Learning mechanisms: schema acquisition

A schema is a cognitive construct that organizes the elements of information according to the manner with which they will be dealt. An early discussion of schemas was presented by Bartlett (1932). He demonstrated that what is remembered is only partly dependent on the information itself. Newly presented information is altered so that it is congruent with knowledge of the subject matter. Knowledge of subject matter is organized into schemas and it is these schemas that determine how new information is dealt with. For example, consider schemas that deal with common objects such as trees. No two trees have identical elements but each tree seen can be instantly incorporated into a tree schema. As a consequence, if asked to describe a particular tree from memory, a person’s description will be heavily influenced by a tree schema rather than entirely by the particular tree elements (leaves, branches, colour etc.) actually seen. Tree schemas allow people to deal effortlessly with the potentially infinite variety of objects called trees.

In a similar manner, there are schemas for dealing with problems. These schemas allow the classification of problems into categories according to how they will be dealt with, i.e., according to solution mode (e.g., see Chi, Glaser & Rees, 1982). Most people who have completed algebra courses, if faced with an algebraic problem such as (a + b)/c = d, solve for a, will be able to solve it immediately irrespective of the actual pro-numerals used. If, for example, the expression on the right side of the equation is long and complex, a schema will indicate that complexity at this location is irrelevant and the problem will be no more difficult to solve than with a simple expression. Schemas for this category of algebra problems allow the infinite variety of expressions incorporated in the category to be dealt with.

Schemas can be used to explain most of the learned, intellectual skills that people exhibit. People are able to read the infinite variety of the printed and handwritten versions of text that they can potentially encounter because they have acquired schemas for each letter, many words and probably even many word combinations. Learning to solve problems occurs by learning problem categories defined by the moves required for solution. These schemas permit people to readily solve problems that otherwise they would have immense difficulty solving if they had to rely solely on constructing a solution based on first principles.

Interest in schema theory has waxed and waned over many years with alternative terminology frequently being employed. Miller’s (1956) concept of a chunk could be used as readily as the term schema, as could Schank and Abelson’s (1977) scripts. In more recent times, Koedinger and Anderson (1990) provided an excellent formal analysis of schema-based problem solving. While their model is restricted to geometry problem solving, there seems little reason to suppose that the basic principles they employ should not be genera&able to a wide range of problem solving materials. Low and Over (1990) provide techniques for assessing schema acquisition for word problems that may be generalize to other types of material. In summary, knowledge and intellectual skill based on knowledge is heavily dependent on schema acquisition. Schemas provide the basic unit of knowledge and through their operation can explain a substantial proportion of our learning-mediated intellectual performance.