An Update of Findings Regarding Vigilance and a Reconsideration of Underlying Mechanisms

The effects of numerous display, task, and organismic variables known to influence monitoring behaviors are reviewed, and the principal models or theories to explain such behaviors are assessed in light of the empirical findings. The current status of vigilance theories in the mid-1970s is summarized as follows: (1) Recent research, like previous research, has failed to confirm any one theory exclusively, (2) the data available continue to cast doubt on the prospect of any current theories being able to account adequately for all established vigilance phenomena, (3) the differentiation of “cortical arousal” may provide a basis for a useful advance in an arousal-theory explanation of some monitoring phenomena, especially as related to certain brain-wave activities, and (4) other factors not encompassed by any of the theories are known to affect vigilance, some of them to appreciable extents.