Psychology › Thinking, memory & biases
Memory and how it works
Studied since 1885· Concept
Well replicatedStrong, repeated evidence.
Memory is how the brain encodes, stores and retrieves experience; it rebuilds the past each time rather than replaying a recording.
See it on the Psychology map →What it says
In 1885 Hermann Ebbinghaus memorized lists of nonsense syllables and charted the 'forgetting curve': most forgetting happens within the first day, then it slows sharply. Memory works in three stages: encoding (taking information in), storage and retrieval. It is not one system but several (see memory systems). The hippocampus helps form new long-term memories, and sleep helps stabilize them. Each recall partly rebuilds a memory, which is why confident memories can still be wrong.
Why it matters
Memory underlies learning, skill, identity and testimony. Knowing it is reconstructive changed courtroom practice and how good teachers and trainers teach.
Think of it like
Less like pulling a file from a cabinet, more like a contractor rebuilding a room from notes: the layout holds, details drift.
The evidence
Well replicated. Ebbinghaus's forgetting curve was successfully repeated in 2015 by Jaap Murre and Joeri Dros. Lab experiments, amnesia patients such as H.M., and brain imaging support the core picture.
Open questions
Exactly how a specific memory is physically stored, the 'engram', is only partly known; since 2012, studies in mice have begun tagging and reactivating such cells.
Inside this (4)
Connections (4)
▸Working memory is the short-term workspace of Memory and how it worksWell replicated
The connection
Working memory is memory's active front end: information is held and processed there before it is stored long-term, and long-term memories are pulled back into it when needed. Working with ideas for meaning there, rather than just repeating them, makes them more likely to last.
Who showed it and when
Built on Atkinson and Shiffrin's short-term store (1968) and Baddeley and Hitch's 1974 model, in the US and Britain.
The evidence
Lab studies show items processed for meaning are remembered far better later (Fergus Craik and Robert Lockhart's 'levels of processing', 1972).
Open questions
Some models, such as Nelson Cowan's, treat working memory as simply the currently activated part of long-term memory, not a separate store.
▸False memories and the misinformation effect (Loftus) show the reconstructive nature of Memory and how it worksWell replicated
The connection
If memory were a recording, a later question could not change it. Loftus showed that wording, suggestion and information received afterward do change what people recall, supporting Frederic Bartlett's 1932 view that remembering is reconstruction from fragments plus expectations.
Who showed it and when
Bartlett at Cambridge, 1932; Loftus at the University of Washington from the 1970s, later at the University of California, Irvine.
The evidence
Hundreds of misinformation experiments, plus brain imaging showing true and false memories activate overlapping regions.
Open questions
Whether misinformation overwrites the original memory or both versions survive and compete is still debated.
▸Spacing and retrieval practice exploit the mechanics of Memory and how it worksWell replicated
The connection
Spacing and testing work with memory's known quirks. Some forgetting between sessions makes the next retrieval harder, and effortful retrieval strengthens a memory more, what Robert Bjork called 'desirable difficulties'. Each successful recall also makes the memory easier to find next time.
Who showed it and when
Ebbinghaus in Berlin, 1885; Robert and Elizabeth Bjork at UCLA from the 1990s; Henry Roediger at Washington University in St. Louis.
The evidence
Controlled experiments show testing beats restudying even without feedback, with benefits that grow as the delay before the final test lengthens.
Open questions
The exact mechanism is debated: retrieval may add new routes to a memory, strengthen existing ones, or update the context it is linked to.
▸Dementia and Alzheimer's disease erode Memory and how it worksWell replicated
The connection
Dementia usually strikes memory first, in a typical order: recent events and new information go before old memories, which can stay vivid for years. Learned skills and habits, stored in other brain systems, often last longest, which is why someone may still play piano after forgetting the day's visit. Later, language, judgment and recognizing people decline.
Who showed it and when
Observed since Alzheimer's 1906 case of Auguste Deter, who said 'I have lost myself'; mapped in detail by memory clinics and research centers worldwide since the 1980s.
The evidence
Standard memory tests track the decline year by year, and brain scans tie it to damage in the hippocampus and later the wider cortex.
Open questions
Why musical and emotional memories often survive so long, and why some dementias, such as frontotemporal, spare memory early and change personality first.