Question: how are we hear

Daniel Mietchen answered on 14 Jun 2010:

I am not sure whether this question was meant to be “How do we hear?” or “How come that humans evolved on our planet?” or yet something else. Since Derek has already given some pointers for the second option, I will add some for the first:

Sound is a form of movement that is passed on between matter in close contact. When sound traveling in air (or water) reaches our ears, it is funneled by the outer ear, then amplified by the middle ear, and converted into electrical signals by the inner ear (which also does some sorting by frequency). These electrical signals then travel (by way of nerve fibres) through the brainstem to the sound studios of the brain in which the different frequencies, their timing and intensity are being woven together (with some aid from memory) to a sound experience that can then be combined with signals from other senses (e.g. the view of a bird with its beak moving up and down), such that we can find out whether the bird was actually singing or producing alarm calls.

For a more detailed explanation of how we hear music, see this review (in particular the last section on p. 436).

Due to the complexity of the hearing process, a number of the individual steps can work differently for different people, such that we (humans) do not all hear the same, even under identical conditions.