1 Memory Systems and Models
Learn how memory encodes, stores, and retrieves information, and compare major memory models, long-term memory types, retrieval cues, and causes of forgetting.
How memory works
Memory is the set of processes that lets information be encoded, retained, and later retrieved. These processes interact: what is attended to and encoded influences what can be stored and which cues may later bring information to mind. Remembering is not simply replaying a perfect recording; can be incomplete and reconstructive.
The three memory processes
, , and
is the initial processing of information. Attention selects some sensory input, and the mind represents it in a form that can be used later. For example, learning a new name may involve noticing its sound and connecting it to a person’s face. Meaningful elaboration—relating new material to what is already known—can create useful associations.
is the persistence of information over time. Newly learned material may be stabilized through consolidation, but is not necessarily a literal, unchanging record.
is access to stored information. Recall requires producing information, such as answering a question without options. Recognition involves identifying previously encountered information, such as selecting the correct answer from choices. Recognition often provides more support than recall.
Models of memory
The multistore model
Atkinson and Shiffrin proposed three interacting stores: sensory memory, short-term memory, and long-term memory. Sensory memory briefly holds incoming sights, sounds, and other sensations. Attention selects some information for short-term processing; rehearsal and other control processes may help maintain it or encode it for long-term . Information can also be retrieved from long-term memory into current thought.
The multistore model is a useful framework, but its stages should not be treated as rigid boxes through which every memory must pass in exactly the same way.
describes a limited-capacity system that temporarily holds and manipulates information for an ongoing task. It is more than a passive short-term store: when following spoken directions, for example, a person must keep the steps in mind and use them to guide action.
Baddeley and Hitch’s influential model proposed a central executive that directs attention and coordinates specialized systems. The phonological loop handles speech and sound, while the visuospatial sketchpad handles visual and spatial information. A later development added an episodic buffer, which helps integrate information across these systems and long-term memory. Short-term is therefore one aspect of , not a perfect synonym for the whole system.
Types of long-term memory
Long-term memory can be organized by the kind of information remembered. These categories describe different kinds of remembering; they are not simply separate time stages in the multistore model.
Declarative memory
is information that can generally be consciously recalled and described. It includes:
Episodic memory: personally experienced events situated in time and place, such as remembering a particular birthday.
Semantic memory: facts, meanings, and general knowledge, such as knowing what a word means.
Nondeclarative memory
is expressed through performance or changed responses, without necessarily recalling the learning episode. Procedural memory supports learned skills and habits, such as riding a bicycle.
cues and forgetting
A memory may be stored yet difficult to access at a particular moment. cues work best when they overlap with information present during . A topic, place, or associated idea may prompt recall of a name that could not be produced without a hint. Thus, failure to recall does not always mean that information was never learned or has been completely lost.
Forgetting can reflect weak or incomplete , loss or weakening of a memory over time, or difficulty retrieving it. occurs when other learning competes with remembering. Earlier information can hinder new learning, which is proactive ; later learning can hinder access to earlier information, which is retroactive .
An apparent memory failure may therefore arise at different points in the , , and process.