The effect of hearing protectors on the attention demand of warning sounds

A reason often given by noise-exposed workers for not wearing their hearing protection is that it impairs their ability to hear important sounds such as acoustic warning signals. An experiment was therefore conducted to assess the possible effect of wearing hearing protection on the attention demand of a typical industrial warning sound. Inattention was created by providing uncertainty as to the time occurrence of the signal, and a separate loading task. The results indicate that neither inattention, nor the combination of inattention and the wearing of hearing protection, need necessarily impair the perception of a warning sound. The experiment therefore found no basis for the attitude that hearing protectors impair the effectiveness of warning sounds. This conclusion may not however apply to warning sounds which are not distinct from the ambient noise, those which have to be recognized amongst other discrete sounds, or to users of hearing protection with an existing noise-induced hearing loss.