This study investigated the role of various types of content representation devices on the comprehension of an expository hypertext. We hypothesized that hierarchical representations, but not network representations, may help low prior knowledge students organize their representation of the text contents. Forty-seven students with low or high prior knowledge in Social Psychology were asked to read a hypertext using one of three content representations: a hierarchical map, a network map and an alphabetic list. Then, the participants performed a multiple choice comprehension task, a summary task and a concept map drawing task. The hierarchical map improved comprehension for the low knowledge participants at the global, but not at the local level. There was no effect of content representation on the comprehension of high prior knowledge students. We discuss the implications of these results for a theory of the comprehension processes involved in reading hypertext. (C) 2003 Elsevier Science Ltd. All rights reserved.