Working memory is the cognitive system that holds information actively in mind while you use it. It is not the same as short-term memory. It is more dynamic, involving both storage and manipulation of information. Alan Baddeley and Graham Hitch proposed their influential model of working memory in 1974, identifying a central executive that coordinates attention, a phonological loop that holds verbal and acoustic information, a visuospatial sketchpad that holds visual and spatial information, and (added later) an episodic buffer that integrates information across systems. Understanding these components matters for designers because different interface contexts load different working memory subsystems.