A study on a tribe of Mabaan Africans in the Sudan showed very little hearing loss due to presbycusis. Africans at the age of sixty had as good or better hearing than the average North American at the age of twenty-five. Dr. Samuel Rosen, a New York otologist under whose supervision the study was made, attributed the superior hearing ability of the Africans to their noise-free environment. The loudest sounds the Mabaan heard were the sounds of their own voices singing and shouting at tribal dances.

Schafer, Murray R, The Soundscape- Our Sonic E…, loc. 621