Short-term memory: overview, characteristics, and significance

Characteristics and components

Short-term memory is limited by both duration and capacity. Information typically decays within seconds unless actively rehearsed. Capacity is often described in terms of items or chunks — a commonly cited rule is "seven plus or minus two," though chunking and strategy can change how much can be handled. Short-term memory overlaps with the concept of working memory, which emphasizes manipulation as well as storage.

Working memory model

Modern accounts view short-term storage as part of a multi-component working memory system. Key components include:

• Phonological loop: holds verbal and auditory information.
• Visuospatial sketchpad: stores images and spatial layouts.
• Central executive: directs attention and coordinates subsystems.

These components help explain differences in how numbers, words, and visual patterns are temporarily retained.

How it differs from long-term memory

Short-term memory is temporary and fragile; long-term memory refers to information consolidated for prolonged retention. Transfer to long-term stores usually requires encoding processes such as rehearsal, meaningful association, or repeated exposure. Interference and lack of rehearsal prevent many short-lived items from becoming long-term memories.

Importance, testing, and clinical relevance

Short-term memory supports reasoning, comprehension, and learning. Psychologists assess it with tasks like digit span and n-back tests. Impairments can occur with aging, attention disorders, head injury, or neurodegenerative disease; clinical evaluation helps distinguish temporary lapses from pathological memory loss. For further reading on mechanisms and applied tests see short-term memory resources.