British Journal of Educational Technology Vol 30 No 2 1999 129–140 ©British Educational Communications and Technology Agency, 1999. Published by Blackwell Publishers, 108 Cowley Road, Oxford, OX4 1JF, UKand 350 Main Street, Malden, MA 02148, USA. Cognitive effects of a structural overview in a hypertext Rijk Hofman and Herre van Oostendorp Dr Rijk Hofman got his Masters degree in Psychology from Utrecht University, Department of Psycho- nomics, he is now working for Thieme Publishing Company as developer of multimedia courseware. Dr Herre van Oostendorp is lecturer on the areas of cognitive psychology and cognitive ergonomics at Utrecht University. Address for correspondence: Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, The Netherlands. Tel: +31 30 253 3390; fax: +31 30 253 4511; email: H.vanOostendorp@fss.uu.nl Abstract Disorientation and navigation inefficiency are the consequences of the frag- mented and incoherent structure of most hypertexts. To avoid these negative effects, researchers recommend—among other things—an interface with a structural overview of the relations between sections. Some authors have found that with such an overview, information is looked up faster and remembered better. This study examined whether a structural overview also leads to a deeper understanding. Forty students read a hypertext about the effects of ultraviolet radiation in one of two presentation conditions (structural overview and list). In the list condition, the same topics were mentioned as in the overview con- dition, but just in the format of a list. After reading, they answered textbase questions which measured their recognition and also inference questions supposed to measure their situation model constructed from the information read. The last type of questions indicated the readers’ understanding of the text. On textbase questions, subjects with low as well as high prior knowledge scored equally well in both conditions. In contrast to our expectation, the over- view did not improve the recognition of main points. However, on situation model questions low prior knowledge subjects scored significantly lower in the overview condition than in the list condition. These results supported our hypothesis that a structural overview may hinder the understanding of less knowledgeable readers, because it draws their attention to the textual macro- structure at the expense of attention to the microstructure of the text. Introduction Hypertext is emerging as an increasingly prevalent form of information presentation. The links in this medium make it possible to flexibly combine linear and hierarchical structures of information. Links are connections between sections on different levels