I can hear cars coming

[slimfandango]

I can always hear cars when they arrive in my drive. It's quite strange, even with the TV on, it's just a low pitched hum, almost unidentifiable. When my folks are round, they can never ever hear it. Does your low frequency sensitivity decline with age?

[Clanad]

It's normally the high frequency ranges that deteriorate with age.  My audiologist suggests that exposure to not only loud sounds, but "percussive" type sounds, i.e., gunfire, etc., contribute greatly to the deteroration...

[Bob A Job]

The fact you can hear a car on your own drive has nothing to do with sensitivity, just recognition.

The brain learns to recognise sounds and symptoms of changes and things that affect our lives, youve just gotten used to noticing a certain sound before visitors arrive.

Its the same as cats or dogs recognising the sound of a certain cupboard door opening before feeding time and running for food.

Your folks hearing may have declined a little but if they moved in with you after a while they would notice it too. 

[Gevs1966]

I disagree with Bob A Job.  I live in a house with three other people and can always "sense" when there is a car outside my house whether I am expecting visitors or not and even with all external and internal doors closed and the tv on etc. However nobody else in the house can do the same thing and they are always amazed when I say that a car has just pulled up especially when we are not expecting anyone.

I think it is just a case of sensitive hearing to different frequencies of noise otherwise we would all be able to do it.

Bob A Job is talking about Pavlovs association theory when he mentions the cats and dogs (I'm sure you could find it if you did a bit of googling) but I don't think that this is really applicable with this question. Eg I can hear a car when I'm not expecting visitors or if I hear a car I don't automaticaly expect the door bell to ring but it doesn't mean I can't hear it

[slimfandango]

woo, this has got cool. It might be both?

As far as I know, there are cells in the ear which tune the auditory system in an active way, so combined with recognition, they could pick up certain types of sound pattern and then tune for the best fit to pick it up?

Thanks for your input guys, keep em coming.

[Bob A Job]

Experiments have proven that we react to sounds that the human ear cannot hear. We feel them but do not hear them.

Every persons audible range varys incredibly (ever been to Karaoke)

Based on the evidence you gave (folks not noticing, but you did) I still stick with the recognition theory. Its the most likely answer.

[landie]

One thing that pleases me is that, at least, you shouldn't get run down. Your faculties must be in better nick than mine. Eh? who's that. :-)

[QmunkE]

Either my dog can associate a car arriving between a certain time with my mum arriving home, or he can tell her engine noise apart from all other cars. Does anyone else find this odd, or can all dogs do this? He always leaps up before she is even nearly finished parking, and there is no line of sight between him and the road which the car has to travel round.

[slimfandango]

landie please speak up, I can't make you out.

[landie]

''Min! Min! There's a knockin' at the door.''

''Speak up Henry, there's a knockin' at the door.''