Age and cognitive ability as predictors of computerized information retrieval

This paper presents an empirical investigation of age and cognitive ability as predictors of computerized information retrieval. Upon the basis of age-related changes in cognitive ability, hypotheses were generated relating to the effects of database structure (linear, hierarchical, or network) and node selection method (explicit or embedded menu). In keeping with previous research in other areas of human-computer interaction, there was a significant main effect of age, with older subjects performing more slowly. However, interactive effects of 'question block' indicated that older subjects were at a particular disadvantage in the early stages of task performance. Age differences in processing speed and/or psychomotor skill appeared to be a particularly important factor. Whilst the effects of cognitive ability were generally weak, spatial memory and logical reasoning scores were negatively correlated with information retrieval response times. Although interactions were not significant, trends in the data for all dependent measures suggested that older subjects may be at a disdvantage when using a network structure.     

Age differences in the performance of information retrieval tasks

In two experiments younger (18-25 years) and older (60-70 years) participants performed an information retrieval task in which they searched for the answers to questions in a hierarchical menu structure. Participants' movement speed, spatial ability, spatial memory, working memory capacity and reasoning speed were measured. Results showed older participants to be slower than younger participants on overall latencies on the information retrieval task. This slowing increases with each consecutive step in the menu structure. Regression analysis showed that movement speed, reasoning speed and spatial ability predicted the overall latencies accurately. Modelling the consecutive steps showed that latencies on the first selection are predicted by movement speed and reasoning speed. Memory and spatial measures are predictors for latencies on steps further into the menu structure only. This finding is consistent with increased slowing of older participants for later selections and suggests that deep menu structures are less suited for older users.     

Age differences in the performance of information retrieval tasks

In two experiments younger (18-25 years) and older (60-70 years) participants performed an information retrieval task in which they searched for the answers to questions in a hierarchical menu structure. Participants' movement speed, spatial ability, spatial memory, working memory capacity and reasoning speed were measured. Results showed older participants to be slower than younger participants on overall latencies on the information retrieval task. This slowing increases with each consecutive step in the menu structure. Regression analysis showed that movement speed, reasoning speed and spatial ability predicted the overall latencies accurately. Modelling the consecutive steps showed that latencies on the first selection are predicted by movement speed and reasoning speed. Memory and spatial measures are predictors for latencies on steps further into the menu structure only. This finding is consistent with increased slowing of older participants for later selections and suggests that deep menu structures are less suited for older users.     

Interacting with hypertext: an experimental investigation of navigation tools

The functionality that comes from hypertext has been an important driver in the growth of electronic commerce. The appropriate use of navigation tools and design of Web sites remains, however, an open research question. The objective of this study was to compare the impact of alternative navigation tools on users’ productivity differences in the retrieving of information. The selected navigation tools are: hierarchical design both with and without page hyperlinks, sequential both with and without page hyperlinks and a search engine. A laboratory experiment tested the effect of these navigation tools. A total of 430 subjects were randomly assigned to work with one of the five navigation tools. The productivity outcomes of the subjects were measured in terms of performance on the information retrieval task, search efficiency, and the self-perception of productivity. The task was an information search of medium complexity. An analysis of the results identifies navigation tools to be a contributing factor to users’ productivity.     

How to Overcome Disorientation in Mobile Phone Menus: A Comparison of Two Different Types of Navigation Aids

The current study was concerned with the basic question of how to overcome users' disorientation when navigating through hierarchical menus in small-screen technical devices, as for example mobile phones. In these devices, menu functions are typically organized in a tree structure. Two different navigation aids were implemented into a computer simulation of a real mobile phone (Siemens S45®). The interface of the first navigation aid (the "category" aid) showed the name of the current category as well as a list of its contents. The interface of the other navigation aid (the "tree" aid) was identical to the first except that it also showed the parents and parent–parents of the current of the category and it indented the subcategories to emphasize the hierarchical structure. For the study, 16 younger (23–28 years) and 16 older adults (46–60 years) had to solve 9 common phone tasks twice consecutively to measure learnability. To gain further insight into user characteristics modulating navigation performance and possibly interacting with the utility of the navigation aids, we assessed users' verbal memory and spatial abilities. Dependent variables were task effectiveness (number of tasks solved) and efficiency (time on task, number of returns in menu hierarchy, and returns to the top). The results reveal a consistent and significant advantage of the tree aid for both age groups, an advantage that was larger for users with lower spatial abilities and older adults. In general, older adults had lower verbal memory and spatial abilities, which were found to account for their lower navigation performance. We assume that the strong advantage of the tree aid is due to the spatial information on the menu structure, which thus conveys survey knowledge. This allows users to form an adequate mental representation of the menu. It is recommended to add a navigation aid providing survey knowledge into the displays of small-screen devices to achieve better overall performance.     

Designing an information search interface for younger and older adults

OBJECTIVE: The present study examined Web-based information retrieval as a function of age for two information organization schemes: hierarchical organization and one organized around tags or keywords. BACKGROUND: Older adults' performance in information retrieval tasks has traditionally been lower compared with younger adults'. The current study examined the degree to which information organization moderated age-related performance differences on an information retrieval task. The theory of fluid and crystallized intelligence may provide insight into different kinds of information architectures that may reduce age-related differences in computer-based information retrieval performance. METHOD: Fifty younger (18-23 years of age) and 50 older (55-76 years of age) participants browsed a Web site for answers to specific questions. Half of the participants browsed the hierarchically organized system (taxonomy), which maintained a one-to-one relationship between menu link and page, whereas the other half browsed the tag-based interface, with a many-to-one relationship between menu and page. This difference was expected to interact with age-related differences in fluid and crystallized intelligence. RESULTS: Age-related differences in information retrieval performance persisted; however, a tag-based retrieval interface reduced age-related differences, as compared with a taxonomical interface. CONCLUSION: Cognitive aging theory can lead to interface interventions that reduce age-related differences in performance with technology. In an information retrieval paradigm, older adults may be able to leverage their increased crystallized intelligence to offset fluid intelligence declines in a computer-based information search task. APPLICATION: More research is necessary, but the results suggest that information retrieval interfaces organized around keywords may reduce age-related differences in performance.     

Impacts of navigation structure,task complexity,and users’ domain knowledge on Web site usability—an empirical study

It is essential for designers of Web sites to understand what navigation structure results in better usability for knowledge acquisition tasks of varying complexity and the Web site users with different level of domain knowledge. Literature shows that multiple factors may exert influence on Web site usability. Navigation structure, task complexity, and user domain knowledge level are among of those factors. Hypotheses are developed about the usability of alternative navigation structures, with different task complexity and user domain knowledge level. Experiments are designed and conducted to test these hypotheses in terms of user performance (accuracy, speed) in accomplishing sets of simple and comparatively complex knowledge acquisition tasks. User perceptions of usability are also measured. Two rounds of experimentation are performed, one with participants who have been trained in the domain of production and operations management, the other with participants who have not been trained in this domain. The results show that a usage-oriented hierarchy or a combined hierarchy are navigation structures associated with statistically significantly higher performance usability than a subject-oriented hierarchy, for both simple and relatively complex knowledge acquisition task sets. A statistically significant effect of domain knowledge on the perception aspect of usability is identified. The study contributes to enhancing the comprehension of researchers, practitioners, and educators about design and usability of Web site navigation structures.     

The effects of topology and task complexity on digital‐speech‐desktop interface design and evaluation

Abstract— This study investigated user task performance in terms of three interface proposals (linear, hierarchical, and network type) and task complexities (single‐layered, double‐layered, and triple‐layered). Forty‐two participants (all male), aged 19–23 years, were recruited for the experiment. The results generated from this study reveal that the different degrees of task complexity interacted with the topological structures of the user interfaces. No difference was found among the three topological structures in the single‐layered task. A linear structure resulted in better user performance than network or hierarchical structures in the double‐layered task, while in the triple‐layered task both network and hierarchical structures resulted in better user performance than a linear topological structure. This study provides an example of the application of topological structures in interface design and evaluation. From a practical perspective, the results imply the necessity of alternative or parallel control systems (linear and hybrid topologies) so that the user can shift between structures according to task complexity.     

The effects of hierarchical structure and visualization ability on computerized information retrieval

This study examined the effects of visualization ability on search time in databases with different hierarchical structures. It was designed to determine whether manipulation of the hierarchical structures of information could accommodate the needs of low‐visualization ability users. The task consisted of finding specific “target” files in each of the four different data structures that varied in depth of organization. The study found the expected effects of organizational structure and visualization ability on retrieval time from the database. It did not find any evidence of an interaction between the two variables on performance. The results suggest that individual differences in performance are the result of differences in perceptual speed and that altering the structure of the information in a database is not an effective way to accommodate to low‐visualization ability users.     

A user study of auditory versus visual interfaces for use while driving

This paper describes a user study on interaction with a mobile device installed in a driving simulator. Two new auditory interfaces were proposed and their effectiveness and efficiency were compared to a standard visual interface. Both auditory interfaces consisted of spatialized auditory cues representing individual items in the hierarchical structure of the menu. In the first auditory interface all items of the current level of the menu were played simultaneously. In the second auditory interface only one item was played at a time. The visual interface was shown on a small in-vehicle LCD screen on the dashboard. In all three cases, a custom-made interaction device (a scrolling wheel and two buttons) attached to the steering wheel was used for controlling the interface. The driving performance, task completion times, perceived workload and overall user satisfaction were evaluated. The experiment proved that both auditory interfaces were effective to use in a mobile environment, but were not faster than the visual interface. In the case of shorter tasks, e.g. changing the active profile or deleting an image, the task completion times were comparable for all interfaces; however, both the driving performance was significantly better and the perceived workload was lower when using the auditory interfaces. The test subjects also reported a high overall satisfaction with the auditory interfaces. The latter were labelled as easier to use, more satisfying and more adequate for performing the required tasks than the visual interface. The results of the survey are not surprising as there is a stronger competition for the visual attention between the visual interface and the primary task (driving the car) than in the case of using the auditory interface. So although both types of interfaces were proven to be effective, the visual interface was less efficient as it strongly distracted the user from performing the primary task.     

Information visualization; assisting low spatial individuals with information access tasks through the use of visual mediators

This study investigated the use of visual mediators to facilitate information access by low spatial individuals. Based on theories of adaptive learning and field-dependence, two human-computer interfaces were developed which were intended to compensate for the inability of low spatial individuals to readily construct visual mental models of a menu system's structure. The two compensatory interfaces included: a 2D visual hierarchy and a linear structure. The information search performance of high and low spatial individuals was compared on the two compensatory interfaces and a third challenge match interface, which challenged individuals to construct a mental model of a hierarchical menu system in order to perform efficiently. The visual mediators were successful in accommodating low spatial individuals, as indicated by the lack of any significant performance differences being detected between the high and low spatial groups on the two compensatory interfaces. High spatial individuals outperformed low spatial individuals only when information search tasks required the use of spatial ability in mentally constructing a model of the organization and structure of embedded task information. The key factor in the accommodation process was the elimination of the need to mentally visualize the structure of embedded task information. These results indicate that visualization techniques can be successfully used to enhance the information search performance of low spatial individuals.     

Effects of diversity in cognitive restructuring skills on human-computer performance

Abstract

The objective of this study was to determine if more efficient performance in hierarchical computer environments could be obtained from field-dependent (low technical aptitude) individuals by manipulating information structuring requirements. A three-dimensional (task complexity, quality of integration, and level of differentiation) conceptual model was proposed to explain differences in memory organization which were suggested to lead to computer performance differences. The model was tested with 36 subjects, 18 identified as field-dependent and 18 as field-independent. The subjects performed the information search task under three task conditions, two structured by the experimenter and one by the subjects. The results indicated that the effects of differences in the organization of task information on computer performance time can be controlled for by providing subjects with a period of time dedicated to the acquisition of a system's structure.     

Adapting menu layout to tasks

Menus are an increasingly popular style of user-system interface. Although many aspects of menu design can affect user performance (e.g. item names and selection methods), the organization of items in menus is a particularly salient aspect of their design. Unfortunately, empirical studies of menu layout have yet to resolve the basic question of how menus should be organized to produce optimal performance. Furthermore, a disturbingly common finding has been that any initial effects of menu layout disappear with practice. Thus it is tempting to conclude that menu organization is not important or that it only affects performance during learning. In this paper we present some reasons to doubt this conclusion. In particular, we have found persistent effects of layout with multiple-item selection tasks, in contrast with studies employing a single-item selection paradigm. The results of a controlled study comparing various menu designs (fast-food keyboards) show that the types of tasks to be performed by users must be considered in organizing items in menus and that there may be sustained effects of menu organization with some tasks. In addition, the results of this study support the use of a formal methodology based on user knowledge for menu design. By comparing the performance of subjects using menus designed using our methodology with the performance of subjects using “personalized” menus, we were able to demonstrate the general superiority of our method for designing menus, and for tailoring menus to meet task requirements as well.     

Haptic User Interfaces for the Visually Impaired: Implications for Haptically Enhanced Science Learning Systems

The overall quality of haptic user interfaces designed to support visually impaired students' science learning through sensorial feedback was systematically studied to investigate task performance and user behavior. Fourteen 6th- to 11th-grade students with visual impairments recruited from a state-funded blind school were asked to perform three main tasks (i.e., menu selection, structure exploration, and force recognition) using haptic user interfaces and a haptic device. This study used several dependent measures that are categorized into three types of variables: (a) task performance including success rate, workload, and task completion time; (b) user behavior defined as cursor movements proportionately represented from the user's cursor positional data; and (c) user preference. Results showed that interface type has significant effects on task performance, user behavior, and user preference, with varying degree of impact to participants with severe visual impairments performing the tasks. The results of this study as well as a set of refined design guidelines and principles should provide insights to the future research of haptic user interfaces that can be used when developing haptically enhanced science learning systems for the visually impaired.     

An evaluation of jump-ahead techniques in menu selection

Menu selection systems provide a means of selecting operations and retrieving information which requires little training and reduces the need for memorizing complex command sequences. However, a major disadvantage of many menu selection systems is that experienced users cannot traverse the menu tree significantly faster than novices. A common solution to this problem is to provide the menu selection system with a jump-ahead capability.

The purpose of this research was to evaluate two jump-ahead methods (type-ahead and direct-access). In the type-ahead method the user anticipates a selection on each of several successive menus and enters as many selections at one time as desired. In the direct-access method, each menu frame is assigned a unique name which the user must enter to locate it.

Thirty-two students were given training on an information retrieval system for college course information and were required to learn the two jump-ahead methods in a counterbalanced design. The direct-access method resulted in fewer traversals to learn the system, lower error rates, and reduced learning time. The subjective impressions, obtained from post-experiment questionnaires and oral comments, indicated that the direct-access jump-ahead method was also preferred in a frequently used menu selection system.     

Interface methods for using intranet portal organizational memory information system

In this paper, an intranet portal is considered as an information infrastructure (organizational memory information system, OMIS) supporting organizational learning. The properties and the hierarchical structure of information and knowledge in an intranet portal OMIS was identified as a problem for navigation tools of an intranet portal interface. The problem relates to navigation and retrieval functions of intranet portal OMIS and is expected to adversely affect user performance, satisfaction, and usefulness. To solve the problem, a conceptual model for navigation tools of an intranet portal interface was proposed and an experiment using a crossover design was conducted with 10 participants. In the experiment, a separate access method (tabbed tree tool) was compared to an unified access method (single tree tool). The results indicate that each information/knowledge repository for which a user has a different structural knowledge should be handled separately with a separate access to increase user satisfaction and the usefulness of the OMIS and to improve user performance in navigation.     

Interface methods for using intranet portal organizational memory information system

In this paper, an intranet portal is considered as an information infrastructure (organizational memory information system, OMIS) supporting organizational learning. The properties and the hierarchical structure of information and knowledge in an intranet portal OMIS was identified as a problem for navigation tools of an intranet portal interface. The problem relates to navigation and retrieval functions of intranet portal OMIS and is expected to adversely affect user performance, satisfaction, and usefulness. To solve the problem, a conceptual model for navigation tools of an intranet portal interface was proposed and an experiment using a crossover design was conducted with 10 participants. In the experiment, a separate access method (tabbed tree tool) was compared to an unified access method (single tree tool). The results indicate that each information/knowledge repository for which a user has a different structural knowledge should be handled separately with a separate access to increase user satisfaction and the usefulness of the OMIS and to improve user performance in navigation.     

User perceptions and expectations of an information retrieval system

Performance measures are frequently used to evaluate user friendliness of a system. An equally important, but often overlooked factor is the users' attitudes towards a system. A prototype interface for information retrieval was developed for presenting engineering manuals online. It was tested on a representative sample of the intended end user community. We found that subjects' expectations were based on their experience with printed materials and other computer systems. Familiar search mechanisms (e.g., table of contents, index) were important for getting them started, even though they switched to other mechanisms as they gained more experience with the system. The fact that the index was more detailed than the one in the printed manual was seen by the subjects as critical for speedy and efficient information retrieval. Keyword search of the database was generally the preferred retrieval mechanism. However, some users preferred the index. The 'Table of Contents' which was a tree structured menu based system was found to be of limited use in the electronic medium, in contrast to the printed manual.     

一种面向主题的Web知识检索方法

知识检索研究如何从数据和信息中抽取知识.在数据和信息日益增长的今天,知识检索显得尤为重要.现有的知识检索主要以事先构造好的知识库为基础,需要通过专家来构建和维护用于检索的知识库.然而,人工构建知识库非常耗时而且代价很高,而且,基于事先构造好的知识库的检索结果也被局限于知识库覆盖的范围,不具有动态性和时变性.本文提出了一种基于Web的面向主题的知识检索方法.该方法一方面以开放动态的Web信息为基础,支持动态即时的知识检索;另一方面,以用户选定的主题为中心,从Web信息中动态获取知识,构成与用户主题相关的知识检索结果,不局限于某个特定领域.