Characteristics of sustaining attention in a gradual-onset continuous performance task.

Continuous performance tasks are frequently associated with a vigilance decrement, particularly when target events are rare and after prolonged time on task. Here we characterized the time course of a performance decrement that happens more rapidly. Using the gradual-onset continuous performance task (the gradCPT), we presented participants with a long sequence of scenes that gradually faded in and out. Participants pressed a button as soon as they detected scenes in one category and ignored scenes in another category. We manipulated the novelty of stimuli, required response rate, and the prevalence rate of the target stimuli. Performance sensitivity declined moderately within and across three 8-min-long blocks. Contrary to mindlessness accounts of vigilance decrement, the decline was not restricted to situations when target events were rare and the stimuli were repetitive. High motor response rates substantially impaired overall sensitivity and moderately increased performance decrement. Performance in the gradCPT did not correlate with individual differences in mindfulness, attentional lapses, media multitasking, or complex working memory span. The rapid and pervasively observed decline in performance is consistent with attentional resource theories of vigilance decrement.