- Multi-store model
- Atkinson and Shiffrin's (1968) framework proposing three distinct memory stores: (1) the sensory register (holds raw sensory data for ~0.5–2 seconds); (2) the short-term store (limited capacity, ~7±2 items, duration ~15–30 s without rehearsal); and (3) the long-term store (potentially unlimited capacity and duration). Transfer from short- to long-term store is controlled by rehearsal. The model stimulated a generation of memory research and the first cognitive accounts of amnesia.
- Working memory
- Baddeley and Hitch's (1974) model replaced the unitary short-term store with a multi-component system: a central executive (attentional control and coordination); the phonological loop (maintaining verbal and acoustic information through subvocal rehearsal); the visuospatial sketchpad (maintaining visual and spatial information); and (added in 2000) the episodic buffer (a limited-capacity, multimodal buffer that integrates information from the other components and from long-term memory into a coherent, temporary episode).
- Episodic vs semantic memory
- Endel Tulving's (1972) distinction within declarative long-term memory. Episodic memory stores personally experienced events in their specific temporal and spatial context — memories of "what happened, when, and where." It supports mental time travel: re-experiencing the past and imagining the future. Semantic memory stores general knowledge, concepts, facts, and language meaning independent of the circumstances in which they were acquired. The two systems are dissociable: some patients lose episodic memory while retaining semantic memory (and vice versa).
- Procedural memory
- A form of non-declarative (implicit) long-term memory for skills, habits, and learned routines — knowing "how to" rather than "that." Procedural memories are acquired gradually through practice, expressed automatically in skilled performance, and largely inaccessible to conscious recollection. They depend on the basal ganglia, cerebellum, and motor cortex rather than the hippocampus. Patients with hippocampal amnesia (e.g., H.M.) can acquire new procedural skills normally despite being unable to form new episodic memories.
- Consolidation
- The process by which newly encoded memories are stabilised over time. Synaptic consolidation (occurring within hours) involves protein synthesis at active synapses and the strengthening of synaptic connections. Systems consolidation (occurring over weeks to years) involves the gradual transfer of hippocampus-dependent memories to neocortical networks for permanent storage. Sleep plays a critical role in systems consolidation — particularly slow-wave sleep (for declarative memories) and REM sleep (for procedural and emotional memories).
- Hippocampus and memory
- The hippocampus (a seahorse-shaped structure in the medial temporal lobe, present in both hemispheres) is essential for forming new declarative memories. The case of H.M. (Henry Molaison), who developed severe anterograde amnesia after bilateral hippocampal removal in 1953, demonstrated this role most vividly. The hippocampus is thought to bind together the distributed cortical representations that make up an episodic memory, enabling later reinstatement of the whole episode from a partial cue.