West et al. (1991) propose that knowledge with different properties is processed and organized differently in cognitive structure. They support three broad categories or types of knowledge:
- Procedural, and
- Conditional (West et al.).
Declarative knowledge is described by West et al. (1991) as factual in nature. It is stored in the form of propositions and networks of propositions. Propositional networks are subdivided into two types:
- Semantic and
Semantic networks represent lists of elements that may or may not have strong relationships among each other, but whose access and recall is aided by their relative position in the network. They also support Anderson’s (1985) notions on episodic networks by suggesting that they represent connected chains of proposition whose relationships with each other are usually in the form of historical narrative. Procedural knowledge consists of order-specific, time-dependent, sequential instructions that characterize knowing how to accomplish some task (West et al.). The distinction between procedural knowledge and episodic network declarative knowledge is the focus on the process independent of content in the former and the focus on the relationships among a sequence of specific facts in the latter (West et al.).
Prawat (1989) suggests that conditional knowledge represents a higher order cognitive process in that it is concerned with the description of specific criterion combinations and contexts that may be matched to a range of responses to them. West et al. (1991) draw on this to conclude that conditional knowledge defines the knowing when and why to use a procedure.
Once taxonomy of knowledge is described, the organization of knowledge in cognitive structure becomes a concern for the learning theorist (West et al., 1991). West et al. propose that the value in well-structured knowledge lies in its logical order, its usefulness in making predictions about the future, and its value for making inferences when there are gaps in its structure.