The Effects of Limited Sleep on Cognitive Self-Regulation
Sally Redden, Shelly Tang, Leigh Mingle
Faculty Sponsor: Jacqueline Muir-Broaddus
Adolescents tend to be sleep-deprived as a group, yet inadequate sleep is known to have measurable effects on academic achievement and emotional experience (Wolfson & Carskadon, 1998). Less is known, however, about the effects of inadequate sleep on underlying cognitive processes, particularly the executive functions (EF) and self-regulation. Self-regulation, the ability to control emotions, thoughts, and impulses (Baumeister, 2003), is a limited resource that is depleted through repeated use (Muraven et al., 1998). This depletion is greatest on tasks that require EF (Schmeichel et al., 2003), perhaps because self-regulation and EF draw on the same pool of resources (Baumeister, 2003). Given that sleep deprivation impairs performance on EF tasks (Nilsson et al., 2004) it is likely that sleep deprivation accentuates the negative impact of engaging in self-regulation. Hence, the purpose of this study is to investigate whether variations in sleep impair executive functioning and magnify the negative effects on executive functioning of engaging in self-regulation.
College students completed two 45-minute testing sessions, once following one night of limited sleep (< 4 hours) and once following one night of adequate sleep (> 7 hours). Measures included a questionnaire and four published tests of EF (Tower of London, Stroop, Operation Span, and WAIS-III letter-number sequencing). The Stroop was repeated at the end of the session to determine if the effects of self-regulation depletion are greater with limited sleep.
Repeated measures ANOVAs revealed no significant differences in executive functioning between the sleep and no sleep conditions. Also, there were no differences between the first and second administrations of the Stroop test. One interpretation of these findings is that a single episode of sleep deprivation may not be enough to cause performance deficits during a short testing session, perhaps because students can compensate with increased effort. It is possible that multiple nights with limited sleep would significantly impair performance, especially if the tasks required sustained mental effort. Further research is needed to test this hypothesis.