The Effects of Varying Break Length on Attention and Time on Task.

Abstract

We aimed to discover how varying the length of task breaks would affect the time-on-task effect in subsequent testing periods. An important means of preventing errors and accidents caused by mental fatigue and time on task is to intersperse rest intervals within long work periods. Most studies of rest pauses to date have examined their effects in real-world tasks and settings, and their subtler effects on behavior, as measurable by laboratory paradigms, are not well understood. We studied a group of 71 participants as they completed a 1-hr auditory oddball task with two rest opportunities. Rest intervals were 1, 5, or 10 min long. Improvements in reaction time were significantly positively associated with length of the rest break. However, longer breaks were also associated with steeper decrements in performance in the subsequent task block. Across individuals, the amount of immediate improvement correlated with the extent of later decline. Our results support a resource/effort-allocation model of fatigue, whereby longer breaks bias participants toward greater effort expenditure on resumption of the task when cognitive resources may not have been fully replenished. These findings may have implications for the refinement of work-rest schedules in industries where time-on-task degradation in performance is an important concern.