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

One of the main and recognized problems of learning with hypertexts is that learners are easily distracted and end up ‘lost in hyperspace’. As a result, they do not acquire complete and adequate knowledge. In this study, we enhanced a hypertext environment with a graphical overview that represented the basic structure of the domain and we designed the layout 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 showed a more domainrelated 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.