Basis set of schemas

In many domains, a person may develop a basis set of schemas quite naturally. In a number of educational domains, however, we have evidence that students are not developing powerful schemas... 

The issue of how to identify an effective basis set of schemas for use in instruction is a thorny one for a number of reasons. At first glance, it might seem that one need only ask experts how they solve arithmetic problems and then extract or abstract their schemas from the responses. This approach has at least three limitations. The first limitation is endemic to all schema research People are not very good at telling us how and what they think. Almost every researcher who studies expertise faces this problem. As Nisbett and Wilson (1977) illustrated in their research, individuals... 

What I would really like to know are the schemas of old experts that they used when they were young experts. It would be incredibly valuable to know which young-expert schemas will eventually develop into old-expert ones. This knowledge could be ascertained only by a longitudinal study of some years duration, which has yet to be carried out. In its absence, we must use other means for selecting a basis set of schemas to guide instruction. 

The complete schema analysis described here yielded three main findings. First, situational knowledge is sufficient to characterize story problems. Only a small set of situations is required to make the distinctions. This is a key point, because it renders feasible the quest for a basis set of schemas. Second, although situational knowledge may seem so obvious to the experienced researcher and educator as to be almost blatant, in fact, almost no students or teachers appear to be using it in problem solving. Virtually none of the more than 100 individuals in the studies here showed any awareness of situational detail. Third, as one would hope, situational knowledge is relatively easy for students to acquire. Even the mathematically naive students were able to understand and learn about the situations. 

Chapter 5 shows how schema theory can be practically implemented. It gives a detailed description of one example of schema-based instruction, the Story Problem Solver (SPS). SPS is a computer-based system of instruction constructed around schema theory, using the basis set of schemas developed in chapter 3. It provides fundamental instruction enabling students to build schemas. A second computer program, the Problem Solving Environment (PSE), is also described in chapter 5. PSE provides an exploratory environment in which students can practice and utilize their schema knowledge about story problems. 

A point to be highlighted is that students will develop schemas about the subject matter whether instruction takes a schema-based approach or not. Learners will search for structure and relationships. Thus, the questions to be asked about schema-based instruction do not center on whether or not students create schemas. They do. The questions focus instead on the nature of the schemas that are developed. We ask whether the instruction itself can promote more cohesive and better structured schemas than would instruction having another foundation. It is here that the basis set of schemas becomes important, because these lay the groundwork for the instructional design. 

Finally, schema-based instruction differs from other instruction in that it targets explicitly the development of links that are central to the basis set of schemas. This aspect of instruction is frequently taken for granted. Schema-based instruction will stress repeatedly how and why different elements of the domain are related. 

The fundamental question, of course, is why should they Of what use is situational knowledge Its importance lies in the development of strong schemas for problem solving. Situational knowledge has the potential to serve as the anchor for the creation of a basis set of coherent, cohesive schemas that link all of a student s knowledge about story problems. Situational knowledge is the means by which semantic and syntactic information may be compiled in an individual s knowledge network about such problems. 

Database schemas are centrally stored and controlled. Data definitions (schema) are stored in the centralized data dictionary. The user s view(s) of the database is defined and stored in the same data dictionary. Programs are given access to individual data fields, records, sets and areas of the database on a need-to-know basis. The database administrator creates and maintains integrity of the database schemas. The benefits of this approach are ... 

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