Memory Models: Declarative, Procedural & Multi-Store

• Memory involves the encoding, storage, and retrieval of information.
• Cognitive psychologists use models of memory to conceptualize the memory system's architecture and processes.
• A memory model is a hypothesized representation of memory, outlining different stores and processes.
• Memory models evolve as new evidence emerges.
• Research distinguishes between different types of memory, potentially stored in different brain areas.

Types of Memory

• Declarative memory ("knowing what") involves conscious recall of facts and events.
• Episodic memory is a subset of declarative memory containing memories of specific events at a time and place.
• Semantic memory is a subset of declarative memory containing general knowledge of facts and people, not linked to time or place.
• Procedural memory ("knowing how") is the unconscious memory of skills and how to do things.

Multi-Store Model

• Atkinson and Shiffrin (1968) proposed the Multi-store Model (MSM) of memory.
• The MSM suggests a basic structure of memory and views humans as information processors.
• The MSM was inspired by computer science and assumes memory consists of separate storage locations with sequential processes operating uniformly.
• Short-term memory (STM) acts as a gateway to long-term memory (LTM).
• Memory stores operate with LTM through attention, coding, and rehearsal.
• Attention is needed to remember something.
• Rehearsal is essential to keep material active in STM until it can be stored in LTM.
• Sensory information enters sensory memory, which is modality-specific (related to senses).
• Visual (iconic) and auditory (echoic) stores are most important in sensory memory.
• Information stays in the sensory store for a few seconds, with a small amount moving to STM.
• STM capacity is about seven items (7+/-2), and duration is 6–18 seconds.
• Information in STM is lost if not rehearsed or may be displaced by new information.
• Rehearsal in STM determines what is stored in LTM.

Miller's Magic Number 7 (1956)

• The MSM argues that STM has limited capacity and duration.
• Miller (1956) proposed the "Magic Number 7" (plus or minus two) based on recall tests.
• The average memory span is between 5 and 9 items.
• Cowan (2010) argues that Miller's number may be overly optimistic.
• Cowan used a "running span procedure" where participants didn't know the list length in advance.
• Cowan found participants recalled 3-5 digits instead of 5-9.
• fMRIs show the parietal cortex plays a key role in STM (working memory).
• Brain activity in the parietal cortex correlates with STM capacity, leveling out after four digits (Vogel and Machizawa, 2004).
• Artificial lab procedures can have low ecological validity.

Long-Term Memory (LTM)

• LTM is conceptualized as a vast information storehouse with indefinite duration and unlimited capacity.
• Material in LTM is stored in outline form and may be distorted during retrieval. This aligns with schema theory.

Evidence Supporting the Model

• The case study of HM (Milner, 1966) provides biological evidence for separate STM and LTM stores.
• HM had anterograde amnesia, preventing new information transfer to LTM, but retained access to old memories.
• HM's ability to create new procedural memories suggests memory is more complex than the MSM predicts.

Galtzer and Cunitz Study

• Glanzer and Cunitz (1966) used free recall of 15-item lists with an interference task.
• Participants recalled words with no delay, 10-second delay, or 30-second delay.
• With no delay, the first five and last three words were recalled best.
• With a delay, recall of later items was poor, but recall of earlier items was maintained.
• Later words were held in short-term storage and were lost due to interference.
• Earlier words had been passed to long-term storage
• Primacy effect: the ability to recall words at the beginning of the list because they had already been transferred to long-term memory.
• Recency effect: the ability to recall words that have just been spoken because they are still in short-term memory.

Evaluation of the Multi-Store Model

• The multi-store model is now considered simplistic.
• It provides a good account of basic memory mechanisms (encoding, storage, retrieval).
• Several experiments support the assumption of multiple memory stores.
• Case studies of patients with brain damage, like HM, show impaired LTM but intact STM.
• Logie (1999) argues STM isn't just a gateway to LTM, but an interaction occurs.
• Information in STM is interpreted with previously stored knowledge and experience.
• STM is a 'workstation' handling information from the sensory store with knowledge from LTM. This aligns with schema theory.

Strengths of the MSM

• Significant research supports the theory of separate memory stores.
• The model is of historical importance.

Limitations of the MSM

• The model is over-simplified and assumes each store works independently.
• The model does not explain memory distortion.
• The model does not explain why some things may be learned with a minimal amount of rehearsal.
• There are instances where rehearsal does not lead to LTM transfer.