Today the Web-Based Instruction(WBI), a new type of instruction, is developing rapidly in education all over the world with the progress of information technology. Information technology not only changes the form of instruction, but also develops the theory of instructional interaction. Now there are several theories about instructional interaction which are Moore's "transactional distance", Garrison's "communication and control of learner" and Keegan's "Reintegration of the teaching acts", and so on. These theories analyze some aspects of instructional interaction, but they don't describe the instructional interaction systematically. And in practical process of WBI, the use of instructional interaction is not satisfying. So in new type of instruction, creating a systematic and scientific theory of instructional interaction is an imperative issue. In order to make people know the interaction in WBI clearly, the author discusses the meanings of instructional interaction, and gets the definition and role of the instructional interaction through lots of investigation of references, survey on the Web sites and analysis of theories. Then the author gives seven patterns of interaction in WBI ( Self-independence interaction pattern, Group cooperation interaction pattern, Content interaction pattern, Student to Teacher interaction pattern, Student to Student interaction pattern, Synchronous media interaction pattern, Asynchronous media interaction), according to three points of view, which are subject, object and "bridge" of interaction. In succession the author summarizes seven principles of interaction design ( Subjective principle, Purposeful principle, Applicability principle, Conciseness principle, Equality principle, Clear navigator principle, Opening principle). Finally the author gives a rubric of interaction in WBI so as to measure the level of interaction. Through these researches, we can build an integrated and systematic theory of instructional interaction. |