Baddeley's Working Memory Model
Your brain doesn't just have one simple short-term memory - it's actually a sophisticated system with multiple components working together. Baddeley and Hitch discovered this by testing whether people could do two tasks simultaneously, finding that visual and auditory tasks don't interfere with each other as much as two visual tasks would.
The model consists of four main parts: a central executive that acts like a boss, and three "slave systems" that handle different types of information. This explains why you can listen to instrumental music while reading (different systems), but find it harder to read while someone's talking to you (same system).
Acoustic vs semantic encoding research showed that short-term memory mainly uses sound-based coding (acoustic), while long-term memory focuses on meaning (semantic). Words that sound similar (like cat, cap, can) are harder to remember in the short term, but words with similar meanings cause more confusion in long-term memory.
Key Point: The Working Memory Model focuses specifically on the active, conscious memory you use when working on complex tasks - not just passive storage.