Task interruptability and duration as measures of visual distraction.

Tasks that are easily interrupted under intermittent viewing conditions may be less distracting while driving because they allow drivers greater control over task sharing decisions. This paper investigates the reliability and sensitivity of the occlusion paradigm as a potential means of measuring task interruptability and distraction. Twenty-four participants, between the ages of 21 and 34, completed two separate experimental sessions. In one session they performed three in-vehicle tasks (a radio-tuning task and two simulated visual search tasks) under occlusion and while unoccluded. In another session, participants completed the same in-vehicle tasks while driving in a simulator, without occlusion. The tasks did not differ in terms of total task time, yet significant differences were found using the occlusion paradigm and subjective workload ratings. Task interruptability and task duration both need to be considered when assessing the suitability of tasks for time-sharing with driving.