Abstract

Atherley, G. R. C., and Noble, W. G. (1970).Brit. J. industr. Med.,27, 260-265. Effect of ear-defenders (ear-muffs) on the localization of sound. In a laboratory study we examined the influence of ear-defenders (ear-muffs), of a type used in industry, on a localization task using the binaural (diotic) presentation of a 1 KHz pure tone under anechoic conditions. Our subjects were 15 foundry workers, none of whom had ever used hearing protection. Fourteen men made more errors of localization with the ear-defenders than without; the other man scored equally in both conditions. For the group as a whole the total number of possible responses in one or the other condition was 720; the total correct score with defenders was 360 and the equivalent score without defenders was 546. All subjects except one showed an increase in left/right errors with the defenders. Without ear-defenders the group as a whole made 13 left/right errors; with them the number rose to 113. When they were unsure, subjects tended to make rearward in preference to frontward judgements. We concluded that our findings, especially in regard to left/right errors, may be of importance from the point of view of the safety of workpeople in industry.