Divergent response-time patterns in vigilance decrement tasks.

Performance on tasks tends to change with time-on-task, usually for the worse. Two seemingly contradictory patterns of behavior are reported for these "vigilance decrements." Over the past 70 years, the more common vigilance decrement involves a decrease in signal detection associated with an increase in response times. In contrast, search tasks such as industrial inspection or X-ray screening produce vigilance decrements that involve a decrease in signal detection associated with a decrease in response times. Subjects respond faster with increasing time-on-task. Three experiments reported here were designed to explain these contrasting performance patterns. The results rule out task-type (search vs. nonsearch detection) and whether trials were paced versus unpaced by the computer as causes of these divergent response-time patterns. Instead, response structure-how subjects respond to the presence and absence of the critical signal-is the primary cause of this phenomenon. These results do not support traditional resource-depletion or under-stimulation theories of the vigilance decrement. Instead, I propose a dynamic-allocation resource theory in which the attention system uses various tactics to strategically disengage from tasks that provide low payoff across time-on-task. (PsycInfo Database Record (c) 2020 APA, all rights reserved).