Effect of low-frequency random noises on performance of a numeric monitoring task.

Previous findings indicate that continuous low-frequency noises at moderate sound-pressure levels do not produce decrements in vigilance performance. Such noises are commonly found in urban environments, however; and it is important to explore their effects carefully. This study employed 27 human males in a numeric monitoring task to evaluate the effects of low-frequency (11.5 to 350 Hz) noise at moderate sound-pressure levels (80 db). More numeric signals were missed during noise than during control runs. The effect was small but statistically reliable (P smaller than .033), in disagreement with previous research. The possible environmental impact of these findings is discussed.