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.

Interruptions can cause people to make mistakes or errors during human--computer interaction (HCI). Interruptions occur as an unavoidable side-effect of some important kinds of human computer-based activities, for example, (a) constantly monitor for unscheduled changes in information environments, (b) supervise background autonomous services, and (c) intermittently collaborate and communicate with other people. Fortunately, people have powerful innate cognitive abilities that they can potentially leverage to manage multiple concurrent activities if they have specific kinds of control and interaction support. There is great opportunity, therefore, for user-interface design to increase people's ability to successfully handle interruptions, and prevent expensive errors. The literature contains very little concrete design wisdom about how to solve the interruption problems in user interfaces (UIs). Coordination support, however, is identified as a most important design topic. This article presents the results of an empirical investigation to compare basic design solutions for coordinating human interruption in computer -based multitasks. A theory-based taxonomy of human interruption is used

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

This paper suggests the use of non-speech sound output to enhance the graphical display of information can overcome overload. The question is how to integrate the display of sound and graphics to capitalise on the advantages each offer. The approach described here is to integrate sound into the basic components of the human-computer interface. Two experiments are described where non-speech sounds were added to buttons and scrollbars. Results showed sound improved usability by increasing performance and reducing time to recover from errors. Subjective workload measures also showed a significant reduction. Results from this work show that the integrated display of graphical and auditory information can overcome information overload

Future human-computer interfaces will use more than just graphical output to display information. In this paper we suggest that sound and graphics together can be used to improve interaction. We describe an experiment to improve the usability of standard graphical menus by the addition of sound. One common difficulty is slipping off a menu item by mistake when trying to select it. We designed and experimentally evaluated sonically-enhanced menus to try and overcome this problem. The results from the experiment showed a significant reduction in the subjective effort required to use the new menus along with significantly reduced error recovery times. A significantly larger number of errors were also corrected with sound.

A significant proportion of early HCI research was guided by one very clear vision: that the existing theory base in psychology and cognitive science could be developed to yield engineering tools for use in the interdisciplinary context of HCI design. While interface technologies and heuristic methods for behavioral evaluation have rapidly advanced in both capability and breadth of application, progress toward deeper theory has been modest, and some now believe it to be unnecessary. A case is presented for developing new forms of theory, based around generic “systems of interactors. ” An overlapping, layered structure of macro- and microtheories could then serve an explanatory role, and could also bind together contributions from the different disciplines. Novel routes to formalizing and applying such theories provide a host of interesting and tractable problems for future basic research in HCI.

This paper describes the design of user-interface widgets that include non-speech sound. Previous research has shown that the addition of sound can improve the usability of human-computer interfaces. However, there is little research to show where the best places are to add sound to improve usability. The approach described here is to integrate sound into widgets, the basic components of the human-computer interface. An overall structure for the integration of sound is presented. There are many problems with current graphical widgets and many of these are difficult to correct by using more graphics. This paper presents many of the standard graphical widgets and describes how sound can be added. It describes in detail the usability problems with the widgets and then the non-speech sounds to overcome them. The non-speech sounds used are earcons. These sonically-enhanced widgets allow designers who are not sound-experts to create interfaces that effectively improve usability and have coherent and consistent sounds.

www.dcs.gla.ac.uk/~stephen/ Future human-computer interfaces will use more than just graphical output to display information. In this paper we suggest that sound and graphics together can be used to improve interaction. We describe an experiment to improve the usability of standard graphical menus by the addition of sound. One common difficulty is slipping off a menu item by mistake when trying to select it. One of the causes of this is insufficient feedback. We designed and experimentally evaluated a new set of menus with much more salient audio feedback to solve this problem. The results from the experiment showed a significant reduction in the subjective effort required to use the new sonically-enhanced menus along with significantly reduced error recovery times. A significantly larger number of errors were also corrected with sound. 1.

Requirements that involve the usability of systems can be properties of interactions rather than systems alone. We demonstrate this proposition by means of four examples and then suggest how a notation like CSP may be used to provide a framework for considering different modelling approaches. Interaction requirements that relate to multi-windowed systems, walk up and use systems and dynamic systems such as power stations are considered. The paper shows how models provide different representations into which advice from the different disciplines of human computer interaction may be applied. 1 Introduction An important class of requirements relating to the specification and implementation of computer systems is concerned with usability. Within the general category of usability is contained more specific concerns such as ease of use, ease of learning, error visibility, error tolerance and error resistance. In order to interpret usability requirements some level of understanding of human...

Systematic user errors commonly occur in the use of interactive systems. We describe a formal reusable user model implemented in higher-order logic that can be used for machine-assisted reasoning about user errors. The core of this model is a series of non-deterministic guarded temporal rules. We consider how this approach allows errors of various specific kinds to be detected by proving a single theorem about a device. We illustrate the approach using a simple case study.