Eye-Tracking in a Dual-Task Design: Investigating Eye-Movements, Mental Workload, and Performance

Abstract

Currently there are conflicting opinions regarding dual-task performance. Research by Svensson, Angelborg-Thanderz, Sjoberg, and Olsson (1997) demonstrated that adding a moderately complex secondary task decreased performance on a primary task. Contradictory to this, Kathmann, Hochrein, and Uwer (1999) demonstrated primary task performance benefits with the addition of a secondary task. The study reported here further examined the effect of a secondary task on primary task performance. In this design a baseline primary task only condition was compared to primary task performance in low, medium, and high demand dual-task scenarios. The primary task in this experiment was a paddle-ball game and the secondary task consisted of horizontal addition. This study investigated performance, subjective mental workload, the number and duration of fixations, and transitions in an effort to better understand changes in eye movements as they relate to changes in demand. Results of this study showed significant decreases in performance as well as significant increases in mental workload and transitions across conditions of increasing demand. Discussion of these results illustrates the need for further investigation and considerations for the intelligent design of user interfaces.