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The Audible Web: Auditory Enhancements for Mosaic

Michael C. Albers* & Eric Bergman

Georgia Institute of Technology
Industrial & Systems Engineering
765 Ferst Drive
Atlanta, GA 30332-0205 USA
malber@chmsr.isye.gatech.edu
eric.bergman@eng.sun.com

Current Addresses:

Michael C. Albers
Georgia Institute of Technology
Industrial & Systems Engineering
765 Ferst Drive
Atlanta, GA 30332-0205 USA

Eric Bergman
SunSoft, Inc.
2550 Garcia Avenue, MTV 21-225
Mountain View, CA 94043-1100 USA

© ACM

Abstract

Interest in the World-Wide Web (WWW), a collection of hypermedia information distributed across the Internet, has exploded with the advent of Mosaic, a graphical user interface for navigating the WWW. In spite of Mosaic's popularity, studies have found usability problems in the original interface, especially with regard to feedback, terminology, and adherence to GUI guidelines [2, 4]. This paper reports on a preliminary investigation of auditory feedback as one approach to enhancing Mosaic's user interface. The Audible Web is Mosaic embedded with non-speech auditory cues intended to aid user monitoring of data transfer progress, provide feedback for user actions, and to provide content feedback to aid navigation of the WWW.

Keywords:

Auditory interface, World-Wide Web, WWW, Mosaic user interface, Mosaic, WWW browsers.

Introduction

We chose Mosaic as a test platform for auditory enhancements because it exhibits known HCI problems: users get little or no feedback about the size and content of information referenced by links, time to obtain that information, and the results of ongoing processes [2, 4]. The highly visual task of scanning through text for links suggested to us that Mosaic users could benefit from audio. By using audio rather than visual enhancements, our aim was to provide more information while shifting additional cognitive load to a different modality.

Why Use Sound?

Non-speech auditory cues can complement visual interfaces by increasing a user's sense of engagement, enhancing monitoring of background processes, and reinforcing visually represented information [3, 5]. These principles are familiar to anyone who has played a video game with and without the sound effects.

In addition, there are situations when graphical information display may be inappropriate or invasive. For ongoing processes, auditory cues can notify users about progress, completion, and errors without distracting them from their visual task.

Why These Sounds?

When possible, our choice of auditory cues was motivated by the existing literature [1, 6]. Building on Gaver's auditory icon research, everyday sounds were mapped to computer events by analogy with everyday sound-producing events [3]. Where possible, the sound of a real world event was chosen as an auditory cue (e.g., typewriter for a text file). The sounds that are not "realistic" were selected based on their subjective affordance (e.g., low heavy piano note for large files). All of the sounds used in The Audible Web are presented at low levels above background noise in an effort to inform rather than distract users.

ENHANCEMENTS PROVIDED BY SOUND

The Audible Web uses auditory cues to enhance the interaction between users and Mosaic in three ways: by aiding users' monitoring of data transfer in progress, by providing feedback for user actions, and by providing content feedback to aid navigation.

Monitor Data Transfer Progress

After users click on a hypermedia link in Mosaic, the globe icon spins and a series of technical messages are displayed at the bottom of the window. Not only are these cues obscure, they are of little use if a user's visual attention is focused elsewhere or Mosaic is iconified.

Because sound is particularly useful for monitoring time-varying processes [3, 5], The Audible Web provides auditory cues which provide progress feedback for normal data transfer, opening of external programs, and errors. While data transfer is progressing normally, users hear clicks and pops. A sliding sound indicates when an external program is opened. If there is a error, users hear the sound of breaking glass.

Figure 1. No caption.

Feedback for User Actions

Ede and Roshak [2] found that many Mosaic users were unsure if menu items they selected had performed the requested action. The Audible Web provides feedback to reinforce user actions via auditory cues for button presses, menu selections, scroll bar movements, and link selections. The aim of this auditory feedback is to confirm actions without interrupting visual scanning and to heighten user engagement with The Audible Web by making sound an expected part of the interaction.

Figure 2. No caption.

Aid Navigation through Content Feedback

Whether a hypermedia link points to an image, another document, an audio clip, or to nowhere, every text-labeled link looks the same in Mosaic. Having little information about a link, users can only activate it and ponder the questions, "What information will I get?" and "How long will this take?".

Using non-speech audio, The Audible Web provides feedback about the probable type of information at the other end of a link before the link is activated. As users move the pointer over each link, a different audio cue plays to indicate various file types (See the table below). The aim of this feedback is to help users quickly decide if links point to information of interest to them.

By pressing the right mouse button when the pointer is over a link, users get auditory feedback for proportional transfer time, file type, file size, and errors. The length of time a tick-tock of a clock is played indicates the proportional data transfer time, an auditory cue indicates the file type, and a piano note conveys the size of the file (by varying pitch with file size). If the server is down or the file is not found, the user hears the sound of breaking glass.

For example, suppose that a user in New York queries a link that points to a small text file in London. The user hears a few seconds of the tick-tock sound (indicating proportional data transfer time) followed by the sound of a typewriter (indicating a text file) and a high piano note (indicating a small file).

Figure 3. No caption.

CONCLUSION

The Audible Web is a prototype that adds auditory cues to Mosaic to aid user monitoring of data transfer in progress, provide feedback for user actions, and provide content feedback to aid navigation of the WWW.

Our informal evaluation of The Audible Web suggests that audio has special value for informing users without distracting them from a primarily visual task. It becomes possible, for example, to query a link, but to go on reading while simultaneously learning more about the size, availability, type, and content pointed to by the link.

As users of The Audible Web, we find that the constant low level audio feedback for user actions as well as link events and attributes creates a ubiquitous audio environment, in which sounds are an expected part of interactions rather than a surprise or salient special event. This preliminary experience suggests further study is needed to understand how human-computer interactions are affected by environments in which audio is truly ubiquitous.

Naturally, there are many purposes for which audio is not well suited. Users can acquire an abstract sense of file size from audio cues, for example, but if they need to know that one file is 1.2 megabytes while another is 1.4 megabytes, non-speech audio may not provide the information they need. More work is needed to determine when and where audio is an appropriate interface element.

The Audible Web prototype suggests a host of research questions about the use of audio in applications. In future research, we must validate users' understanding of auditory cues, study the effectiveness of audio for enhancing user-interface interactions, and determine users acceptance of audio cues.

Acknowledgments

We would like to thank the members of HCI, COCO, and other groups at SunSoft for their help and support during Mike's summer internship.

References

1. Ballas, J. A. (1994). Delivery of Information Through Sound. In G. Kramer (Ed.), Auditory Display: Sonification, Audification, and Auditory Interfaces (pp 79-94). Reading, MA: Addison-Wesley Publishing Company.

2. Ede, M. & Roshak, L. (1994). Quick Findings for Mosaic Usability Test. (Usability Engineering Report #94-12). Mountain View, CA: SunSoft.

3. Gaver, W. (1993). Synthesizing Auditory Icons. Proceedings of INTERCHI'93 (pp 228-235). Amsterdam: ACM.

4. Groff, J-F. & J. Descombes (1994). Untangling the Web. Proceedings of the 1st International Conference on the World-Wide Web. Geneva: http://www1.cern.ch/WWW94/PrelimProcs.html.

5. Kramer, G. (1994). An Introduction to Auditory Display. In G. Kramer (Ed.), Auditory Display: Sonification, Audification, and Auditory Interfaces (pp 1-77). Reading, MA: Addison-Wesley Publishing Company.

6. Mynatt, E. D. (in press). Designing with Auditory Icons. Proceedings of the International Conference on Auditory Display `94. Santa Fe, NM.