Commentary on Section 4 Eye Tracking in Human–Computer Interaction and Usability Research: Ready to Deliver the Promises Robert J. K. Jacob and Keith S. Karn Introduction This section considers the application of eye movements to user interfaces, both for analyzing interfaces (measuring usability) and as an actual control medium within a human–computer dialogue. The two areas have generally been reported separately; but this book seeks to tie them together. For usability analysis, the user’s eye movements while using the system are recorded and later analyzed retrospectively, but the eye movements do not affect the interface in real time. As a direct control medium, the eye movements are obtained and used in real time as an input to the user–computer dialogue. They might be the sole input, typically for disabled users or hands-busy applications, or they might be used as one of several inputs, combining with mouse, keyboard, sensors, or other devices. Interestingly, the principal challenges for both retrospective and real time eye tracking in human–computer interaction (HCI) turn out to be analogous. For retro- spective analysis, the problem is to find appropriate ways to use and interpret the data; it is not nearly as straightforward as it is with more typical task performance, speed, or error data. For real time use, the problem is to find appropriate ways to respond judiciously to eye movement input, and avoid over-responding; it is not nearly as straightforward as responding to well-defined, intentional mouse or keyboard input. We will see in this chapter how these two problems are closely related. These uses of eye tracking in HCI have been highly promising for many years, but progress in making good use of eye movements in HCI has been slow to date. We see promising research work, but we have not yet seen wide use of these approaches in practice or in the marketplace. We will describe the promises of this technology, its limitations, and the obstacles that must still be overcome. Work presented in this book and elsewhere shows that the field is indeed beginning to flourish. 1111 2 3 4 5 6 7 8 9 10 1111 2 3 4 5 6 7 8 9 20111 1 2 3 4 5 6 7 8 9 30 1 2 3 4 5 6 7 8 9 40 1 2 3 4 5111 The Mind’s Eye: Cognitive and Applied Aspects of Eye Movement Research. Hyona, Radach & Deubel (eds.) Oxford, England Copyright © 2003 by Elsevier Science BV. All rights of reproduction in any form reserved. ISBN: 0–444–51020–6