memory- Multi store model (atkinson and shiffirin)

What is the Multi-Store Model of Memory (MSM)?

The MSM, proposed by Atkinson and Shiffrin, explains how memory is stored, transferred between different stores, retrieved, and forgotten.

What does the MSM consist off?

Consists of three stores: Sensory Register (SR), Short-Term Memory (STM), and Long-Term Memory (LTM).

Information flows in a unidirectional manner (SR → STM → LTM).

What is the Sensory Register?

The first memory store that receives sensory information from the environment.

One sub-store for each sense (e.g. echoic = auditory).

Very large capacity.

Very brief duration: < 0.5 seconds.

Only information we pay attention to passes to STM.

Features of Short-Term Memory (STM)

Encoding: Primarily acoustic (Baddeley).

Capacity: 7 ± 2 items (Miller).

Duration: 18-30 seconds (Peterson & Peterson).

Maintenance Rehearsal: Repeating info keeps it in STM.

Transfer to LTM: Prolonged rehearsal transfers info to LTM.

Forgetting: Occurs when rehearsal does not happen.

Features of Long-Term Memory (LTM)

Encoding: Primarily semantic.

Capacity: Potentially unlimited.

Duration: Can last a lifetime - over 46 years (Bahrick et al).

Retrieval: To remember something, it must be transferred back to STM for conscious recall.

Predictions of the MSM - Store Damage

STM Damage:

LTM is not affected.

Cannot form new LTM as transfer is impaired.

LTM Damage:

STM and Sensory Register unaffected.

Cannot store or retrieve old memories from LTM.

Case Study Support - Henry Molaison (HM)

Background: Had hippocampus removed to treat epilepsy.

Findings: Intact STM.

Damaged LTM: could not form new long-term memories.

Conclusion: Supports MSM - separate stores exist and can be independently damaged.

Support from Neuroimaging

Findings:

Frontal cortex active when recalling short-term memories.

Hippocampus active when recalling long-term memories.

Conclusion: Brain uses different areas for STM and LTM, supporting MSM's separate stores.

Strength of MSM - Qualitative Differences

Acknowledges different types of encoding, duration, and capacity for STM vs LTM.

STM: Acoustic encoding.

LTM: Semantic encoding.

Supporting Studies: Baddeley, Miller.

Conclusion: Provides an accurate and evidence-based account of memory stores.

Limitation - Types of LTM (Tulving et al.)

LTM isn't a unitary store. Includes:

Episodic (events)

Semantic (facts)

Procedural (skills)

Some LTM types are retrieved unconsciously (e.g. procedural), others consciously (e.g. semantic).

Conclusion: MSM oversimplifies LTM.

Limitation - Rehearsal Type (Craik & Watkins, 1973)

MSM says amount of rehearsal matters (maintenance).

Craik & Watkins argue type of rehearsal is key.

Elaborative rehearsal (linking new info to existing knowledge) is better for transfer to LTM.

Conclusion: MSM does not consider deeper processing.

Limitation - Case Study of KF

KF had impaired verbal STM but intact visual STM.

Could still form new long-term memories.Conclusion:

MSM oversimplifies STM as a single store.

Suggests multiple STM stores (e.g. verbal vs visual).

Limitation - Involuntary LTM Encoding

MSM says rehearsal is needed for transfer to LTM.

However, people often remember:

Smells

Songs

Experiences...without consciously rehearsing them.

Conclusion: Not all LTM formation relies on rehearsal, contradicting MSM.