Working Memory Capacity
topic
Working memory — the limited-capacity, actively maintained mental workspace that holds and manipulates information during cognitive tasks — is measurably reduced in capacity and efficiency by sleep deprivation, with the ability to hold and process multiple items simultaneously degraded proportionally with sleep restriction. This reduction in working memory underlies many of the downstream cognitive impairments of sleep deprivation: reduced reading comprehension, impaired arithmetic, degraded decision quality, and reduced complex reasoning.
Role
Working memory is the cognitive bottleneck through which all complex thinking passes — and its reduction by sleep deprivation impairs every cognitive task that requires holding multiple pieces of information in mind simultaneously, which is to say virtually every task of consequence in knowledge work. The professional who attempts complex analysis, strategic planning, or creative production from a sleep-deprived state is doing so with a reduced number of mental juggling balls available — producing outputs that feel normal but are measurably less comprehensive, less accurate, and less creative than the same person's well-rested outputs.