An ACT-R Process Model of the Signal Duration Phenomenon of Vigilance

Abstract

Performance on tasks that require sustained attention can be impacted by various factors that include: signal duration, the use of declarative memory in the task, the frequency of critical stimuli that require a response, and the event-rate of the stimuli. A viable model of the ability to maintain vigilance ought to account for these phenomena. In this paper, we focus on one of these critical factors: signal duration. For this we use results from Baker (1963), who manipulated signal duration in a clock task where the second hand moved in a continuous swipe motion. The critical stimuli were stoppages of the hand that lasted for 200, 300, 400, 600, or 800 ms. The results provided evidence for an interaction between condition and time-on-task, where performance declined at a faster rate as the signal duration decreased. In this paper, we describe an ACT-R model that uses fatigue mechanisms from Gunzelmann et al. (2009) that were proposed to account for the impact of sleep loss on sustained attention performance. The research demonstrates how those same mechanisms can be used to understand vigilance task performance. This illustrates an important foundation for predicting and tracking vigilance decrements in applied settings, and validates a mechanism that creates a theoretical link between the vigilance decrement and sleep loss.