The effects of ambient noise on vigilance performance

The effects of continuous noise versus intermittent noise on subjects performing an audio-visual checking task were examined. It was found that intermittent noise reduced performance as predicted by the expectancy theorists. There were no differences in overall vigilance performance between male and female observers. There was a decrement in performance with time-at-work typically found in other vigilance studies. TSD (Theory of Signal Detectability) measures were relatively stable for all subjects and closely approximated the values which would be expected in a psychophysical setting. Due to the significant increase in omission errors in the last 20 minutes of the duty period, there was a corresponding increase in the subjects' response criterion.