ABSTRACT
Consider what happens when a person learns a complex subject matter. By complex, we mean something that takes a considerable amount of time to learn—time measured in weeks and months, not in hours or days. Complex topics contain a large structure of information composed of the relevant concepts and processes that make up the topic. A large amount of time is necessary just to incorporate such a mass of material into a person’s memory structure. Moreover, sheer rote acquisition of the concepts is not enough. The material must be structured in such a way that relevant concepts can be related properly to one another. The procedures must be learned well enough that they can be performed when needed, and more important, so that they can be performed when the situation is not quite the same as when the concept was learned.
