Pippin's Question Box: Why can't adults hear the "mosquito" whine?

The main reason why adults can't hear the 'mosquito' whine is because of presbycusis. This condition causes adults (people over the age of 18) to lose the ability to hear high-pitched noises, such as the 'mosquito' whine. This condition is common, and worsens by age. Some causes of presbycusis include high blood pressure, diabetes, stress, poor diet, usage of drugs,and aging. What is interesting about this though, is that this tone was created to help shop keepers to keep annoying teenagers away from loitering in front of or in their stores, while still being able to keep adults happy and unaffected. However, this has been more useful to teenager than shop keepers because most teens set it as their ring tone during school so that they can receive text messages without their teachers hearing.

Sources:

http://www.wrongdiagnosis.com/p/presbycusis/causes.htm

http://www.msnbc.msn.com/id/13274669


http://www.nidcd.nih.gov/health/hearing/presbycusis.asp