Brief mental breaks and content-free cues may not keep you focused.

The dominant theory amongst vigilance researchers is resource theory. From this theoretical perspective the increase in lapses with time on task, the vigilance decrement, is due to the depletion of the cognitive resources necessary for the maintenance of performance. Alternative under-load theories have recently been suggested: mindlessness and goal habituation. Advocates of mindlessness theory suggest the vigilance decrement results from conscious disengagement due to task monotony. From this theoretical perspective, the inclusion of content unrelated cues should draw the participants out of their mindless state. An alternative proposal is that vigilance decrements are a result of goal habituation. From this perspective a momentary deactivation and reactivation of task goal by inserting a brief task switch in a vigilance task should eliminate the vigilance decrement. In order to examine these alternative theories, we had 498 participants perform a visual vigilance task with either the inclusion of brief task switches, content-free cues, or in comparative control conditions during the vigilance task. All experimental groups had an equivalent robust vigilance decrement measured by both a decline in perceptual sensitivity over time and an increase in response latency over time. There was, moreover, no difference in self-reported mental workload or task-unrelated thoughts across the experimental groups. Bayesian analyses resulted in substantial evidence in favour of the null hypothesis, in agreement with the expectations based on resource theory and contrary to the expectations based on either the mindlessness or goal-habituation theories.