How does a fleeting thought become a lasting memory?
A phone number lasts about twenty seconds in your head unless you keep repeating it. What decides which moments survive for years?
▶ Start the storyIn the classic picture of memory, a fleeting thought becomes a lasting memory by passing through stages, with attention and acting as the doors between them. That picture is a model, proposed in 1968 by Richard Atkinson and Richard Shiffrin. Their three-part, multi-store model has a where information first arrives, a short-term store, and a long-term store. They also included control processes that regulate how information is transferred from one store to the next.
The first stage is extremely brief. The holds a raw trace of what your senses just picked up, and items in , the visual kind, decay after only 0.5 to 1.0 seconds. Information moves on to short-term memory only when you give it attention. Otherwise it decays rapidly and is forgotten.
Step 1:
A raw trace; for vision it fades within about a second
Step 2: Attention
Only what you attend to moves on
Step 3: Short-term store
About 18–20 seconds, 5–9
Step 4: and deeper thinking
Repeating, and relating to what you know
Step 5: Long-term store
Nearly limitless in duration and capacity
The short-term store holds whatever you are attending to, but not for long. Without active , such as repeating a number to yourself, information lasts roughly 18 to 20 seconds, and the store holds only 5 to 9 . A chunk can be bigger than it looks. The twelve digits 149283141066 are far too many to hold one by one, but they can be grouped into four chunks: Columbus (1492), ate (8), pie (3.14) and the Battle of Hastings (1066).
The long-term store is where memories can stay. In this model it is assumed to be nearly limitless in duration and capacity. Even a memory you cannot find may still be intact but unreachable, because the connections, cues or associations leading to it have deteriorated. Evidence that the two stores are separate came from patients with damage to the hippocampal region, who had nearly no ability to form new long-term memories even though their short-term memory remained intact.
Later research refined the model rather than simply confirming it. Baddeley and Hitch proposed that the short-term store is divided into several components, and critics found very little evidence that alone moves information into long-term memory: how deeply you think about meaning predicts long-term recall better.
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Recap
Attention carries information from the senses into short-term memory, and deeper thinking about meaning helps it reach long-term memory.
💡 A trick to remember it · Picture a leaky sieve, a small whiteboard and a huge attic, with your attention as the person carrying things from one to the next.
Surprising fact · Twelve digits are too many for short-term memory, but grouped into four meaningful chunks they fit.
Sources (1)
No source, no claim. Every fact in this lesson (19 claims) cites at least one of these.