# memory (cognitive)

the ability of a person to keep information about previous events and retrieve it later

- Computed level: L20 (depth in the emergence graph, not abstraction)
- Status: review  ·  Domain: common  ·  Arena: everyday

## Emergence
**Emerges from:** [ability](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-ability.capacity), [information](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-information.knowledge), [event](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-event.occurrence), [find](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-find.search), [keep](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-keep.maintenance), [people](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-people.social), [previous](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-previous.temporal), [time](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-time.dimension), [later](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-later.temporal)

**Through:** The capacity to persist knowledge of past events enables retrieval when sought by a person.

**Novel properties:**
- temporal persistence of knowledge
- recall on demand
- integration of retention and access

## Examples
- The Voyager 1 probe retains navigation data in radiation-hardened memory since 1977, still functioning at over 24 billion kilometers from Earth. *(engineering)*
- The hippocampus in London taxi drivers shows enlarged gray matter after memorizing complex city routes for the Knowledge exam. *(biology)*
- The Internet Archive saves snapshots of web pages, like the first Google homepage from 1998, retrievable decades later. *(computing)*

## Used by
- [remember](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-remember.cognitive) (L21)

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*Canonical: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-memory.cognitive*  
*Structured data: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-memory.cognitive.json*  
*Every definition provably resolves to space, time, energy and pattern.*