Why does hearing improve with blindness?

I have heard that people who go blind start hearing better.
Is this so? If so, is this the result of some physical
change, or do the people just start paying more attention to
sounds? Or both?

I was under the impression that hearing doesn’t actually improve, but rather, since a blind person is more dependent on hearing, is more receptive/pays more attention to their hearing.

I have a theory that much of seeing and hearing is done with the mind (brain?) For example, a 4 month old baby might have perfectly functioning eyes, but lacks the cognitive capacity to process all the visual information and resolve some kinds of images.

Seeing and hearing both take a tremendous amount of processing power, so to speak. When you listen to a symphony, you can tell the violins from the oboes from the drums, and this is because your brain is doing, in effect, a huge fourier transform on a one channel input.

Anyway, I wouldn’t be surprised to learn that if your eyes go, then some of that processing power that you aren’t using could be diverted towards your ears, making you a better listener.

Now of course this is all complete speculation on my part. In any event, it’s basically a more elaborate way of saying that you pay more attention to sounds when you can’t see.

People think that deaf people see better. Actually, more deaf people on average wear glasses than hearing people.