SOME PRINCIPLES OF MEMORY SCHEMATA
Original Publication Date: 1975-Dec-31
Included in the Prior Art Database: 2005-Sep-20
Software Patent Institute
DANIEL G. BOBROW: AUTHOR [+4]
A fundamental aspect of the structure of material contained within a large, intelligent memory system is that the contexts in which units of the stored information are accessed are critically important in determining how that information is interpreted and used. There are numerous proposals for the representation of information within memory. Most of the schemes currently under active consideration can be viewed as variants of list structures or semantic network structures. All these proposals have a number of common features, including context-i nde pendent linkage between units, and separation of processing and data elements. In this paper we propose a different form for the representation of information which embodies the opposite assumptions about linkage and the separation of data and process. We examine some implications of these memory structures with respect to how the con nections among different memory units are formed and interpreted, and we examine some of the issues of processing that arise when these memory structures are used. The form of our structures is an amalgamation of the principles from the literature on semantic networks, (for example, Norman, Rumelhart, & LNR, 1975; Quillian, 1969) the literature on actors (Hewitt, Bishop, & Steiger, 1974; Kay, 1974) and the new ideas on "frames" (Minsky, 1975; Winograd, 1975). We call our structures schemata to emphasize that they differ somewhat from any existing proposals. The word "schema" is ta,'L'-.en from the psychological literature, where it has had a long history, most commonly associated with the work on memory by Bartlett (1932), and by Piaget. We propose that one schema refers to another only through use of a description which is dependent on the context of the original reference. We also propose that these schemata are active processing elements which can be activated from Higher level purposes and expectations, or from input data which must be accounted for. II. MEMORY ACCESS USING DESCRIPTIONS An important property of human memory is the propensity to find analogical or metaphorical references. One event tends to suggest other events. Sometimes the relationships among the two events are, at best, metaphorical. Sometimes, only some limited aspect of the one event is related to the other. The nature of memory retrieval in humans is, of course, not well understood. We have no hard evidence on the paths followed in the effort to retrieve a particular piece of information or of the sorts of events that one is remided of while experiencing or remembering another. Despite the lack of firm evidence, we think it important to study memory structures that provide these flexible referential properties. Our goal is to specify a memory structure that allows one schema retrieved from memory to sugges others that should also be retrieved, and that is so constituted that it yields analogical and metaphorical retrieval as a fundamental mode of its operation. In this paper we speculate on the nature of memory reference processes that can lead automatically, without particular effort, to the richness of the retrievals that we believe to be a fundamental property of human memory. We suggest that memory units refer to one another through the use of descriptions. One memory schema refers to another by describing the other, perhaps by means of a short list of properties of the other. There are different levels of descriptions possible. At the one extreme, a description can be so complete that it unambiguously specifies a unique memory referent. At the other extreme, a description may be so vague that it fits almost every memory referent. We suggest that descriptions are normally formed to be unambiguous within the context in which they were first used. That is, a description defines a memory schema relative to a context. In novel contexts, a description yields novel results. We call such descriptions context -dependent descriptions.
THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.
SOME PRINCIPLES OF MEMORY SCHEMATA
By DANIEL G. BOBROW AND DONALD A. NORMAN*
CSL 75-4 JULY 1975
This paper deals with two related issues about memory: access and processing. Consideration of the properties of human memory lead us to suggest that memory is organized into structural units: schemata. We suggest that memory schemata refer to one another by means of context dependent descriptions that specify the referent unambiguously only with respect to a particular context. We argue that this method of memory reference has a number of desirable features for any intelligent memory system. For one, it leads automatically to metaphorical and analogical match of memory structures. For another, it produces systems that are robust and relatively insensitive to errors.
Consideration of systems which have limits on processing resources leads to some basic principles of processing that apply to memory structures. The quality of output of some processes is limited by the quality of data available to them (these are data-limited processes). The quality of the output of other processes is limited by the amount of processing resources available to them (these are resource- limited processes). All processes are either data-limited or resource-limited. We suggest that the overall system is driven from two levels--by the data, and by concepts or hypotheses of what is expected. These considerations of processing principles provide some useful interpretations of psychological phenomena, and suggest possible useful computational models for artificial systems.
Key Words and Phrases:
memory, access, schemata, human processing models, context-dependent descriptions, data- limited processes, resource-limited processes
*Donald A. Norman is in the Department of Psychology, University of California, San Diego.
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A fundamental aspect of the structure of material contained within a large, intelligent memory system is that the contexts in which units of the stored information are accessed are critically important in determining how that information is interpreted and used. There are numerous proposals for the representation of information within memory. Most of the schemes currently under active consideration can be viewed as variants of list structures or semantic network structures. All these proposals have a number of common features, including context-i nde
Xerpx Palo Alto Research Center Page 1 Dec 31, 1975
SOME PRINCIPLES OF MEMORY SCHEMATA
pendent linkage between units, and separation of processing and data elements. In this paper we propose a different form for the representation of information which embodies the opposite assumptions about linkage and the separation of data and process. We examine some implications of these memory structures with respect...