The Working Memory Model

Working memory is not just a box where information sits. It's a working system, the mental space where you actively hold and manipulate information while using it, not just store it. The model splits that system into parts. The central executive is the boss: it directs attention, decides what matters, and assigns tasks to two helper systems. The phonological loop handles verbal and auditory information, looping sounds and words through an inner voice so you can rehearse them. The visuospatial sketchpad handles visual and spatial information, building and holding mental images and layouts.

Because these two helpers run on different material, they can work at the same time without tripping over each other. Rehearsing a phone number keeps the phonological loop busy with sound. Picturing your walk home keeps the sketchpad busy with images and layout. The central executive just has to keep both assignments running. But ask someone to hold two phone numbers at once, and both numbers need the same loop. They compete for one narrow channel, so one number degrades or gets overwritten by the other.

This is also why someone talking to you while you rehearse digits wrecks your count: incoming speech floods the same phonological loop, overwriting the rehearsal. The model sits right next to short-term memory in the unit because it replaces that older, simpler idea. Short-term memory was treated as one passive holding bin. Working memory reframes it as an active, multi-part workspace, setting up later topics on attention and encoding into long-term memory.