Vigilance is the optimal situation in which an individual receives information form the environment, processes it, and by sensorimotor coordination, transfers it to other parts of the organism. A worker's performance in industry depends to a large extent on his prevailing level of vigilance, which may be reduced by lack of stimuli or duration of continuous activity. Consequently, at places where the work does not vary or where there is little action, it must be expected that vigilance will decline fairly rapidly.