Linking and timing what is to be presented to the learner is particularly important in multimedia educational environments, especially when the same piece of material can be presented to the learner in different media, often more than once. This article addresses the linking and timing attributes of the presentation of learning material in multimedia educational systems by way of a control in teaching strategy selection. The control mechanism is illustrated through the model for teaching strategy selection. The model is based on factors that affect human teachers in their teaching strategy selection, which in turn governs the decision of which piece of material to present, and the timeliness of such. The benefits of the model are demonstrated through ARISTOTLE, a multimedia education system in which the model is deployed.
User disorientation has frequently been discussed in research in multimedia. The freedom in user navigation and the division of information into nodes may disturb the construct provided in conventional linear structures (Chapman & Chapman, 2000). This undermines the benefits of the flexibility of information presentation in multimedia educational systems. Reliance on commercial concerns, such as business involvement and marketability, has prompted a generation of high-street multimedia educational packages, which employ attractive interface designs, yet without much expectations on specific learning goals, less to the activities and information essential to the achievement of the specific goals, and none at all to the formative evaluation and revision of the learner's progress against specific learning goals (Tong & Agius, 1999). The main weakness of multimedia systems in educational environments stems from the loosely-structured links between the different pieces of learning materials, and the lack of educa tional validity for how the pieces of learning material should be related, and when a particular piece of material should be presented.
In multimedia systems in general, the way in which information is fundamentally associated in a system is predefined by the author in a hypermedia structure by way of nodes and links. The order and the timeliness of the presentation, that is, leaving one presentation for the next, is executed by the user. The importance of linking and timing presentations has been addressed by many in the field of multimedia and hypermedia, but often not directly related to educational settings (Courtiat & Oliveira, 1996; Fernando, Soares, Rodrigues, & Muchaluat-Saade, 2000; Hardman, Bulterman, & Rossum, 1993a; Rutledge, Ossenbruggen, Hardman, & Bulterman, 1999). In the education arena, the importance of these two issues has been investigated by research in computer-based instructional systems, as well as research in human teaching. To this end, the emphasis is on the combined implication of the two issues, "when" to present "what," and why (Tong, 1999).
This article aims to define the linking and timeliness of information presentation in multimedia educational systems by employing a set of mechanisms which governs teaching strategy selection. It does not propose new research in computational links and their representations in hypermedia. Its objective is to demonstrate how the flow and the timeliness of presentations in multimedia educational settings can be improved with instructional reasoning. The proposition of a control in teaching strategy selection derived from the fact that teaching strategies are conceptual means through which the teacher imparts material to the learner. The links and timeliness of the physical presentation of the learning material can be conceptually structured through the use of different teaching strategies. The rest of the article is organised as follows. The next section reviews related work in the linking and timeliness of information presentation in multimedia systems, as well as the use of teaching strategies in educational systems. …