Baddeley's Model of Working Memory
Baddeley's framework divides working memory into the phonological loop (verbal and acoustic information), the visuospatial sketchpad (visual and spatial data), the episodic buffer (integrating information across domains), and the central executive (attentional control). The subsystems are described as having partly separate capacity limits, which is one account of why verbal and spatial tasks can sometimes be performed together with little interference.
Capacity and Individual Differences
Working memory capacity varies between individuals, and it has been reported to correlate with fluid intelligence, reading comprehension, and academic performance. The classic estimate of 7 plus or minus 2 items proposed by Miller (1956) refers to short-term storage, while active manipulation leaves less capacity available for holding items. Training programs like dual n-back aim to expand this capacity, though transfer effects remain debated.
Working Memory in Daily Life
Many complex mental tasks rely on working memory - from following multi-step instructions to mental arithmetic and holding a conversation while navigating. Stress, sleep deprivation, and aging are associated with lower working memory performance. Strategies like chunking, rehearsal, and external memory aids help compensate for its inherent limitations.