I don’t think that they do. Consider canine ears (the foxlike ears on dogs like shepherds): these ears are clearly horns, that are steerable, and concentrate soundwaves. My dog can move them, so as to zero in on a noise source. But human earlobes seem to be more about dissipating heat-they have tons of blood vessels in them, and they do get hot.
Do they actually cool the brain?
Dogs diddipate brain heat throgh their nose structures-do human ears serve the same function?
Human external ears do concentrate sound, if not to the same degree as a dog ear. However, one of their main functions is to enable the ability to tell where a sound is coming from; a human can tell better than a cat or dog the exact direction of a sound. The trick is all those asymmetrical convolutions; sound is slightly distorted according to what direction it comes from by those convolutions, and that lets us determine direction.
As for why; the evolutionary speculation I’ve heard is that our hearing is primarily about communication. It’s less important to be sensitive than it is to be able to tell who is saying what in a crowd. We might not have the sensitivity or frequency range of a dog, but we can stand in a crowd of talking people and hold a conversation with a specific person without losing track of who is saying what; in part because our ears can tell us where their voice is coming from.
Earlobes are the dangly thing that is attached or loose in different people. It is a very common place to pierce. It doesn’t seem to have any great function that I’m aware of.
If you mean your pinna, aka your external ear (everything you can see), then yes, it concentrates sound. That’s its primary purpose. We can’t move our ears to the extent of many animals, but it also works in sound localization. It is thought that we can learn the characteristics of sound through development that mark it as coming from the front of back. But of course we are not perfect.
Wikipedia has this picture of a Fennec under “pinna.”. I think you know why I linked to it…
I had the great pleasure of sitting through a fascinating presentation on the functions of the pinna at an Audio Engineering Society convention many, many years ago. The scientist presenting had created what was then a remarkably tiny microphone and by placing it just inside the ear canal of a range of subjects, she learned that we all have a pretty individualized response to different frequencies–sort of a hearing fingerprint. Also, one of the functions of those little wrinkles and ridges is to allow you to locate sound. If you completely block one ear (and isolate it under a very good headphone cup), close your eyes, and have someone snap his or her fingers at a constant distance from the opening of the unblocked ear, but first forward of your head, then to the side, and then behind your head, you’ll see how easy it is for you to locate where the sound is coming from. The difference in the way that noise “sounds” in different locations is due to the little ridges and canyons. Using the in-ear microphone to record the noise and analyzing it a frequency map, you can can clearly see the changes.
My significant other (now husband) brought family conversation to a dead stop the second time he met the whole gang. As we sat around the family dinner table, he announced brightly “I have a body part that AuntPam doesn’t!” As we all gaped at him he finished the explanation: “Earlobes!” And he’s right–my ears just join my head with no little dewlap of an earlobe. Probably why I’ve never had 'em pierced.
That explains something: I have a relative with a hearing aid. But despite it being very high quality, better by far than her original ears, she still has difficulty in a group setting, with many conversations going on at once – she says she can’t concentrate on one conversation, because she is hearing all the other nearby conversations too.
It may also be due to the nature of the hearing loss itself. If it is the typical primarily sensorineural hearing loss associated with aging, presbycusis, it is pretty standard, as good as newer aids are. Background noise make it very difficult and there is sometime a paradoxical hypersensitivity to non-speech and lower frequency speech sounds.