Modal Model of Memory
The Atkinson-Shiffrin three-store model of memory: sensory, short-term, long-term.
Why three stores instead of one?
Behavioural data (like the Serial Position Effect) and amnesia cases pointed to functionally separate stores rather than one undifferentiated memory.
Sensory Memory → Short-term Memory → Long-term Memory
- Sensory: huge capacity, fades in under a second
- Short-term: ~7 ± 2 items, seconds
- Long-term: effectively unbounded in capacity and duration
Working Memory later replaced the simple “short-term store” for most cognitive work, since it does more than just hold.