Effects of Perceptual Salience and Task Load on Executive Vigilance: Independent and Interacting Effects Without Modulation of the Vigilance Decrement

Objective To examine the independent and interacting effects of perceptual salience and task load on executive vigilance performance, as well as whether these factors modulate the vigilance decrement over time. Background Hits in vigilance tasks typically decline with time-on-task. This decrement is explained by the resource depletion of attentional resources (overload model) or to disengagement caused by task-unrelated thoughts (underload model). Previous research manipulated salience or task load separately, yielding inconsistent findings. Moreover, few studies have examined both factors simultaneously while holding other task parameters constant. Method Two pre-registered studies and a pooled data analysis were conducted using the ANTI-Vea task, which assesses attention and vigilance components. In Study 1 ( N = 84), perceptual salience of the target stimulus was manipulated between participants. In Study 2 ( N = 45), perceptual salience and task load were orthogonally manipulated within participants. Study 3 re-analyzed combined data ( N = 238) from Studies 1 and 2 together with data from previous research. Results Executive vigilance showed significant effects of perceptual salience and task load, with larger overall accuracy observed for the most salient targets and under moderate task load (dual-task condition). In signal detection measures, A ′ was largest for the most salient targets, whereas moderate task load was associated with a less conservative response bias ( B ″). However, neither variable modulated the observed vigilance decrement over time. Conclusion Perceptual salience and task load affect overall executive vigilance but do not modulate its decrement over time-on-task. Application Findings may inform the design of tasks and systems that optimize vigilance by promoting an optimal balance of task demands, by considering perceptual salience and task load to minimize failures and reduce the risk of vigilance decrement-related accidents.