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Cognitive load theory assumes that information should be structured to eliminate any avoidable load on working memory in order to enhance learning. We hypothesized that the appropriate type of structure may depend on the learner's level of expertise. Less expert learners using a diagram might require the diagram to be physically integrated with related text-based information in order to reduce cognitive load. However, the same diagram might be intelligible in isolation by more experienced learners, who might require the elimination of redundant text to reduce cognitive load. The results of three experiments indicated that as level of expertise increased, the best instructional designs changed from ones in which diagrams and text were physically integrated to ones in which the text was eliminated.
INTRODUCTION
When scientific or technical information is presented to learners, it usually is conveyed via multiple sources. Frequently, instruction involves a combination of textual and diagrammatic information. How the text and diagrams are designed and related can have substantial effects on the material's learnability, and the ideal instructional design may interact with the learner's level of expertise. This paper investigates relations between instructional design and levels of expertise. We begin with a discussion of aspects of cognitive architecture that are relevant to instructional design. Processing of information occurs within a limited working memory (Baddeley, 1992; Miller, 1956). Only a few items or elements of information can be handled in working memory at one time. From the perspective of instructional design, it is this restriction that provides the major limitation of working memory. Too many elements can overwhelm working memory, decreasing the effectiveness of instruction.
In contrast to working memory, long-term memory can hold an unlimited number of elements in the form of hierarchically organized schemas (Chi, Glaser, & Rees, 1982; Larkin, McDermott, Simon, & Simon, 1980). Schema is defined as a cognitive construct that permits people to treat multiple subelements of information as a single element, categorized according to the manner in which it will be used. For example, everyone has acquired schemas for lines and angles and, through further learning, has acquired higher-order schemas that combine these lines and angles into geometric shapes such as squares. The schema for a square is stored in long-term memory and, despite consisting of multiple...