Working memory load and the vigilance decrement

In this study, we examined the impact of concurrent verbal and spatial working memory demands on performance on an alpha-numeric successive target detection task. Seven hundred and forty-five participants performed a target detection task while simultaneously performing either a spatial or a verbal working memory task or they performed matched no-memory control tasks. The vigilance decrement, both an increase in target detection response times and a decrease in perceptual sensitivity A' to target stimuli over time, was exacerbated by concurrent working memory load. The spatial and verbal working memory loads both impacted vigilance performance suggesting utilization of common executive resources. Overall, these results support the view that the vigilance decrement results from high cognitive resource demands (e.g., hard work), not from cognitive under-load (e.g., boredom or mindlessness).