Vigilance

Vigilance refers to the ability to maintain concentrated attention and readiness to respond to rare or infrequent events over prolonged periods. It is a form of sustained attention that is particularly important in safety-critical monitoring tasks, where missed detections can have severe consequences.

In psychology, vigilance is studied through tasks that require detecting signals amidst noise over long intervals. The Mackworth clock is a classic example. Performance often declines over time, a phenomenon known as the vigilance decrement, thought to reflect fatigue, mind-wandering, and limited cognitive resources. Key measures include hit rate, false alarm rate, and reaction time, often analyzed using signal detection theory.

Various factors influence vigilance. Fatigue, circadian rhythms, motivation, task monotony, workload, and sensory masking can reduce detection performance. Individual differences in baseline attention, age, sleep history, and clinical conditions may also affect vigilance.

Applications span many domains, especially air traffic control, medical monitoring, transportation, security surveillance, and industrial process control. To mitigate declines, organizations use training, explicit fatigue management, regular breaks, task variation, multimodal monitoring, decision-support systems, automation, and human factors design to reduce workload and improve signal discrimination.

Vigilance sits within the broader domain of sustained attention and arousal. It contrasts with general alertness, which is a more transient state, and with high-level vigilance that may involve strategic monitoring and risk assessment.