THE EFFECTS OF HIGH INTENSITY NOISE ON HUMAN PERFORMANCE
Final rept. Oct 1966-Jan 1967
AIR FORCE AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OH
Pagination or Media Count:
Four experiments were conducted on the effects of broadband, high intensity noise on human performance. In two experiments the subjects performance was measured on a Discrimination Task, based primarily upon visual discrimination and short term memory, and in the other two experiments performance was measured on a Hand-Tool Dexterity Test. Four different noise exposure conditions were used in each experiment control 70 dB, 120 dB, 130 dB, and 140 dB re 0.0002 dynesq cm. In one experiment using the Discrimination Task, the subjects wore earplugs, and in the other, subjects wore earplugs and an earmuff with one earcup to produce an asymmetrical noise exposure at the ears. These two types of ear protectors were worn also by the subjects in the two experiments using the Hand-Tool Dexterity Task. Decrements on the Discrimination Task were obtained at the two highest noise intensities for the asymmetrical exposure and no decrements were obtained for any symmetrical exposure. With the Hand-Tool Dexterity Test, significant decrements were obtained at the noise levels of 130 dB and 140 dB with symmetrical exposure, and at 140 dB with the asymmetrical exposure. The difference in performance between the two groups was due to a different initial level of ability on the task rather than due to symmetrical versus asymmetrical exposure conditions. The results indicate that asymmetrical exposure had a greater detrimental effect on the Discrimination Task than the symmetrical exposure, while there was no differential effect on the Hand-Tool Dexterity Test. These results are discussed as a possible effect of the action of high intensity noise on the vestibular system.
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