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Why do we smell so bad?

  1. Feb 17, 2008 #1
    This is something I've always asked myself: why do we find our own natural scent as a species so repulsive? I mean, think of all the completely unnatural hygienic routines we have to undergo each and every day just to not offend other people with our various odors.

    It seems like there is a logic to why things usually smell "bad":
    - a rotten apple smells bad to us, because it would cause us to be ill, so finding that apple's smell repulsive is a helpful trait we've evolved
    - poo smells bad, because it also poses various health risks, and it's helpful to feel the need to stay as far away from it as possible (flies have evolved to find that same smell attractive)

    So, I can understand why the smell of extreme filth on a human would be unattractive: rotten teeth, extreme body odor, etc. would all indicate poor health (possible infection, disease, or unwanted traits for offspring); but it seems to me we have evolved to be irrationally sensitive to bodily odors—

    For example, if I were to meet a girl that just went a week without showering and brushing her teeth, even though there is nothing technically wrong with her and logically I should find her just as appealing (ie: neglecting one's hygiene for a few days is not likely to pose a health threat... hell, even doing so for a month wouldn't; we've survived as a species for thousands of years of not showering and brushing our teeth every day*), I would still find her completely unattractive, even repulsive; even if she was incredibly attractive physically, my repulsion to the odor of someone who has neglected their hygiene for just a week (ie: the natural odor of a member of my own species) would overpower any other attractive qualities she may have.

    I'm not even sure if this qualifies as a question. Maybe it's just a general observation.

    * did people in the middle ages open-mouth kiss? because they never brushed their teeth then. gross.
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  3. Feb 17, 2008 #2

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    I think this depends on the situation. If you were dropped into the middle of a Survivor episode, and met her as a cast member, there would be explanatory reasons for the dirtiness, and you might be forgiving. On the other hand, if you met her in a normal social situation, the dirtiness might give you some general information about her undesirable habits or even her mental stability (since this is a big violation of social norms), and cause you to shy away.
    Last edited: Feb 17, 2008
  4. Feb 17, 2008 #3
    Yea in the survivor case I would understand it rationally, but it still wouldn't help much in masking the smell, and therefore I would still find her unattractive at that moment. I mean, it seems like our brains are pretty much hard-wired to find such smells repulsive.
  5. Feb 17, 2008 #4


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    Perhaps this falls better under sociology or neurosciences. I am thinking it is how we interpret this information. In older civilizations (European civilizations pre- and during middle ages, or aboriginal cultures; do we know how they perceived attractiveness/repulsion based on smell?

    We ought to consider the notion of pheramones as a component of body chemistry. In my experience, I've found body chemistry to override any pungent unwashed smell or sweat of a mate. My lady tells me, clothes that have my smell on it, are comforting when I have to be away for extended periods of time. You might also google a string like "smell, odour, attraction, repulsion", there are other forums where folks have shared their experiences. Here is a related study regarding armpit odour: (reference)
    Last edited: Feb 17, 2008
  6. Feb 17, 2008 #5
    At least for me, it depends on who the person that smeels bad is as to weather or not I'll find find the smell attractive. I mean, if the person who reeks of sweat is a woman I'm attracted to, then I don't care if she just finished running the marathon, I'd be quite turned on by all her sweat. (sorry, just being honest). Anyone else on ther other hand, I'd be quite repulsed under most social circumstances.
  7. Feb 17, 2008 #6


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    Actually, I don't think we're hard-wired to find those odors repulsive. An interesting thing about the sense of smell is that our perceptions of odors varies with context. The exact same chemical odorant can smell like vomit in one context and fresh buttered popcorn in another context. We've been raised to find body odor repulsive when we smell it as a sign of uncleanliness (lack of fitness...someone who is perhaps lazy or prone to spreading germs). But, if nobody around us ever showered, we'd likely simply become accustomed to the odor and not even notice it, or might only notice the more subtle variations that are cues to attractiveness or unattractiveness.

    As an example that might be more accessible, when most people walk onto a farm for the first time, they wrinkle up their nose at the smell of the animals and their waste. But, if you work on the farm all the time, you really stop noticing that at all. Or, I've even driven past a farm and gotten a whiff of the air and thought, "Mmm, fresh silage," while everyone else was noticing, "Eww, stinky cow manure." I'm quite accustomed to being on farms around cow manure, so unless they've just spread copious amounts out on a field as fertilizer, where nobody can help but notice it, I don't really notice that, but notice the other odors instead...I notice silage because I don't smell it as often...the cattle next to me graze on grass pasture and hay.

    I've also noticed that if a man is very attractive to me, and has just come in from working hard and is all sweaty, his odor doesn't bother me. I don't find it actually pleasant, but more of a neutral, as in it isn't repulsive, it's just like coming in smelling like engine grease if he's working on a car, or grass clippings if he was mowing the yard, just odors you can identify, but aren't really attractive or repulsive.
  8. Feb 17, 2008 #7


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    This is an interesting question. I think some of this is a social or cultural question. I have definitely noticed that some cultures have different standards of body odor acceptability than mine. But I think all cultures have some standard. It might be useful to figure out the common threads underlying the various cultural standards. Then you could study the "biological" and "cultural" components somewhat separately.

    I could see all sorts of evolutionary reasons that violating such a norm, either the cultural or biological side, should make a prospective mate less desirable.
  9. Feb 17, 2008 #8
    Maybe it would make an interesting study: how do the brains of people from different cultures/environments react to the same smells, and how a person's brain reacts to conditioning to an odor he finds offensive.

    Maybe the thread does belong in brain sciences. I was thinking about this more from an evolution standpoint, assuming we've evolved to find such smells offensive, but didn't consider the possibility that we're not hard wired that way.
  10. Feb 17, 2008 #9
    Some people lose their sense of smell (So they don't smell their clothes, themselves, etc) due to allergies and I guess things like poisioning, etc. and I've heard losing the sense of smell can be the first sign of a brain tumor or some people can have a really diminished sense of smell. Also in an attempt to smell good people can use scents that are overpowering and as a result smell bad. And you may just have a really sensitive nose so scents that don't smell overpowering to other people can smell overpowering to you. which is bad because overpowering scents=bad smell. I don't have much of a sense of smell so I just try to shower lots and get my boyfriend/mom etc to smell my clothes and stuff like that. I'm both happy and unhappy I've pretty much completely lost my sense of smell. I'm getting checked for a brain tumor just because my sense of smell is so completely gone and that's probably one of the first signs of a brain tumor? but maybe its just gone because of years of allergies and stuffed up noses it's probably possible to re-train your sense of smell though? which is kind of what I want to do.

    I don't think we would dislike the smell of each other if we all showered and wore clean clothes and non-overpowering scents
  11. Feb 17, 2008 #10
    Ive never, even at the end of a PE class, noticed BO on a girl.
  12. Feb 17, 2008 #11
    I use a ton of unscented deoderant/anti-persperant and stuff like that maybe girls pay more attention to that stuff than guys do. I think they do
    Last edited: Feb 17, 2008
  13. Feb 17, 2008 #12
    Yeah of course they do, but I'm saying before even going back to locker rooms.
  14. Feb 18, 2008 #13
    Unpleasant body odors usually are bacterial products. We sweat, the bugs feed, their metabolic products don't smell good. Fresh sweat doesn't smell so bad; it's the bacterial metabolites that reek.
  15. Feb 18, 2008 #14


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    It's a cultural thing.
    Consider Napoleon's plea to Josephine, "Home In Three Days. Don't Wash,". Compared to modern America's obsession with selling you anti-perspirants and deoderants. The ads even show you someone doing a strenous workout in a gym but first covering himself in anti-perspirant!
  16. Feb 18, 2008 #15


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    Body odour did not used to be repellant, but in recent centuries the split between well-off and destitute has widened. Body odour is now associated with lack of success.

    What I find ironic is that, in modern times, a well-tanned body is now desirable, whereas in recent centuries, a well-tanned body was associated with manual, outdoor labour. It was the pasty-milky complexion that was desirable because those who were well-off did not have to work outdoors to make a living. (Aristocrats used to actually bathe in vinegar to heighten the palour of their complexion.)
  17. Feb 18, 2008 #16


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    And fat used to be glamorous, skinny meant poor and destitute.
  18. Feb 18, 2008 #17
    I guess it is more cultural than I thought.

    Call me a snob then, but I like my girls showered :biggrin:.
  19. Feb 18, 2008 #18


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    Yup. And medieval women would rub a handkerchief, or frequently an apple, in their pits and present it to a knight heading off to war. Whatever the rest of the odour, there are pheromones present.

    And was it Ogden Nash, or Bertrand Russell, or (who the hell was it?). Anyhow, one of those famous literary types was at a social gathering and some society ***** told him, 'You smell.' He calmly responded, 'No, Madam, you smell; I stink.'
  20. Feb 18, 2008 #19


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    I have a sense of Déjà Vu about this thread.. Actually, we covered similar ground in a couple of earlier threads. this one titled No shower month, began on May 2005. Several comments on the current thread were expressed on 3 yrs ago on 'No shower' thread.. Then there was a thread about Armpit Odor beginning Sept 2004.
    Last edited: Feb 19, 2008
  21. Feb 18, 2008 #20
    two weeks?? the longest I've gone is a day. both times we had plumbing problems at home and the water wasn't working, and both times I called in sick to school and work. There's NO way I'd leave the house without a shower.

    ewwwwww, please don't tell me they ate that apple! why an apple?? who wants a sweaty apple that smells like an armpit?

    I'm so glad I live in the 21st century.
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