The multi-store model of memory

1. Atkinson and Shiffrin (1968) argued that memory is not one box but three separate stores arranged in a line.
2. Information arrives in the sensory register, may pass into short-term memory, and may then pass into long-term memory.
3. The stores differ in three ways: what they take in, how much they can hold, and how long they hold it for.
4. Nothing moves along the line by itself, because each step depends on you doing something with the information.

The sensory register

1. The sensory register is the first store, and it receives everything your senses pick up.
2. It takes information in a modality-specific way, so iconic (visual), echoic (auditory) and haptic (touch) input stay separate.
3. It holds that raw input for only a fraction of a second before the trace decays.
4. Almost all of it is lost, because you can only attend to a tiny part of what arrives.

The capacity of short-term memory

1. Capacity means how much a store can hold at any one moment.
2. Short-term memory has a very limited capacity of roughly 5 to 9 items, which Miller (1956) wrote as 7 plus or minus 2.
3. Once it is full, new items push older ones out, so the store never grows to fit what you are given.

The duration of short-term memory

1. Duration means how long a store can keep information available.
2. Short-term memory has a short duration of about 15 to 30 seconds, and almost 90 per cent of information was lost when rehearsal was prevented for 18 seconds.

The capacity of long-term memory

1. Long-term memory has no known limit, so its capacity is described as potentially unlimited.
2. You are not thought to reach a point where a new memory can only be stored by deleting an old one.

The duration of long-term memory

1. Long-term memory has a potentially lifelong duration, so information can stay available for decades.
2. Bartlett's participants still produced recognisable versions of a story almost ten years after reading it, which shows how long a trace can last.

The role of attention

1. Attention is what moves information from the sensory register into short-term memory.
2. Whatever you attend to is passed on, and everything you do not attend to simply decays where it is.

The role of rehearsal

1. Rehearsal is repeating information or actively thinking it over while it sits in short-term memory.
2. Rehearsing keeps information circulating in short-term memory, which holds it there beyond its usual short duration.
3. Enough rehearsal transfers the information into long-term memory, and in this model rehearsal is the route by which that happens.

Strengths of the model

1. Peterson and Peterson (1959) support the claim that short-term memory has its own short duration, because recall collapsed from about 80 per cent to about 10 per cent once rehearsal was blocked.
2. Amnesia gives further support for separate stores, since retrograde and anterograde amnesia damage different parts of memory.

Weaknesses of the model

1. The model is oversimplified, because it treats short-term memory and long-term memory as single unitary stores.
2. The support from Peterson and Peterson is narrow, because their 24 participants were all Indiana University students taking part as a course requirement.

Turning this into marks

1. Give the capacity and the duration of each store as figures rather than calling short-term memory small.
2. In a scenario, say what the person attended to and what they rehearsed.
3. The mark most often lost is listing a strength and a weakness without setting one against the other and reaching a judgement.