Why are we so sensitive to bodily odors?

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SUMMARY

The discussion centers on the evolutionary and cultural perceptions of bodily odors, particularly why humans find their own natural scents repulsive. Participants argue that this aversion is rooted in evolutionary traits that help avoid health risks associated with foul smells, such as those from decay or waste. The conversation also highlights the role of context in odor perception, suggesting that familiarity and cultural norms significantly influence how body odor is perceived. Additionally, the impact of pheromones and individual chemistry on attraction is explored, indicating that attraction can sometimes override negative perceptions of odor.

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  • Understanding of evolutionary biology and natural selection
  • Familiarity with cultural anthropology and social norms
  • Basic knowledge of human pheromones and their effects on attraction
  • Awareness of the psychological aspects of smell perception
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  • Research the role of pheromones in human attraction and mate selection
  • Explore cultural differences in the perception of body odor
  • Investigate the psychological effects of smell on human behavior
  • Study the evolutionary significance of aversive odors in humans
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Individuals interested in psychology, anthropology, and evolutionary biology, as well as those studying human attraction and social behaviors related to hygiene and body odor.

  • #31
Perhaps it's because old cats don't have much to smile about.
 
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  • #32
chemisttree said:
Perhaps it's because old cats don't have much to smell about.
Corrected.
 
  • #33
JonMoulton said:
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.

Correct. This is the response that better answers the question. Your body doesn't by itself stink. It's the bacteria that flock to the moisture on your body that stinks. And because many bacteria are not kind to us, we have an adverse response to this. The fact that people used to go months without bathing and it did not stop them from social and sexual activity may mean that we only now have so many [smelly] bacteria. Sweat that has just come off of you and has not yet had contact with the smelly bacteria has no noticeable smell.
As far as feces and flatulence smelling, this is primarily due to what we eat. I imagine things you eat which cause an excessive amount of methane byproduct will give you smellier farts, because methane by itself stinks.
 
  • #34
lilythmagebor said:
methane by itself stinks.
Actually http://scifun.chem.wisc.edu/chemweek/methane/methane.html" is an odourless gas. Perhaps you are thinking of natural
gas of which methane is a large component. In that case a sulphurous
component (e.g. http://en.wikipedia.org/wiki/Methanethiol" ) is added, which gives its characteristic scent.
 
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  • #35
Don't forget 3-methylindole, AKA skatole. That's the pure stuff.
 
  • #36
Actually, having lived and worked in the bush for ten and twenty day stints, I know that after about a week, you do not smell anymore. I believe this is because the bacteria and natural oils on our bodies get into balance. Your hair doesn't look or smell dirty. Your face isn't oily. It's quite interesting.

Also, diet has a huge impact on a person's smell. Often with our very acidic diets today, our bodies smell more. I have gone on long juice cleanses to 'reset' my body's systems and clean out my digestive tract. The body stinks badly after three to five days (regardless of how many times you brush your teeth or shower) and then you just don't smell anymore--no coating on your tongue, no need for deodorant. Cool hey?
 
  • #37
biophilia23 said:
Actually, having lived and worked in the bush for ten and twenty day stints, I know that after about a week, you do not smell anymore. I believe this is because the bacteria and natural oils on our bodies get into balance. Your hair doesn't look or smell dirty. Your face isn't oily. It's quite interesting.
You still stink, you just get used to it so you don't notice.

Frequent washing actually stimulates oil production, the longer you go without washing, the less oil you produce.
 
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  • #38
Evo said:
You still stink, you just get used to it so you don't notice.

Frequesnt washing actually stimulates oil production, the longer you go without washing, the less oil you produce.

So if you and a group of people you live around smell for a long period of time, no one notices anymore?
 
  • #39
Drakkith said:
So if you and a group of people you live around smell for a long period of time, no one notices anymore?
You get used to it, as long as it's not changed. That's why people that live in stinky houses don't realize how bad the house and everyone and everything in it smells.
 
  • #40
If you somehow sterilize your skin with maybe rubbing alcohol and then don't bathe (in a sterile bubble to avoid bacteria) would you avoid BO?
 
  • #41
Antiphon said:
If you somehow sterilize your skin with maybe rubbing alcohol and then don't bathe (in a sterile bubble to avoid bacteria) would you avoid BO?
Since rubbing alcohol won't kill all external bacteria, and under the surface we have more bacteria in glands, mouth, etc... my opinion is no.
 
  • #42
Antiphon said:
If you somehow sterilize your skin with maybe rubbing alcohol and then don't bathe (in a sterile bubble to avoid bacteria) would you avoid BO?

And there's bacteria on everything you touch including the air you exist in. If you wipe out bacterial cultures on your body, you provide a very fertile virgin soil in which all sorts of hazardous things can take over.

To be clear: the non-harmful bacteria on your skin provide hefty competition against the invasion of more harmful types that would be happy to feed on your skin waste products.

This can be very bad. It happens in the stomach and colon, when harmless or even beneficial bacteria get purged, and some very nasty bugs can get a foothold, making you very sick and possibly dead.
 
  • #43
Antiphon said:
If you somehow sterilize your skin with maybe rubbing alcohol and then don't bathe (in a sterile bubble to avoid bacteria) would you avoid BO?
Skin flora is a necessary component of your body and provides not only protection in the form of competition with harmful bacteria but also stimulates your immune system. The latter is paramount, being too clean especially in childhood is hypothesised as causing allergic diseases in later life.
 
  • #44
Have you ever gone hiking-climbing with a member of the opposite sex? You're going to both get a bit fragrant with the exertion. That should not be a problem, if you are a normal person. In fact, you might find a new obsession.
 
  • #45
Love is in the air, at least it smells like it. :smile:
 

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