Short-term memory is the ability to hold a small amount of information in an active, readily accessible state for a short time. It is a simple "store": unlike working memory, it holds data but does not manipulate it.
Capacity and duration
Historically, the capacity of short-term memory was estimated at "seven plus or minus two" items (George Miller, 1956), but modern data have lowered that estimate to about 3–5 chunks. Without rehearsal, information is held for only about 15–30 seconds before it fades. Mentally repeating it refreshes the trace and prolongs storage. Capacity can be increased by grouping data into meaningful blocks — chunks.
The link with working and long-term memory
Short-term memory is only a temporary store. Working memory adds processing to it: comparing, rearranging and updating data. Some information from the short-term store, with the involvement of the hippocampus, is consolidated into long-term memory — a stable trace that can last for years.
Memory in aging and disease
A slight decline in memory is a natural part of aging and begins as early as young adulthood. However, a marked worsening of short-term and especially visual memory is characteristic of Alzheimer's disease and the mild cognitive impairment that precedes it, where the "binding" of an object's features suffers. A doctor can help tell the norm from pathology.
Calculate using this marker
Calculators where Short-term memory is used directly:
Frequently asked questions
How many items fit in short-term memory?
The classic estimate is “7±2”, but modern research gives about 3–5 chunks. Capacity grows if you group data into meaningful blocks (chunks) — for example, memorizing a phone number in parts.
Is forgetting names a disease?
In itself, no: a slight slowing of memory is normal in aging. What should raise concern is progressive worsening, loss of recent events and everyday difficulties — that is a reason to see a doctor.