THE CONTROL PROCESSES OF SHORT-TERM MEMORY
by
R. C. Atkinson and R. M. Shiffrin
TECHNICAL REPORT 173
April 19, 1971
PSYCHOLOGY SERIES
Reproduction in Whole or in Part is Permitted for
any Purpose of the United States Government
This research has been supported by the National Science
Foundation under grant NSFGJ-443X.
INSTITUTE FOR MATHEMATICAL STUDIES IN THE SOCIAL SCIENCES
STANFORD UNIVERSITY
STANFORD, CALIFORNIA
THE CONTROL PROCESSES OF SHORT-TERM MEMORY
R. C. Atkinson and R. M. Shiffrin
Stahford University
Stanford, California 94305
Human memory is divided into a short-term working memory and a long-term permanent memory. Control processes act within the short-term working memory to make decisions and regulate information flow, thereby controlling learning and forgetting.
The system by which information is stored in and retrieved from memory has always been a topic of great interest to psychologists. The English associationists and early experimental psychologists like Wilhelm Wundt, William James, and Ernst Meumann relied upon introspective techniques to generate their theories. Their introspections led them before the turn of the century to divide memory into short-term and long-term components. They discerned a clear difference between thoughts currently present in consciousness and those that could be brought to consciousness after a search of memory that often required considerable effort. For example, this sentence is in your current awareness, but the winner of the 1968 World Series, while probably in memory, requires some effort to retrieve and in fact may not be found at all.
Despite its intuitive attractiveness, the short- versus long-term view of memory was largely discarded when psychology turned to behaviorism which emphasized animal as opposed to human research. The short- versus long-term distinction received little further consideration until the 1950's when a number of psychologists, particularly Donald Broadbent in England, Donald Hebb in Canada, and George Miller in the United States,
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reintroduced it (see George A. Miller, Information and Memory, Scientific American, 1956, 195 (2), 42-47). The growth of two-process systems was accelerated by the concurrent development of computer models of behavior and mathematical psychology. The two-process viewpoint is now undergoing considerable theoretical development and is the Subject of a large research effort. In particular, the short-term memory system, which we will callshort term store(or STS) , has achieved a position of pivotal importance. Its importance stems from processes carried out in STS that are under the immediate control of the Subject. Thesecontrol processesgovern the flow of information in the memory system; they can be called into play at the Subject's discretion, with enormous consequences on performance.
Some control processes are used in many situations by everyone, and others are used only in special circumstances.Rehearsal, an overt or covert repetition of information, is employed in numerous situations: when remembering a phone number until it can be written down, when remember; i.ng the names of a group of people to whom you have just been introduced, and when copying a passage from a book, to name a few examples.Codingrefers to a class of control processes in which long-term retrieval is enhanced by placing the to-be-remembered information in a context of additional and easily retrievable information. For example, students sometimes learn the twelve cranial nerves with the use of the mnemonic "OnOldOlympus'TinyTopAFinnAndGermanViewedSomeHops" where the first letter of each word corresponds to the first letter of each nerve.Imagingrefers to a control process in which verbal information is remembered through the use of visual images. The ancient Greeks made
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extensive use of this process. Cicero suggested learning long lists (or speeches) by placing each member of the list in a visual representation of successive rooms of a well-Known mansion. A number of other controlprocesses, including decision rules, organizational schemes, retrieval strategies and problem solving techniques, will be encountered in this article. The point to Keep in mind is the optional nature of control processes. In contrast to permanent structural components of the memory system, the control processes are selected at the Subject's discretion; they may vary, not only with different tasks but even from one encounter with the same task to the next.
An Outline of the Memory System
We believe that the overall memory system is best described in terms of the flow of information into and out of STS and the Subject's control of this flow. Before describing the system it is helpful to introduce terminology with which to discuss information flow. All phases of memory are assumed to consist of small units of information which are associatively related. Any set of information units that are closely interrelated will be termed an "image" or "trace" (thus "image" does not necessarily imply a visual representation). If the pair "TKM - 4" is presented for memory, the image stored might include the size of the card on which the pair is printed, the type of print, the sound of the various symbols, the semantic codes, and numerous other units of information.
The basic phases of the memory system and the types of information flow are illustrated in Figure 1. Information from the environment is accepted and processed by the sensory registers in the various sensory
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Figure Caption
Figure 1. Information flow in the memory system. Environmental information is processed by sensory registers in the various physical modalities and entered into short-term store (STS). The information remains temporarily in STS, the length of stay depending on control processes. While information remains in STS it may be copied into long-term store (LTS). While information remains in STS, information in LTS associated with it may also be activated and entered in STS. Thus, if a picture of a triangle is presented, this visual information is processed and entered into STS. Then, since the verbal name "triangle" is associated with this visual information in LTS, this verbal label is also entered into STS.