HEARING aids with more than one microphone try to pick out where sounds are
coming from, to let users hear more clearly. They work by detecting tiny
differences in the times sounds arrive鈥攂ut when the mikes have to be close
enough together to fit in the ear, results are poor.
Now Andrew Mason and his colleagues from Cornell University in New York have
discovered that a tiny parasitic fly called Ormia ochracea can locate sounds as
accurately as humans, even though its ears are only half a millimetre apart
(Nature, vol 410, p 686). The fly鈥檚 ears are physically designed to amplify time
differences, letting it detect lags as small as 25 nanoseconds. The researchers
hope that hearing aids based on the fly鈥檚 ear will be just as accurate.
