Working memory
Also known as: short-term working memory
In one sentenceWorking memory holds information in mind for seconds while you manipulate it, supporting mental arithmetic, conversation and planning.
How it differs from short-term memory
Short-term memory is about briefly storing information; working memory also covers using it. Holding an intermediate result while you finish computing 37 × 4 in your head is working memory at work.
The Baddeley–Hitch model
In 1974 Alan Baddeley and Graham Hitch proposed splitting working memory into subsystems.
| Component | Role |
|---|---|
| Central executive | Allocates attention and coordinates the subsystems |
| Phonological loop | Briefly holds speech-based information, as when you rehearse a phone number |
| Visuospatial sketchpad | Handles visual and spatial information such as location and shape |
| Episodic buffer (added 2000) | Binds information into coherent episodes and links it to long-term memory |
Capacity limits
In 1956 George Miller summarized observations that people can hold about seven items at once. Nelson Cowan later argued that when rehearsal and grouping are prevented, true capacity is closer to four chunks.
Chunks matter: ten separate digits become three chunks when grouped like a phone number (415-555-0132). Grouping information meaningfully, called chunking, lets the same capacity carry more.
In the brain
Monkey studies found that prefrontal neurons keep firing after a stimulus disappears. This “delay-period activity” has long been studied as a cellular basis of working memory (Goldman-Rakic, 1995), making working memory a prime example of a cognitive function studied through sustained activity in neural circuits.
Related entries
- Neural circuit — A neural circuit is a group of neurons connected by synapses that work together to carry out a specific function such as sensory processing, movement or memory.
References
- Working memory. Baddeley AD, Hitch G. Psychology of Learning and Motivation 8, 47–89 (1974)
- The episodic buffer: a new component of working memory?. Baddeley A. Trends in Cognitive Sciences 4, 417–423 (2000)
- The magical number seven, plus or minus two: some limits on our capacity for processing information. Miller GA. Psychological Review 63, 81–97 (1956)
- The magical number 4 in short-term memory: a reconsideration of mental storage capacity. Cowan N. Behavioral and Brain Sciences 24, 87–114 (2001)
- Cellular basis of working memory. Goldman-Rakic PS. Neuron 14, 477–485 (1995)