Beyond the Lapse Hypothesis

A second observation that cannot be explained by the lapse hypothesis is the well-documented time-on-task decrement (5,6,32,44), which refers to systematic dete- 

PVT performance in sleepy individuals frequently shows the effects of time-on-task on lapse rates at any severity of experimental sleep deprivation (e.g., see Fig. 1). Sleep deprivation can markedly worsen this fatigue effect in PVT performance, regardless of whether the elevated sleep pressure is experimentally induced (5), or through sleep disorders such as the obstructive sleep apnea syndrome (32). Thus, cognitive performance becomes more variable with both time awake and time-on-task (44). 

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