tocauthor: van_Oostendorp_H* : Human-Computer Interaction Bibliography Search

Age-related Differences in the Content of Search Queries when Reformulating Supporting Information Seeking / Karanam, Saraschandra / van Oostendorp, Herre Proceedings of the ACM CHI'16 Conference on Human Factors in Computing Systems 2016-05-07 v.1 p.5720-5730

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Summary: This study investigated the change in the content of the queries when performing reformulations in relation to age and task difficulty. Results showed that both generalization and specialization strategies were applied significantly more often for difficult tasks compared to simple tasks. Young participants were found to use specialization strategy significantly more often than old participants. Generalization strategy was also used significantly more often by young participants, especially for difficult tasks. Young participants were found to reformulate much longer than old participants. The semantic relevance of queries with the target information was found to be significantly higher for difficult tasks compared to simple tasks. It showed a decreasing trend across reformulations for old participants and remained constant for young participants, indicating that as old participants reformulated, they produced queries that were further away from the target information. Implications of these findings for design of information search systems are discussed.

Fostering Information Seeking Paper Session 4: Cognition@Workplace and Problem Solving Support / van Oostendorp, Herre / Aggarwal, Sonal Proceedings of the 2014 Annual European Conference on Cognitive Ergonomics 2014-09-01 p.18

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Summary: Easiness of navigation within a website is an important factor for information seeking performance. Several cognitive models exist that simulate the web-navigation process. These models are based on different information processing components. In this paper we propose a new cognitive model, CoLiDeS++Pic (Comprehension-based Linked model of Deliberate Search), which uses information scent and path adequacy, applies backtracking, and also takes the semantics of pictures into consideration. We hypothesized that in this way information seeking performance can be better modeled when compared to previous models. This was verified by simulating the model on a mock-up website and comparing the results with previous models. The results support our hypothesis. We also present briefly the results of an experiment with tool-support based on the new model CoLiDeS++Pic. The results prove that model-generated support is fostering information seeking performance and helps in search tasks. We further discuss the challenges and advantages of automating navigation support using the proposed model.

Providing Web Credibility Assessment Support Paper Session 6: Instrument Developments / Aggarwal, Sonal / Van Oostendorp, Herre / Reddy, Y. Raghu / Indurkhya, Bipin Proceedings of the 2014 Annual European Conference on Cognitive Ergonomics 2014-09-01 p.29

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Summary: Presence of information from multiple sources on the internet requires evaluating the credibility of the information, before its utilization. Researchers have suggested that internet users experience difficulty in accessing necessary information and do not pay enough attention to its credibility. We present here the design and implementation of an automated Web Credibility Assessment Support Tool (WebCAST) that considers multiple factors (type of website, popularity, sentiment, date of last update, reputation and review based on users' ratings reflecting personal experience) for assessing the credibility of information and returns a summary indication of the credibility of a website. We use Potentially All Pairwise RanKings of all possible Alternatives (PAPRIKA) method of Multi-Criteria Decision Analysis (MCDA) to give weights to the scale values on each factor, representing the relative importance of the attributes. An empirical evaluation of the tool was conducted by computing the correlation between the tool-generated credibility scores and that of human judges. The correlation was found to be 0.89, thus verifying the validity of the tool. In the future the proposed tool can be made useful to students in their learning process of credibility assessment.

Navigating in a virtual environment with model-generated support Cognitive support / van Oostendorp, Herre / Karanam, Saraschandra Proceedings of the 2013 Annual European Conference on Cognitive Ergonomics 2013-08-26 p.17

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Summary: Though the cognitive processes controlling user navigation in virtual environments as well as in websites are similar, cognitive models of web-navigation have never been used for generating support in virtual environment navigation. We created a simulated 3D building of a hospital and presented users various navigation tasks under two conditions: a control condition and a model-generated support condition. Mean task-completion time and disorientation were recorded. It was found that the cognitive model used can simulate the navigation behavior of participants and also that with model-generated support participants took significantly less time to reach their destination and were significantly less disoriented. The impact of providing model-generated support on disorientation was especially higher for users with low spatial ability. We demonstrated that it is possible to generate tools for navigation in virtual environments using cognitive models developed for web-navigation.

Interaction of textual and graphical information in locating web page widgets Articles / Karanam, Saraschandra / van Oostendorp, Herre / Melguizo, Mari Carmen Puerta / Indurkhya, Bipin Behaviour and Information Technology 2013-05-01 v.32 n.5 p.503-515

Link to Article at Taylor & Francis

Summary: Current models of web navigation focus only on the influence of textual information and ignore the role of graphical information. We studied the differential role of text and graphics in identifying web page widgets classified into two kinds: textual and graphical. Four different versions of web pages were created by systematically removing textual and graphical information from each page. The task of the participants was to locate either textual or graphical widgets on the displayed web page. Results show that for any widget, the task-completion time and the number of clicks were significantly less in web pages with graphics than in those with no graphics. This demonstrates the importance of graphical information. However, textual information is also important because performance in locating graphical widgets under no-graphics conditions was better when text was present than with no text. Since, for identifying graphical widgets, text and graphics interact and complement each other, we conclude that cognitive models on web navigation should include the role of graphical information next to textual information.

CoLiDeS+ Pic: a cognitive model of web-navigation based on semantic information from pictures / van Oostendorp, Herre / Karanam, Saraschandra / Indurkhya, Bipin Behaviour and Information Technology 2012-01 v.31 n.1 p.17-30

Link to Article at Taylor & Francis

Summary: Comprehension-based linked model of deliberate search (CoLiDeS) + Pic is a cognitive model of web-navigation that takes into account the semantic information from graphical elements present on a web-page to compute the information scent value of the hyperlinks. The model is based on CoLiDeS, which has a two-phase processing cycle: (a) attention phase, which first parses the web-page and focuses attention on the region of the web-page that is semantically most similar to the goal, and (b) action-selection phase, which evaluates the available actions in the focused region and selects a particular action such as clicking a link. The graphical elements are important both for attracting attention to a region of the web-page and for communicating semantic meaning that may alter or enhance the meaning of the hyperlink labels. In the first part of this article, we give a theoretical explanation of the CoLiDeS + Pic model and describe the methodology followed to implement it. In the second part, we run a simulation on a mock-up website and evaluate the effect of pictures on information scent of hyperlinks by means of the CoLiDeS + Pic model on basis of the simulation results. It was found that CoLiDeS + Pic with highly relevant pictures increases the values of information scent of task-relevant hyperlinks, and therefore it increases the probability of selecting those hyperlinks compared to CoLiDeS (without pictures) or CoLiDeS + Pic with lowly relevant pictures. These results confirm the importance of including information from pictures into the modelling of web-navigation.

Evaluating CoLiDeS + Pic: the role of relevance of pictures in user navigation behaviour / Karanam, Saraschandra / van Oostendorp, Herre / Indurkhya, Bipin Behaviour and Information Technology 2012-01 v.31 n.1 p.31-40

Link to Article at Taylor & Francis

Summary: CoLiDeS + Pic is a cognitive model of web-navigation that incorporates semantic information from pictures intoCoLiDeS. In our earlier research, we have demonstrated that by incorporating semantic information from pictures, CoLiDeS + Pic can predict the hyperlinks on the shortest path more frequently, and also with greater information scent, compared to earlier cognitive models of web-navigation like CoLiDeS that relied only on textualinformation from hyperlinks. In this article, we investigate the following research questions. First, would the increase in information scent have an impact on the actual user navigation behaviour? Second, do users actually follow the navigation path predicted by CoLiDeS + Pic? In other words, would CoLiDeS + Pic predict actual user navigation behaviour more accurately than CoLiDeS? We investigate these questions by varying the relevance of pictures on a web page and studying the impact of varying relevance on the user navigation patterns. We found that under the highly relevant picture condition, users were more accurate and took less time to finish their tasks. Also, under the highly relevant picture condition, CoLiDeS + Pic predicts significantly greater number of actual user clicks. There was no significant difference in model predictions between the lowly relevant picture condition and no-picture condition. These results validate the predictions made by CoLiDeS + Pic.

Seeking information online: the influence of menu type, navigation path complexity and spatial ability on information gathering tasks / Melguizo, Mari Carmen Puerta / Vidya, Uti / van Oostendorp, Herre Behaviour and Information Technology 2012-01 v.31 n.1 p.59-70

Link to Article at Taylor & Francis

Summary: We studied the effects of menu type, navigation path complexity and spatial ability on information retrieval performance and web disorientation or lostness. Two innovative aspects were included: (a) navigation path relevance and (b) information gathering tasks. As expected we found that, when measuring aspects directly related to navigation performance such as time and lostness, path complexity plays an important role. During navigation, expandable menus are more beneficial than sequential menus, especially for people with low spatial skills and when the semantic similarity between the information goal and the navigation path is high. When measuring aspects only related to information retrieval, once navigation has occurred, the effects of menu type depend on the spatial skills and the difficulty of the task itself. Participants with high skills perform well in all conditions. Participants with low spatial skills benefit from the use of expandable menus showing only problems with the sequential menu and when the tasks demanded more than simply combining information from different locations on a web page. The opposite pattern found with participants with medium spatial skills needs further research.

Stimulation of activity in online communities Collaboration at a distance / van Oostendorp, Herre / van Varik, Ferdy Proceedings of the 2011 Annual European Conference on Cognitive Ergonomics 2011-08-24 p.163-170

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Summary: Motivation -- Identify the factors that relate to the activity within a community, to derive a framework which can be used to stimulate activity in both new and existing online communities and to test the effectiveness of the framework.
    Research approach -- The relations between 9 metrics of community success and 26 community properties have been identified in a statistical analysis of 58 online communities. Guidelines derived from this analysis have been applied to a case study.
    Findings/Design -- 13 factors have been identified. These factors have been incorporated into the Community Activity (CA) framework and 11 guidelines for stimulating online community activity. Application of this framework to an existing online community resulted in more interest in parts of the website and increased actual usage.
    Research limitations/Implications -- Only (health-based) social communities have been used in the analysis. Generalisation to other kinds of online communities (e.g. technical) may require additional research.
    Originality/Value -- The research provides an insight as to why communities may fail, by presenting factors that may have a positive or negative effect on member activity.
    Take away message -- Functionality available within online communities may influence member activity. Place focus on privacy options, notifications and member profiles.

The role of Game Discourse Analysis and curiosity in creating engaging and effective serious games by implementing a back story and foreshadowing Cognitive Ergonomics for Situated Human-Automation Collaboration / Wouters, Pieter / van Oostendorp, Herre / Boonekamp, Rudy / van der Spek, Erik Interacting with Computers 2011-07 v.23 n.4 p.329-336

10.1016/j.intcom.2011.05.001

Keywords: Computer games / Game design / Discourse analysis / Engagement / Curiosity / Entertainment

Link to Article at sciencedirect

Summary: A challenge for serious games designers is to integrate learning with entertainment. For this purpose, the generation of curiosity using the foreshadowing/back story technique is promising. To implement this technique we propose the Game Discourse Analysis (GDA) which discerns between information flow (i.e. the sequence of information elements in a chronological order) and game discourse (i.e. the manipulation of the information flow to make the game more engaging and effective). We elaborate on the GDA and describe how two of the authors applied it in order to implement foreshadowing/back story in the game ReMission. The GDA was found to have potential as a communication tool for multidisciplinary design teams. Also, two problems were signaled: (1) creating an information flow is laborious and designers may benefit from automating parts of the GDA; (2) substantial deviations from the optimal information flow by players' actions may interfere with the intention of the game discourse. Additionally, in an experiment we tested the impact of this GDA supported manipulation on engagement (curiosity) and learning. We found that the GDA-supported foreshadowing/back story yielded more curiosity, but that it did not yield learning.

The role of content in addition to hyperlinks in user-clicking behavior Information seeking and navigation / Karanam, Saraschandra / van Oostendorp, Herre / Indurkhya, Bipin Proceedings of the 2010 Annual European Conference on Cognitive Ergonomics 2010-08-25 p.125-131

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Summary: Motivation -- Cognitive models of web-navigation such as CoLiDeS, CoLiDeS+, SNIF-ACT compute the correct hyperlink by using information from the hyperlink text alone and ignore all other information on a web-page. This paper focuses on verifying the validity of this assumption by investigating the role played by the main content in addition to hyperlink text on the deciding the correct hyperlink.
    Research approach -- A mock-up website with two conditions: (i) with main content and hyperlinks and (ii) without main content but with hyperlinks was created. 18 students performed 8 information retrieval tasks on this mock-up website.
    Findings/Design -- The results showed that the user-click behaviour with or without main content remained largely the same. The same links were selected by users in both conditions. Also, the same amount of time was spent on the commonly selected links in both conditions.
    Research limitations/Implications -- We restrict ourselves to the role of main content in this experiment and did not study the impact of other factors like pictures.
    Originality/Value -- These results provide an empirical proof to the assumption CoLiDeS makes in its 3rd and 4th phases of focusing and selecting.
    Take away message -- Implication of the results is that one needs to study deeper the relevance/quality of wording used for hyperlinks in relation to the main content. We assume that if the wordings (of the links) are relevant or familiar to the user, the influence of main content would be negligible but if they are less relevant or unfamiliar, the content becomes more influential.

Game design: the mapping of cognitive task analysis and game discourse analysis in creating effective and entertaining serious games Methods, tools, and methodologies / Wouters, Pieter / van Oostendorp, Herre / van der Spek, Erik D. Proceedings of the 2010 Annual European Conference on Cognitive Ergonomics 2010-08-25 p.287-293

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Summary: Motivation -- Game design and instructional design have to be reconciled in order to create effective and engaging serious games. However, a methodology for this purpose is not yet available.
    Research approach -- Such a methodology should meet two requirements. It should provide (1) a taxonomy of categories that can be used to describe both information related to learning objectives (e.g., cognitive skills) and information describing the dynamics of the game, (2) guidelines to trigger learning naturally in the game.
    Findings/Design -- Our proposed methodology comprises two stages. First, a cognitive task analysis (CTA) is made of the task or the domain that has to be learned. Second, the information of this analysis has to be integrated with game-related information elements using our Game Discourse Analysis (GDA). We developed a taxonomy of information elements, types of relations and aggregates of information elements which form the tools for the GDA. We showcase the methodology in the domain of triage. In addition, we present two pilot studies to validate our claims.
    Research limitations/Implications -- Although the two pilot studies provide some evidence for our claims, more research is needed.
    Originality/Value -- Currently, the community of (serious) games designers lacks an instrument to design engaging serious games, to communicate about these games and to make comparisons between serious games. Our methodology fills in this gap.
    Take away message -- Serious game design requires a methodology (GDA) that enables designers to describe, visualize, understand and manipulate the information flow in games in order to create effective and engaging serious games.

Eye Movement as Indicators of Mental Workload to Trigger Adaptive Automation Cognitive Load and Performance / de Greef, Tjerk / Lafeber, Harmen / van Oostendorp, Herre / Lindenberg, Jasper FAC 2009: 5th International Conference on Foundations of Augmented Cognition. Neuroergonomics and Operational Neuroscience 2009-07-19 p.219-228

Keywords: mental workload; adaptive automation; eye movement; pupil diameter; saccade; fixation time

Link to Digital Content at Springer

Summary: This research describes an approach to objective assessment of mental workload, by analyzing differences in pupil diameter and several aspects of eye movement (fixation time, saccade distance, and saccade speed) under different levels of mental workload. In an experiment, these aspects were measured by an eye-tracking device to examine whether these are indeed indicators for mental workload. Pupil diameter and fixation time both show a general significant increase if the mental workload increases while saccade distance and saccade speed do not show any significant differences. This assessment of mental workload could be a trigger for aiding the operator of an information system, in order to meet operational requirements.

The effects of the number of links and navigation support on cognitive load and learning with hypertext: The mediating role of reading order / Madrid, R. Ignacio / Van Oostendorp, Herre / Melguizo, Mari Carmen Puerta Computers in Human Behavior 2009-01 v.25 n.1 p.66-75

Keywords: Hypertext comprehension

Keywords: Cognitive load

Keywords: Navigation support

Keywords: Learning

Link to Article at sciencedirect

Summary: Problems in learning with hypertext systems have been claimed to be caused by high levels of disorientation and cognitive load. This was recognized by DeStefano and LeFevre [DeStefano, D., & LeFevre, J. -A., (2007). Cognitive load in hypertext reading: A review. Computers in Human Behavior, 23(3), 1616-1641.] who predicted an increase of cognitive load and impairment of learning for hypertexts with a higher number of links per page. From a practical perspective, several navigation support techniques, such as providing link suggestions, have been proposed for guiding learners and reducing cognitive overload. In an experiment, we tested DeStefano and LeFevre's predictions as well as the usefulness of link suggestions. Participants used different versions of a hypertext, either with 3-links or 8-links per page, presenting link suggestions or not. We tested their cognitive load and learning outcomes. Results showed that there was a benefit of using link suggestions for learning, but no effect of number of links on learning was found. Moreover, the effects of our manipulations on cognitive load were mediated by the reading order that participants selected. Implications for research and the design of navigation support systems are discussed.

Predicting and solving web navigation problems Posters, demonstrations, and the reading room (1) / Melguizo, Mari Carmen Puerta / van Oostendorp, Herre / Juvina, Ion Proceedings of the Eighteenth ACM Conference on Hypertext and Hypermedia 2007-09-10 p.47-48

ACM Digital Library Link

Summary: In the first experiment we explored the ability of different objective and subjective measures to predict user's success in finding information in a website. The results indicate that the subjective measure of lostness seems to be a better predictor of task performance than any of the objective measures. In the second experiment the probability of getting lost was reduced by presenting navigation support generated by the cognitive model CoLiDeS+, a model of web navigation that describes step-by-step which information presented on the screen is attended to and selected. CoLiDeS+ could be used as a software agent that automatically offers navigation suggestions in real time.

Guidance in the interface and transfer of task performance Decision making, cognition, and problem solving / van Nimwegen, Christof / van Oostendorp, Herre Proceedings of the 2007 Annual European Conference on Cognitive Ergonomics 2007-08-28 p.225-232

ACM Digital Library Link

Summary: Motivation -- Previous research has shown that a "guided" interface where relevant task information is shown on screen (externalization) can result in worse performance than an "unguided" interface where users have to think more for them selves (internalization). In this study we investigate transfer of task performance. We will investigate whether switching from an "unguided" to a "guided" interface results in better performance than if it were the other way around. We also investigate whether the unguided interface enhances performance on a (near) transfer task.
    Research approach -- We conducted an experimental study in two phases: an initial phase, and a transfer phase. In the initial phase, 45 students divided in a "guided" and "non-guided" condition solved a series of problems with the respective interfaces. After, in the transfer phase, they were presented with the opposite interface. This could happen during the first transfer task, or during the second one.
    Findings -- The unguided interface resulted in more efficient performance than the guided interface. We attribute this to the fact that the unguided interface provokes more active thinking and contemplation. Furthermore, switching from an unguided to a guided interface had no effect on efficiency, while the other way around, it had a negative effect on efficiency. Finally, performance on a first transfer task with an unguided version after having worked with a guided version caused worse performance than other combinations.
    Take away message -- Deeper levels of thought instigated by the unguided interface, causes more solid knowledge and stronger, more flexible strategies. This is also reflected when doing a transfer task. This can be important in situations where learning itself is the aim, but one can also think of situations where making errors generates a high cost.

Using a cognitive model to generate web navigation support / van Oostendorp, Herre / Juvina, Ion International Journal of Human-Computer Studies 2007 v.65 n.10 p.887-897

Keywords: Cognitive modelling; Individual differences; Web navigation; Navigation support; Information scent

Link to Article at ScienceDirect

Summary: A computational cognitive model of web navigation is proposed. Based on theories and models of text comprehension and web navigation, the plausibility of the proposed model is discussed. The model was used to generate navigation support and this support was offered to users in real time during their navigation sessions, in two experiments. In the first experiment navigation support was offered in the auditory modality and it had a positive effect on user's task performance, especially for users with low spatial abilities. In the second experiment navigation support was offered in the visual modality and users positively evaluated it. Users navigated in a more structured way, judged the system as more usable, and perceived themselves as less disoriented. Support did also here lead to better task performance. Finally, some aspects concerning further enhancement of the validity of the proposed model and its practical relevance are discussed.

The paradox of the assisted user: guidance can be counterproductive Awareness and presence / van Nimwegen, Christof C. / Burgos, Daniel D. / van Oostendorp, Herre H. / Schijf, Hermina H. J. M. Proceedings of ACM CHI 2006 Conference on Human Factors in Computing Systems 2006-04-22 v.1 p.917-926

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Summary: This paper investigates the influence of interface styles on problem solving performance. It is often assumed that performance on problem solving tasks improves when users are assisted by externalizing task-related information on the interface. Although externalization requires less recall and relieves working memory, it does not instigate planning, understanding and knowledge acquisition. Without this assistance, task-information must be internalized, stored in the user's memory, leading to more planning and thinking and perhaps to better performance and knowledge. Another variable that can influence behavior is "Need for Cognition" (NFC), the tendency to engage in effortful cognitive tasks. We investigated the effects of interface style and cognitive style on performance using a conference planning application. Interface style influenced behavior and performance, but NFC did not. The internalization interface led to more planful behavior and smarter solutions. When planning and learning are the aim, designers should thus beware of giving a user (too) much assistance. Understanding how people react to interface information can be crucial in designing effective software, especially important in the areas of education and learning.

Bricks: The Building Blocks to Tackle Query Formulation in Structured Document Retrieval Structure/XML / van Zwol, Roelof / Baas, Jeroen / van Oostendorp, Herre / Wiering, Frans Proceedings of ECIR'06, the 2006 European Conference on Information Retrieval 2006-04-10 p.314-325

Link to Digital Content at Springer

Summary: Structured document retrieval focusses on the retrieval of relevant document fragments for a given information need that contains both structural and textual aspects.
We focus here on the theory behind Bricks, a visual query formulation technique for structured document retrieval that aims at reducing the complexity of the query formulation process and required knowledge of the underlying document structure for the user, while maintaining full expression power, as offered by the NEXI query language for XML retrieval.
In addition, we present the outcomes of a large scale usability experiment, which compared Bricks to a keyword-based and a NEXI-based interface. The results show that participants were more successful at completing a search assignments using Bricks. Furthermore, we observed that the participants were also able to successfully complete complex search assignments significantly faster, when using the Bricks interface.

Individual differences and behavioral metrics involved in modeling web navigation / Juvina, Ion / van Oostendorp, Herre Universal Access in the Information Society 2006 v.4 n.3 p.258-269

Keywords: Web navigation - Individual differences - Navigation metrics

Link to Digital Content at SpringerLink

Summary: This paper presents an empirical study aiming at investigating individual differences and behavioral metrics involved in modeling web navigation. Factors that have an influence on web navigation behavior were identified with the aid of task analysis, and their relevance in predicting task outcomes (performance, satisfaction, perceived disorientation) was tested with the aid of multiple regression analysis. Several types of navigation metrics were calculated based on web logging data and used as indicators of user characteristics and task outcomes. Results show that spatial-semantic cognitive mechanisms seem to be crucial in adequately performing web navigation tasks. The fact that user characteristics and task outcomes can be estimated with reasonable accuracy based on navigation metrics suggests the possibility of building adaptive navigation support in web applications.

Cognitive Model Working Alongside the User / Juvina, I. / van Oostendorp, H. Proceedings of the HCI'05 Conference on People and Computers XIX 2005-09-05 p.409-420

Individual Differences and Behavioral Aspects Involved in Modeling Web Navigation Part I: Implementing User Diversity / Juvina, Ion / van Oostendorp, Herre Proceedings of the 8th ERCIM Workshop on 'User Interfaces for All' 2004-06-28 p.77

Link to Digital Content at SpringerLink

Summary: This paper presents an empirical study aiming at investigating individual differences and behavioral aspects involved in modeling web navigation. Factors that have an influence on web navigation behavior were identified with the aid of task analysis and their relevance in predicting task outcomes (performance, satisfaction, disorientation) was tested with the aid of multiple regression analysis. Several types of navigation metrics were calculated based on web logging data and used as indicators of user characteristics and task outcomes. Results show that spatial-semantic cognitive mechanisms seem to be crucial in adequately performing web navigation tasks. The fact that user characteristics and task outcomes can be estimated with reasonable accuracy based on navigation metrics suggests the possibility of building adaptive navigation support in web applications.

Human Factors in Web-assisted Personal Finance Human-centred computing : cognitive, social and ergonomic aspects / Juvina, I. / Van Oostendorp, H. Proceedings of the Tenth International Conference on Human-Computer Interaction 2003-06-22 v.3 p.477-481

Designing Multimedia for Human Needs and Capabilities / van Oostendorp, Herre / Preece, Jenny / Arnold, Albert G. Interacting with Computers 1999 v.12 n.1 p.1-5

Keywords: Human values; Usability; Multimedia

Summary: The central tenet of HCI is to ensure that software and hardware design supports users doing their tasks. Most of the papers in this Special Issue go one step beyond designing for usability -- they also address design issues related to supporting human values. As computer usage becomes more diverse both in terms of the range of users and types of applications, human values such as democracy will become increasingly important and controversial, especially, as the number of people coming onto the Internet increases. For example, the issue of computer haves and have nots is well known, but governments are only just starting to think through its implications in terms of future policy. In addition, understanding users' affective responses to systems and how emotions are conveyed across networks is starting to gain designers' attention. Brenda Laurel's company, Purple Moon, is a clear example of the perceived need of designing to support users' emotional needs, in this case, teenage girls.

The Influence of Structure and Reading-Manipulation on Usability of Hypertexts / van Nimwegen, Christof / Pouw, Miriam / van Oostendorp, Herre Interacting with Computers 1999 v.12 n.1 p.7-21

Keywords: Hypertext; Usability; Reading manipulation; Structure

Summary: This study investigates the influence of structure and reading-manipulation, and more importantly, the interaction between these two variables on usability of hypertexts. Four types of hypertexts are distinguished, differing in structure (hierarchical, or hierarchical with partial linearity) and reading-manipulation (scrolling or paging). A fifth extra hypertext containing a hierarchical structure with partial linearity and both paging and scrolling was also investigated. The information itself, a city guide about Utrecht with cultural and tourist information, was exactly the same in all hypertexts. Three aspects of usability were examined: efficiency, ease of learning and user-satisfaction. These aspects are measured by performance on 24 search tasks and a task reflecting insight into the structure of the hypertext. Also, questions about the structure of the hypertext and satisfaction with the system had to be answered. The results indicated that structure and reading-manipulation did not interact. There were, however, significant main effects of structure and reading-manipulation. A purely hierarchical structure was frequently more usable than a hierarchical structure with partial linearity, and scrolling appeared to be more useful than paging. The fifth alternative hypertext seemed slightly more usable than the hypertexts with linearity, but less usable than purely hierarchical hypertexts. The findings combined suggest that a purely hierarchical hypertext with scrolling is most useful, probably because this structure and kind of reading-manipulation both provide a clear insight into the structure of the hypertext. We assume this insight to be necessary for adequate performance.