Why does your nose get used to a smell?

This is not an answer, but is it to do with that as eyes get used to darkness/light (bearable, of course) or ears get used to sound? Is there any similarity?

There’s something here from yahoo answers:
http://answers.yahoo.com/question/index?qid=20081029133048AA5aufb

Mr Wizard did a thing with this a looong time ago. He blindfolded some kids and held a cut onion to their nose. They had to raise their hands when they couldn’t smell the onion anymore. It didn’t take long for the kids to raise their hand.

I’m not sure why it happens, but it is real. And Mr Wizard ruled. R.I.P

The term for it is “smell saturation.” I don’t remember much else.

My guess is so that you can recognize new smells coming into the area for your safety. We didn’t always have smoke detectors and whatnot.

Part of it is due to habituation. This is the process where the brain starts ignoring smells/sounds that are constantly around. The logic behind this is that the brain detects the constantly repeating or pervasive item and sees it is not a threat nor really worthy of any further processing, so it is ignored so that the brain can put that processing power towards something else. This is why smells and sounds that are pervasive (the hum of an air conditioner, the smell of our shampoo) disappear. The stimulus is really still there, of course, it is simply our perception of it that is skewed.

Here’s a good example from the wikipedia article – do you commonly feel your clothing on your body? Other than things that pinch and are tight. Think of your shirt or pants.

Are we SURE the nose gets used to a smell? I can’t say that my nose gets used to the smell of run over skunk.

I don’t actively smell the shampoo smell left in my hair, but other people can smell it, same as I can smell other people’s shampoo. The nose is just another data collector, thus its information can be ignored just like any other sensory input.

This site does not explain why, but has some interesting information”

“The sense of smell is the only one of our senses that is wired directly into the brain so that the result is immediate. The brain must interpret the other senses before they can be comprehended. The olfactory nerves have been described as “brain cells outside the brain.” The olfactory bulbs lie in the upper part of the nose. These nerves are then connected directly to the limbic system.

Saturation and fading is when we are exposed to one smell for a long time. It disappears from our conscious awareness. The most obvious is the cook who cannot smell the food cooking until she leaves and comes back into the kitchen. Tiring is when we are exposed to a succession of smells within a short time. If you smell essential oils you can only clearly smell about three or four before they all start to smell similar. Sniffing coffee beans is said to help clear the nasal pallet if you are smelling quite a number of scents.”

wow! interesting! thanks marina, and everybody else too! :)

i’m not totally sure, but i’m applying the same idea of why we get used to the sense of touch over time.

in the case of touch, your body senses that something is making contact with you to alert you to the fact that you could be in danger. like, your body is letting you know that something is touching you, whether it’s a poisonous snake, or a t shirt. after a little while, your body realizes that the t-shirt is not harmful, so it disregards it so that it can pay attention to other potentially harmful environmental stimuli. so i’m totally not sure about this, but maybe it’s the same thing with smell? maybe after awhile, once your body realizes, “okay, he’s not being negatively affected by the smell of the bread” or whatever, it moves on so that if there’s a leak of some toxic gas, you’ll be able to distinguish between the two.

oh my god, i don’t even want to reread what i just wrote, i feel like i made absolutely no sense.
:p

It’s called sensory adaptation. You can probably look it up on Wiki, if they have an article, but basically, it’s been answered that the brain stops processing that which does not change. Otherwise, we’d be smelling air for the rest of our lives!

Sight is the only of the five senses that doesn’t adapt.

The eyes themselves don’t adapt, but our brains throw out information we receive from them and fill in the blind spot in each of our eyes where the nerve connects.

this may sound WAY out of book crazy, but… the same is the situation with SEX. Sex is relatively more intresting/pleasuring during the 1st few times i.e., 1st 5% of your sex life is more pleasuring than ever(with the same person ofcourse). this is because of the same “Habituation” of our skin/sexual parts to our partner which initially used to be a alien/stranger’s body. thus by confirming that no harm is onboard with the partner, our brain doesn’t respond to it in the way it used to.

BUT OFCOURSE!!... there are other harmonal rush that gives away signals like “warmth”, “comfort” etc with your partner.there is never “Habituation” in case of harmoes.