The Effect of Sleep Deprivation on Cognitive Functioning

Abstract

This study investigated the effects of sleep deprivation on multiple domains of cognitive functioning using a mixed-methods experimental design. A total of 120 participants were randomly assigned to total deprivation, partial restriction, or control conditions, with cognitive performance assessed at baseline and post-manipulation. Quantitative analyses revealed that both partial and total sleep loss significantly impaired sustained attention on the Psychomotor Vigilance Task, reduced working memory accuracy on the N-back task, and increased Stroop interference, demonstrating executive control deficits. Subjective sleepiness ratings on the Karolinska Sleepiness Scale rose sharply in sleep-deprived groups, while reaction time variability confirmed heightened cognitive instability. Correlational analyses established strong associations between reduced sleep duration and declines across cognitive measures, and exploratory factor analysis highlighted distinct impairment clusters in attention and executive functioning. Longitudinal follow-up indicated partial recovery after rest, though executive deficits persisted. Qualitative findings supported these outcomes, as participants reported “cognitive fog,” difficulty sustaining focus, and emotional dysregulation under sleep loss. The integration of objective and subjective data underscores that sleep deprivation exerts broad, multi-domain impairments on cognition that extend beyond simple lapses of vigilance. These results emphasize the critical role of adequate sleep in maintaining academic, occupational, and public safety performance, and highlight the need for policies and interventions that safeguard sleep health.