Sustained Visual Attention during Simultaneous and Successive Vigilance Tasks

A study of sustained visual attention during simultaneous and successive vigilance task paradigms is reported. 50 participants completed a simultaneous sensory vigilance task with a low event rate, and 50 different participants completed a successive sensory vigilance task with a low event rate. In the simultaneous task participants were presented with pairs of digit-like stimuli on a PC monitor display, and were asked to detect when one of the stimuli was slightly smaller than the other stimulus. In the successive task version participants were required to compare the size of the currently viewed digit pair with the previously presented stimuli, requiring use of memory to detect the target. All participants completed a variety of subjective measures of stress states before and after the vigilance task. The results indicated that the vigilance decrement was greater for sensory simultaneous than for sensory successive tasks. Practical implications of the study are discussed.