, to date, information-integration categorization has not been examined. STUDY OBJECTIVES To investigate the effects of sleep deprivation on information-integration category learning. DESIGN Participants performed an information-integration categorization task twice, separated by a 24-hour period, with or without sleep between testing sessions. PARTICIPANTS Twenty-one West Point cadets participated in the sleep-deprivation group and 28 West Point cadets participated in a control group. MEASUREMENTS AND RESULTS Sleep deprivation led to an overall performance deficit during the second testing session-that is, whereas participants allowed to sleep showed a significant performance increase during the second testing session, sleepless participants showed a small (but nonsignificant) performance decline during the second testing session. Model-based analyses indicated that a major contributor to the sleep-deprivation effect was the poor second-session performance of a subgroup of sleep-deprived participants who shifted from optimal information-integration strategies at the end of the first session to less-optimal rule-based strategies at the start of the second session. Sleep-deprived participants who used information-integration strategies in both sessions showed no drop in performance in the second session, mirroring the behavior of control participants. CONCLUSIONS The findings suggest that the neural systems underlying information-integration strategies are not strongly affected by sleep deprivation but, rather, that the use of an information-integration strategy in a task may require active inhibition of rule-based strategies, with this inhibitory process being vulnerable to the effects of sleep deprivation.