Abstract not found

User-interruption in human-computer interaction (HCI) is an increasingly important problem. Many of the useful advances in intelligent and multitasking computer systems have the significant side effect of greatly increasing user-interruption. This previously innocuous HCI problem has become critical to the successful function of many kinds of modern computer systems. Unfortunately, no HCI design guidelines exist for solving this problem. In fact, theoretical tools do not yet exist for investigating the HCI problem of user-interruption in a comprehensive and generalizable way. This report asserts that a single unifying definition of user-interruption and the accompanying practical taxonomy would be useful theoretical tools for driving effective investigation of this crucial HCI problem. These theoretical tools are constructed here. A comprehensive analysis is conducted through the existing literature. Theoretical constructs from several relevant but diverse fields are identified and discussed. A unifying definition of user-interruption is synthesized. This new definition is supported with an array of postulates, assertions, and a taxonomy of human interruption to facilitate its practical application.

At first glance it seems absurd that busy people doing important jobs should want their computers to interrupt them. Interruptions are disruptive and people need to concentrate to make good decisions. However, successful job performance also frequently depends on people's abilities to (a) constantly monitor their dynamically changing information environments, (b) collaborate and communicate with other people in the system, and (c) supervise background autonomous services. These critical abilities can require people to simultaneously query a large set of information sources, continuously monitor for important events, and respond to and communicate with other human operators. Automated monitoring

Abstract not found

Interruptions can have lower cost if delivered at moments of lower mental workload during task execution, and cognitive theorists have speculated that these moments occur at subtask boundaries. In this article, we empirically test this speculation by examining how workload changes during task execution, focusing on subtask boundaries. In a carefully controlled experiment, users performed several interactive tasks while their pupil dilation, a reliable measure of workload, was continuously measured. The workload data was precisely aligned to the corresponding models of task execution and analyzed. Our principal results include (i) workload changes throughout the execution of a goal-directed task; (ii) workload exhibits momentary decreases at subtask boundaries compared to the preceding subtasks; (iii) the amount of decrease is larger at boundaries higher in the task model; and (iv) different types of subtasks induce different amounts of workload. We situate these findings within resource theories of attention and discuss important implications for interruption management systems.

Adaptive automation refers to technology that can change its mode of operation dynamically. Further, both the technology and the operator can initiate changes in the level or mode of automation. The present paper reviews research on adaptive technology. The paper is intended as a guide and review for those seeking to use psychophysiological measures in design and assessing adaptively automated systems. It is divided into four primary sections. In the first section, issues surrounding the development and implementation of adaptive automation are presented. Because physiological-based measures show much promise for implementing adaptive automation, the second section is devoted to examining candidate indices and reviews some of the current research on these measures as they relate to workload. In the third section, detailed discussion is devoted to electroencephalogram (EEG) and eventrelated potentials (ERPs) measures of workload. The final section provides an example of how p...

The Air Traffic Control Specialist (ATCS) Performance Measurement Database is a compilation of performance measures and measurement techniques that researchers have used. It may be applicable to other human factor research related to air traffic control (ATC). This database is a tool that can be used in conjunction with ATC simulators, generic sector configurations and scenarios, and other procedures used in assessing ATC system safety and effectiveness. Having a set of measures with standardized parameters will increase the reliability of results across experiments and enable comparisons of results across evaluations. At this time, it is unlikely that the database includes all of the measures that are applicable to ATC assessments. However, the database is designed to be an adaptive research tool, and the authors invite your nominations of other measures for the database. 17. Key Words Air Traffic Control Specialist Measurement techniques 18. Distribution Statement This document is available to the public through the National Technical Information Service, Springfield, Virginia, 22161 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Form DOT F 1700.7 (8-72) Reproduction of completed page authorized iii Table of Contents Page Executive Summary........................................................................................................................v 1.

This paper examines a dual-task method for the assessment of mental effort during online searching, having the users engage in two tasks simultaneously. Searching was assigned as a primary task and a visual observation was set up as a secondary task. The study participants were asked to perform two searches, one on the Web and the other in a webbased library system. Perceived search difficulty and mental effort for searching on the two types of systems were compared through participant self-reports, dual-task performance, and search log analysis. After the searches were completed, the subjects reported that library searching was more difficult to conduct and they had to concentrate more than when Web searching. However, the results of dual-task performance do not reveal much difference in mental effort or concentration during searches in the two systems. Rather, they invested mental effort differently when viewing search results and reading retrieved documents. The findings indicate that a dual-task method provides a useful technique to measure mental effort in online searching, and it has a great potential to be used to measure other aspects of information retrieval such as task complexity and multitasking information behavior.

It could be advantageous in many situations for an adaptive hypermedia system to have information about the cognitive load that the user is currently experiencing. A literature review of the methods proposed to assess cognitive load reveals: (1) that pupil size seems to be one of the most promising indicators of cognitive load in applied contexts and (2) that its suitability for use as an on-line index in everyday situations has not yet been tested adequately. Therefore, the aim of the present study was to evaluate the usefulness of the pupil size index in such situations. To this end, pupil diameter and event-related brain potentials were measured while subjects read texts of different levels of difficulty.

Traffic Safety Administration, in the interest of information exchange. The opinions, findings, and conclusions expressed in this publication are those of the author(s) and not necessarily those of the Department of Transportation or the National Highway Traffic Safety Administration. The United States Government assumes no liability for its contents or use thereof. If trade or manufacturers ’ names or products are mentioned, it is because they are considered essential to the object of the publication and should not be construed as an endorsement. The United States