The hunt for usability: tracking eye movements

Abstract

Usability testing methods have not changed significantly since the origins of the practice. Usability studies typically address human performance at a readily observable task-level, including measures like time to complete a task, percentage of participants succeeding, type and number of errors, and subjective ratings of ease of use [3]. Certain types of questions are difficult to answer efficiently with these techniques. Imagine, for example, that we observe users spending longer than expected looking at a particular dialog of a software application or web page without making the appropriate selection to complete the task. Participants often have difficulty reporting their behavior and the experimenter is clueless about what went wrong. Is it because the user is overlooking the control? Is the user distracted by another element in the interface -- perhaps an animated graphic? Is the user seeing the control, but failing to comprehend its meaning? Different answers to these questions would clearly lead to different recommendations. If overlooking the control is a problem, increasing its salience is appropriate. If confusion of the control's function is a problem, changing the graphic or text label may be appropriate. If distraction is a problem, decreasing the salience of other stimuli may help. Without answers to these questions, design recommendations have to be implemented by trial and error. Recording the fixation pattern of the participant's eyes can offer additional information to help answer these questions. While this concept is not new, it has been confined primarily to military aircraft cockpit issues [2,4]. Only recently has eye tracking technology advanced to make it practical in the broader usability community. Usability studies of human-computer systems that have included eye tracking, e.g., [1] are beginning to show benefits of these techniques. However, important challenges remain.