Abstract
Forty subjects monitored a 40 min. series of 10-sec. intervals containing digits (spoken at the rate of 1 per sec.), each followed by 10-sec. silence. The task was to report whether or not three consecutive and different odd digits occurred. Responses were forced. The results showed that there was no correlation between either age or temperament and the number of correct detections made. Older subjects, however, made more errors of commission, and were less able to distinguish wanted from unwanted events. The younger and introverted subjects appeared to be more cautious. The data is discussed in terms of the arousal theory of vigilance performance.