Does Low Frequency Noise at Modarate Levels Influence Human Mental Performance?

Abstract

The aim of this study was to assess the influence of low frequency noise (LFN) at levels normally occurring in the industrial control rooms on human mental performance (attention, visual perception and logical reasoning) and subjective well-being. Subjects were 191 male volunteers categorised in terms of subjective sensitivity to noise in general. They performed standardised tests: the Signal Detection Test (test I), the Stroop Colour-Word Test (test II), and two sub-tests of the General Aptitude Test Battery, i.e. the Math Reasoning Test (test III) and the Comparing of Names Test (test IV). Three different acoustic conditions were used in the between-subjects design: the background laboratory noise of about 30 dB(A), LFN, and a broadband noise without dominant low frequency components (reference noise) at 50 dB(A). Each subject was tested only once in random-assigned exposure conditions. Generally, no significant differences in performance related to exposure conditions were noted. Some of the results from test I and test II were influenced by sensitivity to noise. However, there were no significant differences between high- and low-sensitive subjects during exposure to LFN. The annoyance of LFN and reference noise was rated higher than that of the background noise. Subjects highly-sensitive to noise reported higher annoyance due to LFN in comparison with low-sensitives. No significant differences related to noise sensitivity in annoyance assessment of background and reference noises were noted. In conclusion, no effects due to LFN on mental performance compared to background and reference noises were found.