Conclusions
	The intended outcome of this paper was to establish some form of theoretical base for the production of computer based instruction materials. While the whole issue of instructional design was found to be somewhat clouded with numerous debates raging over major issues such as the instructional paradigm to be adopted and the effectiveness of user control, it has been possible to establish a number of criteria which appear to be valid. In this paper, a theory of storing knowledge as mental models was developed so as to form a basis for evaluating the various ideas, concepts and theories encountered in the literature. In my opinion, this theory has stood up well and would appear to be close to the semantic network or schema theory as described by Jonassen (1988). To develop such a mental structure, it would appear that a constructivist instructional approach must be taken as behaviourism would lead to a knowledge base which is somewhat fragmented rather than a well structured model. However, a behaviourist approach cannot be totally disregarded. As Jonassen (1991) argues, by its very nature, training often demands that a behaviourist approach be taken. Also, Spiro et al. (1990, 1991) state that different instructional strategies are required for novice and advanced learners and it could be suggested that a behaviourist approach could be well suited to the acquisition of basic skills. Figure 1 attempts to indicate where a particular type of educational software may be appropriate in the instructional process. The concept of storing knowledge as a mental model is to allow it to be manipulated in the problem solving process. If knowledge is not structured in this way, and so cannot be used in problem solving, it is said to be inert (Bransford et al. 1990). To prevent the formation of such inert knowledge, information should be taught in context and must be seen to have some relevance by the learner. One way of accomplishing this is by taking a case-based approach (Jonassen 1991). Hypertext, hypermedia and multimedia would appear to be the ideal tools for delivering information in a constructivist learning environment, however, hypermedia and multimedia would be superior to hypertext as they are capable of delivering material which is more 'information rich' than the text used in hypertext. However, there are a number of major problems which have to be overcome before these media can be used effectively. One of the major issues is that of navigation with researchers reporting cases of users becoming lost in 'hyperspace'. There are probably two main ways of overcoming this. The first is to develop better navigational tools so that users always know where they are and are given an indication of where a particular link will take them. The second is to introduce users to the hypertext/hypermedia concept gradually. Many people are still apprehensive about using computers and to let them loose on a large body of relatively unstructured information is a sure recipe for disaster. Users should be introduced to smaller, more structured systems so that they can become familiar with the process of navigating through materials before they progress to larger, unstructured systems. Another issue that must be resolved is that of user control. While the power of hypertext and hypermedia instructional systems would appear to lie in users being given complete control of the use of the system, current research would indicate that this is ineffective, however, this issue has to be re-considered from a hypertext/hypermedia perspective. It was disappointing to find little or no information about the effective use of graphics, animation, video and sound in computer based instruction materials. As these are an essential component of hypermedia and multimedia, it is important that a considerable amount of research is conducted in this area. There are two basic concepts for using hypertext, hypermedia and multimedia. The first is to develop 'knowledge spaces' and to allow the users to explore these as they wish. This puts the total onus of learning on to the learner as no guidance is given and no structure is applied to the material. If information is to be delivered in this way, the computer would have to be used as part of some larger instructional process in which learning tasks are identified. To simply sit students in front of a computer running a 'knowledge space' would be to deliver information out of context and to remove the possibility of problem solving taking place. If some guidance is to be given to users, then an appropriate instructional strategy must be used. Two of these appear to be worthy of consideration, anchored instruction and Cognitive Flexibility Theory. Part of the initial brief for this paper was to examine ways of using CBI effectively in the teaching of Science. From this perspective, a modified form of Anchored Instruction as proposed by Bransford et al. would seem to have potential. The main drawback with Bransford's system is the use of videodisc, but by using QuickTime as the video source, it is suggested that this could be overcome. Cognitive Flexibility Theory would appear to be ideal for the formation of a well structured mental model. The only problem with this would appear to be the difficulty of determining ways in which the information can be 'criss-crossed'. Both of these strategies appear worthy of further investigation.

	Server: http://scs.une.edu.au Author: Tony Brown Created: 25.6.97 © The University of New England, NSW, Australia