Arousal and Vigilance: Still Vital at Fifty

Abstract

Norman Mackworth (1950) demonstrated that amphetamine reduces vigilance decrement. Fifty years on, arousing agents are recognised as important influences on vigilance, but various shortcomings of traditional arousal theories have become apparent. Studies of self-report energetic arousal and vigilance confirm that arousal is a vital component of vigilance research, although arousal effects are contingent upon task demands and other moderating factors. Facilitative effects of arousal on perceptual sensitivity can be accommodated within attentional resource theory. However, it remains unclear whether arousal indexes some basic neural or cognitive capacity, or whether arousal influences ‘functional resources’ rather than basic capacity. Arousal, and other subjective state variables, may be related to effort-regulation strategy or to distraction from internal cognitions and fatigue symptoms. A sound understanding of arousal effects on vigilance is essential for developing practical countermeasures.