The relative effectiveness of hypertext and text

A series of two experiments was conducted. In Experiment 1, participant performance when using a hypertext electronic reference system was compared to using a conventional reference book. The links in this hypertext were based on the index entries in the corresponding 529‐page book. Specific topics and particular facts were located much faster and more accurately using the hypertext system than for the book. These advantages increased when participants searched for information that was either not included or referred to indirectly in the index. However, hypertext did not have an advantage over text on learning tasks. The conclusion was that hypertext is superior to text only for “reading‐to‐do” tasks similar to those a designer may perform when consulting a reference book. Experiment 2 compared user performance when the links corresponded exactly to the original index of a 545‐page textbook on ergonomics to performance when the links were generated by computer key‐word searches. Strong advantages were found in speed, accuracy, and subjective ratings for links based on the author's original index. It appears that these latter results can be attributed to the greater focus of the information provided by links based on the author's index. Users spent much less time browsing irrelevant sections of the book.     

Cognitive load in hypertext reading: A review

A process model of hypertext reading was used to generate predictions about the effects of hypertext features on cognitive processing during text navigation and comprehension. We evaluated the predictions of the model with respect to the extant literature, focusing on studies in which versions of hypertexts were compared. Consistent with our predictions, the increased demands of decision-making and visual processing in hypertext impaired reading performance. Individual differences in readers, such as working memory capacity and prior knowledge, mediated the impact of hypertext features. For example, readers with low working memory and low prior knowledge were usually disadvantaged in hypertext. Some benefits were observed for learners with low prior knowledge, however, if the hypertext structure was hierarchical and consistent with that of the knowledge domain. We also surveyed the effectiveness of structural features designed to reduce cognitive load, including graphical overviews, restricted access to links, and visible link types. Complex graphical overviews did not reliably enable learning and navigation, whereas navigational support from restricted access and visible link types were helpful. We identified gaps in the empirical literature and suggested future studies to investigate cognitive processes in hypertext reading.     

Age differences in the performance of hypertext perusal as a function of text topology

The present study examined the extent to which age had impacts on the performance of hypertext browsing and navigation as a function of text topology. Twenty senior adults and 20 younger adults (mean ages = 68.95 and 23.60 respectively) participated in an experiment where three levels of text linearity were manipulated. Results showed the older adult accessed fewer numbers of text nodes than the younger counterpart, which suggests that the aged appear at a disadvantage in browsing breadth. The older adult's less oriented browsing was evidenced by the larger number of nodes repeatedly visited, particularly when the network topology was perused. As for navigation, older people experienced greater disorientation given that they searched more links to locate the target node. This age difference was mainly derived from the disorientation occurring at the hybrid and network levels, with the hybrid condition resulting in the severest navigation confusion due to its mixed text structure. Implications for the design of hypertext that accommodates the age differences are discussed.     

Age differences in the performance of hypertext perusal as a function of text topology

The present study examined the extent to which age had impacts on the performance of hypertext browsing and navigation as a function of text topology. Twenty senior adults and 20 younger adults (mean ages = 68.95 and 23.60 respectively) participated in an experiment where three levels of text linearity were manipulated. Results showed the older adult accessed fewer numbers of text nodes than the younger counterpart, which suggests that the aged appear at a disadvantage in browsing breadth. The older adult's less oriented browsing was evidenced by the larger number of nodes repeatedly visited, particularly when the network topology was perused. As for navigation, older people experienced greater disorientation given that they searched more links to locate the target node. This age difference was mainly derived from the disorientation occurring at the hybrid and network levels, with the hybrid condition resulting in the severest navigation confusion due to its mixed text structure. Implications for the design of hypertext that accommodates the age differences are discussed.     

The user interface in a hypertext, multiwindow program browser

The program browsing problem is discussed, with particular emphasis on a multiple-window user interface and its implications for recording acquired knowledge, navigation, and attention-tracking. Hypertext systems are considered as an implementation of browsing techniques for nonprogram text. A classification scheme for text-viewing systems is offered, and then browsing is discussed as a nonintrusive, static technique for program study.

Multiple techniques are synthesised into a coherent plan for a multiwindow program study tool, based on theories of program browsing and the use of hypertext. A test system, HYBROW, emerged from the plan for studying the application of several hypertext multiple-window techniques to program browsing, especially window replacement. HYBROW is a hypertext, multiple-window program browser. This generic tool is applicable to any source language, although certain aspects of the preprocessing and the hierarchical browser presentation are specific to the C language. The tool permits opening an arbitrary number of text windows into an arbitrary number of files, rapid window switching, multiple-window search, placemarking, automatic screen organisation, and services for the creation, maintenance and production of study notes. An informal usability study was conducted.     

An eye movement analysis of highlighting and graphic organizer study aids for learning from expository text

This study uses eye tracking technology to examine how study aids such as highlighting and graphic organizers affect cognitive processing during learning. Participants were 130 college students randomly assigned to one of five experimental conditions. In the control group, students read a plain text; in two behaviorally passive conditions, students read a text with key words colored in red or read the same text along with a filled-in graphic organizer; and in two behaviorally active conditions, students either highlighted key words in a text or filled in an empty graphic organizer. Students took tests of rote memory (cloze test) and comprehension (summary test). Asking students to fill in a graphic organizer or providing a filled-in graphic organizer resulted in improvements in performance on both tests, whereas asking students to highlight the text or providing highlighted text improved performance only in the rote memory test compared to students who did not receive any study aids. Eye tracking measures showed that highlighting (in both conditions) primed the cognitive process of selecting: students spent more time fixating on those words colored in red compared with the control condition. In contrast, eye tracking measures showed that graphic organizers (in both conditions) primed the cognitive processes of selecting, organizing and integrating since the inclusion of an organizer substantially affected both where their eyes fixated and moved (i.e. transitions) within the text.     

The effects of text structure and prior knowledge of the learner on computer-based learning

This study is an attempt to investigate the effects of document structure and knowledge level of the reader on reading comprehension, browsing, and perceived control. Four types of texts are distinguished, differing in structure (linear text, hierarchical hypertext, mixed hypertext, and generative text). All the materials were on a PC. In all conditions, participants were allowed 1 h to read through the document. After completing the reading part of the experiment, they were asked to fill out the perceived control questionnaire followed by the reading comprehension test. As far as reading comprehension was concerned, knowledgeable participants had higher reading comprehension scores than non-knowledgeable participants only in the linear text. In addition, there were no significant differences in terms of the reading comprehension scores of the knowledgeable participants among the four topologies. However, the performance of non-knowledgeable participants differed with respect to the type of the topology. In particular, non-knowledgeable participants in the hierarchical and generative conditions performed better than those in the other two conditions. With respect to perceived control, the performance of knowledgeable and non-knowledgeable participants was equivalent in all four conditions. The results are discussed in terms of their implications for the computer-based learning.     

Spatial metaphors and disorientation in hypertext browsing

The spatial metaphor can be used as a framework for explaining and designing tools that alleviate disorientation problems in hypertext systems. The approach based on this metaphor would involve developing tools analogous to navigational aids in physical environments and applying analogous concepts from research on human spatial processing and navigation in physical spaces. Research on hypertext browsing with respect to the spatial metaphor is reviewed and contrasted with the larger task context where users are trying to explore, learn, analyse, and summarize the contents of the hypertext space.     

How hypertext fosters children’s knowledge acquisition: The roles of text structure and graphical overview

Children in primary and secondary school are asked to go on the Internet for school purposes while research on hypertext has scarcely investigated how children process and learn from hypertext. We therefore examined how hypertext influences children’s knowledge acquisition from expository text. A group of 71 Dutch children (13 years old) from one secondary school for pre-university education participated in the study. In a within-subjects design with four conditions, we compared: regular linear text, regular text with overview, hypertext, and hypertext with overview. Children’s (a) navigation (i.e., reading time and navigation pattern) and (b) learning (i.e., multiple choice knowledge questions and mind maps) was measured. Although reading times did not differ, the children navigated less linearly in both hypertext conditions than in the regular text with overview condition. The four types of text led to the same deep understanding as measured on the text base level. Analyses of the mind maps, however, showed the children to construct richer situation models after reading hypertext or hypertext with an overview relative to regular linear text and regular text with overview. We therefore conclude that hypertext fosters a deeper level of information processing when appropriately designed relative to regular linear text.     

Reading skills and children’s navigation strategies in hypertext

Prior research has identified two important navigation strategies that have a clear impact on hypertext comprehension: link selection and overview processing strategies. The first relate to the order in which students select hyperlinks while trying to comprehend a hypertext, whereas the second relate to when and for how long students process navigation overviews, a text device that conveys the text structure by displaying sections, titles and their relations. Most prior research in navigation strategies has been conducted with undergraduate students. We extend prior research by exploring the navigation strategies used by sixth-graders while reading a hypermedia system. We also investigate how reading skills relate to the use of navigation strategies, and how both shape students’ comprehension in hypertext. Results from an electronic reading study replicated in sixth-graders the results on navigation strategies previously found in undergraduate samples. In addition, the results revealed that reading skills predicted the use of link selection but not of overview processing strategies. We discuss our results in light of new models of electronic reading proficiency, and propose some instructional guidelines to improve children’ electronic reading proficiency.     

Spatial metaphors and disorientation in hypertext browsing

Abstract

The spatial metaphor can be used as a framework for explaining and designing tools that alleviate disorientation problems in hypertext systems. The approach based on this metaphor would involve developing tools analogous to navigational aids in physical environments and applying analogous concepts from research on human spatial processing and navigation in physical spaces. Research on hypertext browsing with respect to the spatial metaphor is reviewed and contrasted with the larger task context where users are trying to explore, learn, analyse, and summarize the contents of the hypertext space.     

Comprehension and navigation of networked hypertexts

This study aims to investigate secondary school students' reading comprehension and navigation of networked hypertexts with and without a graphic overview compared to linear digital texts. Additionally, it was studied whether prior knowledge, vocabulary, verbal, and visual working memory moderated the relation between text design and comprehension. Therefore, 80 first‐year secondary school students read both a linear text and a networked hypertext with and without a graphical overview. Logfiles registered their navigation. After reading the text, students answered textbased multiple choice questions and drew mindmaps to assess their structural knowledge of each text content. It was found that both textbased and structural knowledge were lower after reading a networked hypertext than a linear text, especially in students with lower levels of vocabulary. Students took generally more time to read the hypertext than the linear text. We concluded that networked hypertexts are more challenging to read than linear texts and that students may benefit from explicit training on how to read hypertexts.     

Hypadapter: An adaptive hypertext system for exploratory learning and programming

We have developed an adaptive hypertext system designed to individually support exploratory learning and programming activities in the domain of Common Lisp. Endowed with domain-specific knowledge represented in a hyperspace of topics, the system builds up a detailed model of the user's expertise which it utilizes to provide personalized assistance. Unlike other work emerging in the field of adaptive hypertext systems, our approach exploits domain and user modelling techniques to support individuals in different ways. The system not only generates individualized presentations of topic nodes, but also provides adaptive navigational assistance for link-based browsing. By identifying and suggesting useful hyperlinks according to the user's knowledge state and preferences, the system encourages and guides exploration. While browsing through the hyperspace of topics, the system analyses the user's navigational behaviour to infer the user's learning progress and to dynamically adapt presentations of topics and links accordingly.     

A Comparative Study of Computer-Based Document Manipulation Techniques

Techniques to aid the manipulation of a computer-based document were tested by a group of 38 novice users. The subjects were given a period of time to browse the document (which employed a simple book metaphor), and were subsequently given a set of goal-related tasks in a question/answer session. The techniques tested were sequential paging, index referral, text find and embedded hypertext links. In the latter case, 3 differing types of link mechanisms were assessed and compared with each other. It was found that sequential paging and index referral were the most commonly used of the techniques. Text find was employed more for goal-related tasks than for browsing. The hypertext link technique was generally unpopular, especially for goal-related tasks. In order to establish the importance of the text find technique, the effect on reading strategies without this facility was also investigated. For browsing operations, an increase in paging and a decrease in hypertext linking was observed. In the case of goal-directed searching, an increase was observed in paging and index referral techniques.     

Hypertext Access and the New Oxford English Dictionary

While hypertext access to the New Oxford English Dictionary would seem to be potentially beneficial, the conversion of such a text to a hypertext document and the generation of semantic links may not be feasible. Rather than attempting either the conversion of the text or the designation and storage of specific hypertext links, a prototype frontend called READER has been developed that provides hypertext access to the Dictionary. The emphasis in this work has been to provide the user with the browsing approach typical of hypertext rather than the more traditional query-oriented approach to accessing full-texts. The prototype is based on a dynamic hypertext model which facilitates browsing through the dynamic instantiation of implicit links existing in the text of the Dictionary.     

Effectiveness of expert semantic knowledge as a navigational aid within hypertext

Hypertext systems parse documents into content nodes connected by machine supported links or relationships. Many hypertext researchers claim that the node-link relationships of hypertext provide an information organization that models the structure of human knowledge and should therefore facilitate information access (Fiderio 1988). Yet, failures of information access occur when users lack an understanding of the overall scope and organization of a hypertext system (Gay and Mazur 1991). To support this understanding, the present research incorporated expert-based domain semantics in the design of prosthetic devices for hypertext navigation. The task domain was documentation for a word processing system. In the first experiment, the pathfinder algorithm (Schvaneveldt 1990) and cluster analysis were used to identify a set of expertbased semantic relationships between word-processing concepts. The results from these analyses contributed to the design of two prostheses to assist hypertext navigation: A hierarchical index and a local semantic browser. These aids were tested in a second experiment, crossing type of on-line documentation (semantically enhanced hypertext or an alphabetically indexed text) with level of subject expertise (novice or expert). Both performance and strategy measures suggest that the semantic prostheses improved the accessibility of information for novice users without hampering expert performance.     

Effectiveness of expert semantic knowledge as a navigational aid within hypertext

Hypertext systems parse documents into content nodes connected by machine supported links or relationships. Many hypertext researchers claim that the node-link relationships of hypertext provide an information organization that models the structure of human knowledge and should therefore facilitate information access (Fiderio 1988). Yet, failures of information access occur when users lack an understanding of the overall scope and organization of a hypertext system (Gay and Mazur 1991). To support this understanding, the present research incorporated expert-based domain semantics in the design of prosthetic devices for hypertext navigation. The task domain was documentation for a word processing system. In the first experiment, the pathfinder algorithm (Schvaneveldt 1990) and cluster analysis were used to identify a set of expertbased semantic relationships between word-processing concepts. The results from these analyses contributed to the design of two prostheses to assist hypertext navigation: A hierarchical index and a local semantic browser. These aids were tested in a second experiment, crossing type of on-line documentation (semantically enhanced hypertext or an alphabetically indexed text) with level of subject expertise (novice or expert). Both performance and strategy measures suggest that the semantic prostheses improved the accessibility of information for novice users without hampering expert performance.     

Application of probability to enhance the performance of fuzzy based mobile robot navigation

This paper presents a new path planning algorithm based on Probability and Fuzzy Logic (PFL) as a duality technique to enhance the performance of Fuzzy Logic alone. Fuzzy Logic interacts with the grading of obstacles existed in the path and probability lies over the decision to move the mobile robot. The fuzzy grading correspondence with the probabilistic decision is the primary function of moving the mobile robot towards the goal and the secondary is path planning which lies over the probability distribution function. The distance–speed combination rule is developed for effective navigation. The single and multiple mobile robot systems have been tested successfully in a dense environment in presence of obstacles (static and dynamic) and moving goal. The obtained results are optimal when compared to other navigational approaches in sense of navigational path length and time in the static and dynamic environment.     

Metadoc: An adaptive hypertext reading system

Presentation of textual information is undergoing rapid transition. Millennia of experience writing linear documents is gradually being discarded in favor of non-linear hypertext writing. In this paper, we investigate how hypertext — in its current node-and-link form — can be augmented by an adaptive, user-model-driven tool. Currently the reader of a document has to adapt to that document — if the detail level is wrong the reader either skims the document or has to consult additional sources of information for clarification. The MetaDoc system not only has hypertext capabilities but also has knowledge about the documents it represents. This knowledge enables the document to modify its level of presentation to suit the user. MetaDoc builds and dynamically maintains a user model for each reader. The model tailors the presentation of the document to the reader. The three-dimensionality of MetaDoc allows the text presented to be changed either by the user model or through explicit user action. MetaDoc is more a documentation reading system rather than a hypertext navigation or reading tool. MetaDoc is a fully developed and debugged system that has been applied to technical documentation.     

Retrieving information from hypertext: issues and problems

One of the most important developments in information science and in information systems in recent years has been the emergence of hypertext as a way of organizing information. Hypertext uses a browsing rather than a searching strategy and hypertext systems have found applications in a number of diverse areas. One of the strengths of using a hypertext system is the freedom it gives to users in the choice of information they wish to see, but this is also one of its drawbacks. This paper examines the effectiveness of hypertext as a way of retrieving information and reviews conventional information retrieval techniques which are the alternative strategy. Previous attempts at combining information retrieval and hypertext are considered and a prototype system outlined which has been developed to generate guided tours for users, to direct them through a hypertext to information they have requested. Finally, how adding this kind of intelligent guidance to a hypertext system would affect its usability as an information system is discussed.