Mike Stobbe, AP, June 15, 2006
Black adults hear better than white adults, a government study found. The study also found that women hear better than men, and that overall, hearing in the United States is about the same as it was 35 years ago, despite the advent of ear-blasting devices such as the Walkman and the iPod.
Previous research reached similar findings about racial and sex differences, but the new study by scientists with the federal National Institute for Occupational Safety and Health was the largest national sample to report such a finding, experts in acoustics said.
The racial difference may be related to melanin, a skin pigment. Some scientists believe black people’s larger amounts of melanin protect them from noise-induced hearing loss as the years go by, study researcher William Murphy said. Scientists suspect melanin plays a role in how the body removes harmful chemical compounds caused by damage to the sensitive hair cells in the inner ear.
On average, the 1,077 non-Hispanic blacks in the study could hear higher tones at 15 to 22 decibels, the study found. The 1,245 Mexican Americans could hear high-end tones at 16 to 25 decibels, on average. The 2,518 non-Hispanic whites could hear high-end tones at 21 to 32 decibels, on average, Murphy said.
Women on average were more sensitive to higher frequency tones. They could heard higher tones at 11 to 22 decibels, compared with 19 to 32 decibels for men.
Overall, the results were mostly the same as in hearing tests done from 1971 to 1975, Murphy said.