The effects of graphical overviews on exploratory behaviour and knowledge acquisition in hypertext environments

A central aspect of designing hypertext for learning concerns the structure of the information in the hypertext and the view the learner is offered of this structure. In this study, a hypertext environment was enhanced with a graphical overview that represented the basic, inherent, structure of the domain and the layout was designed in such a way that learners were unobtrusively encouraged to follow a sequence of exploration that followed the domain structure. This so-called ‘visual’ lay-out was compared with two lay-outs that presented randomly positioned nodes. One of these two lay-outs contained hints (using ‘highlighting’) to stimulate learners to follow a domain related exploration similar to the one incorporated in the visual lay-out. The other (‘control’) lay-out did not provide such hints. Results showed that participants from both the ‘visual’ and the ‘hints’ conditions demonstrated a more domain-related exploration pattern than participants from the ‘control’ condition. Participants in the ‘visual’ lay-out did not show a better recall of the content of the nodes as such, but showed a significantly better acquisition of knowledge of structure than participants from the other two conditions. These data indicate that a visual display conveys knowledge in its own right and that knowledge gained does not depend on the exploration route followed in the hypertext material.