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Human Sense of Smell Underestimated 278

Benjamin Long writes to note a study, by a team of neuroscientists and engineers, that demonstrated that humans can follow a scent trail — an ability that most had assumed only animals possessed. Furthermore, the study demonstrated for the first time that humans make use of differential information from the two nostrils. The researchers blindfolded college students who crawled through grass to sniff out a chocolate-scented trail. Here is the abstract of the paper in Nature Neuroscience. From the article: "The humans, however, still sniffed much more slowly than dogs, which may partially account for canines' greater efficiency at scent tracking. [A commentator] says that despite their relatively sluggish speed, the fact that subjects improved with training is noteworthy. 'I think that shows the effect of our distinctively different behavior in actually using this sense,' he says. 'The dog [has] been doing this its whole life, and humans [were] just asked to plunge in the first time they've ever done it.'"
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Human Sense of Smell Underestimated

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  • by hadhad69 ( 1003533 ) on Tuesday December 19, 2006 @02:33PM (#17302532) Homepage
    The researchers blindfolded college students who crawled through grass to sniff out a chocolate-scented trail. This just proves students will do anything for $10
  • by AssCork ( 769414 ) on Tuesday December 19, 2006 @02:35PM (#17302560)
    I was standing behind the server racks and I thought I could sqeeze off a silent fart without anyone noticing. Sadly the offending trouser bomb got caught up in the fans of a 4U Server. The cheese-scented ass gas was recirculated through every fan in the room evenly distributing its greasy essence all over the datacenter. None of my fellow technicians will speak to me since this awful and embarrassing emission.
  • by edwardpickman ( 965122 ) on Tuesday December 19, 2006 @02:36PM (#17302570)
    The researchers blindfolded college students who crawled through grass to sniff out a chocolate-scented trail.

    Most women can follow a chocolate scented trail, oddly enough the scent trail left by diamonds and currency works just as well. On the flip side most men are able to scent track women so I guess there's balance in nature.

    • That also explains why men steal money and diamonds, but not chocolate. By the time the man gets to the end of the trail, the woman he's been tracking has eaten the chocolate.
    • by Anonymous Coward on Tuesday December 19, 2006 @03:01PM (#17302982)
      Richard Feynman (famous caltech physicist) documented his observations of this in his autobiography too; where he demonstrated for friends that he could smell out recently handled books in a book case.

      Many people who suspect their spouses of affairs also observe this ability too (knowing in which rooms a guest's been in).

      This shouldn't be a surprise to anyone; and it's pretty sad that the obvious gets passed as new, novel research.
      • Many people who suspect their spouses of affairs also observe this ability too (knowing in which rooms a guest's been in).

        Maybe they can smell the perfume/cologne? It's my experience that the "other woman" (or "other man") wants to be detected in order to force a confrontation between the committed couple, and, thus, will intentionally leave clues to be found (strong perfume/cologne, condom wrapper, undergarments, etc.) After all, they have much less to lose than the one who is involved in a committed relationship. Detecting infidelity doesn't necessarily require a keen sense of smell.

  • Duh? (Score:5, Insightful)

    by Reality Master 101 ( 179095 ) <RealityMaster101 AT gmail DOT com> on Tuesday December 19, 2006 @02:36PM (#17302572) Homepage Journal

    that demonstrated that humans can follow a scent trail -- an ability that most had assumed only animals possessed.

    Err, I recently smelled something burning. I walked through my house using my nose to follow the scent trail, and locate the single light bulb in the chandelier that had a tiny piece of plastic stuck to it that was burning (from a Christmas decoration).

    How do these researchers think I performed this amazing feat? Got out my hound dog and had him sniff around?

    • Re:Duh? (Score:4, Informative)

      by Otter ( 3800 ) on Tuesday December 19, 2006 @02:51PM (#17302810) Journal
      How do these researchers think I performed this amazing feat?

      As I understand it, the prevailing idea was that you had to walk around or move your head to identify the smoke gradient, whereas these new results suggest that you can get directional information just from nostril separation, the way you determine the direction of sounds.

      • Re: (Score:3, Insightful)

        I understand the difference you are suggesting, but doubt that was what the researchers found. Even trained dogs move their heads from side to side, determining a direction to the source by comparitive scent levels. If the students had their heads immobilzed and could still indicate a direction, that would be a different matter.
    • Re:Duh? (Score:5, Interesting)

      by Rei ( 128717 ) on Tuesday December 19, 2006 @02:56PM (#17302882) Homepage
      Who would have guessed that humans were animals after all? ;)

      Most people underestimate their sense of hearing as well. Have you ever seen any of those blind people who can use echolocation to scan an area? Pretty impressive. When I first saw a video of it, I decided to experiment around. I spun around in my (then apartment) to disorient myself, with the intent of "clicking" to orient myself. However, I found something odd: I couldn't disorient myself. There was a faint electrical hum in one corner of a room on the opposite side, and that was enough that my mind automatically reoriented me, even though that sound was undoubtedly bounding off of all sorts of surfaces to get to me. Our sense of hearing provides an excellent direction-finding ability, so the only extra components for echolocation is the ability to A) get a good echo, and B) to be able to handle more complex echo returns.

      So, I went online to see what experiments were out there. Apparently, they've done experiments in which humans are blindfolded and told to walk as close to an object as possible without running into it. They vary its distance with each run. At first, people either run into it or are way off. However, with successive runs, they become quite good at avoiding collision, ending up right next to the object. However, if you muffle their footsteps and plug their ears, they lose their ability to do this. The echoes from their footsteps are enough for them to find the object.
      • by arth1 ( 260657 )

        Who would have guessed that humans were animals after all? ;)

        Except for the religious fools who won't accept the obvious, you mean?

        Yes, humans have pretty good smell, but tend to kill it by overexposure. After a few decades of highly perfumed "hygiene" products, air "fresheners", laundry dryer perfume, perfumed danglies in the car, scented candles, strong smelling food spices, incense, burning wood, tobacco, weed, medicines, well, we end up quite insensitive.
        When I was younger, a waft of coffee or bread wa

        • Re: (Score:3, Interesting)

          by martyros ( 588782 )

          Except for the religious fools who won't accept the obvious, you mean?

          When was the last time you saw an animal create art? Or music? Or contemplate quantum physics? Or do something out of moral duty? Or exhibit any signs of any sort of religion at all? If your dog, or any other animal on the planet did any of these things that humans do on a regular basis, it would make world-wide news.

          Yes, there are certainly some similarities between the biology of humans and animals. But to ignore the difference

      • Re:Duh? (Score:5, Interesting)

        by dhalgren ( 34798 ) on Tuesday December 19, 2006 @06:21PM (#17306128)
        Years ago when I was studying ju-jutsu, we got into basic blindfighting. We'd have to kneel facing our partner while blindfolded. At first, our knees would just barely be touching. Then the non-blindfolded partner would start throwing very slow punches, which the other person would have to try to block. Then we'd move slightly farther apart, and punch slightly quicker.

        At first I thought "OK, what the hell kind of bogus ninja crap is this?" And at first there were many cheeks getting tapped. But before too long, most of us found that we could in fact block the punches. Not fast ones (I moved away shortly after this so I don't know what the others achieved in the end), but it was still pretty weird. Even in a room full of rustling gis, you would still be able to get enough audio cues (and at first, tactile ones from the touching knees) to tell more or less where the hit was coming from.

        It was pretty cool. I'd love to know how far that could be taken.

    • Re:Duh? (Score:5, Funny)

      by PingSpike ( 947548 ) on Tuesday December 19, 2006 @03:19PM (#17303304)
      Your antecdote only further proves that you are in fact, a werewolf. And of course you didn't use your hound dog. You tore that poor thing apart during the last full moon.
  • I can sniff out a KFC five blocks away and my sniffer can lead me there.
  • by russotto ( 537200 ) on Tuesday December 19, 2006 @02:37PM (#17302596) Journal one knows you're a dog. Until you start bragging about your scent-tracking superiority, then you've given away the game.
  • by lashi ( 822466 ) on Tuesday December 19, 2006 @02:40PM (#17302622) Homepage
    Hmm.. I remember reading somewhere that sense of smell is first to develope, then it gets surpassed by sense of sight and eventually relegated to background.

    I, for one, can't even smell my own breath.


    say what's on your mind - online confession and send anon email at my website []

    • Hmm.. I remember reading somewhere that sense of smell is first to develope, then it gets surpassed by sense of sight and eventually relegated to background.

      I'm sure that's been carefully studied and quantified, but when you're born your eyes aren't very developed, not that you'd be capable of understanding what you see.

      My theory is that, at least with respect to dogs, their sense of smell remains well-developed and prominent for a number of reasons. They're closer to the ground. They don't use tables or
    • by Bertie ( 87778 )
      Be thankful for small mercies, eh?
    • Re: (Score:3, Interesting)

      by Idarubicin ( 579475 )

      I, for one, can't even smell my own breath.

      Well, of course you can't. That would make your sense of smell totally useless, now wouldn't it? I mean, have you smelled a dog's breath lately?

      Through a process called sensory adaptation [], your brain automatically starts to ignore persistent stimuli. Ever notic how if a room has a particular smell, you only notice right after you walk in? The perception fades after a period of exposure; something similar happens with the smell of your breath.

      If you told

      • by exp(pi*sqrt(163)) ( 613870 ) on Tuesday December 19, 2006 @04:49PM (#17304610) Journal
        OK, I'm going to have to say some disgusting stuff in the service of science.

        There's an easy experiment to demonstrate that humans have the ability to distinguish smells very finely. The point is, humans (at least the ones I know) don't mind the smell of their own farts, but can't stand the smell of others. This means that humans have the ability to distinguish between their own farts and the farts of everyone else. Now there are three obvious classes of mechanism for this:

        (1) Humans can distinguish between their own farts and every else's - ie. they can partition fart smells into self and non-self


        (2) Humans can distinguish between everyone's farts.


        (3) Various shades in between.

        Now consider hypothesis (1). This is pretty preposterous. Chemical sensors in our nose that can only distinguish fart smells into two classes, self and non-self, would be ridiculously specialised. So we're left with (2) or (3).

        Now consider (3). To the extent that you can't distinguish self from non-self, there are people's whose farts you can't distinguish from your own. In other words, (3) implies there are other people whose farts you don't mind. This is simply too disgusting to contemplate and no benevolent deity could have created a universe like this.

        So we are led to conclusion (2).

        Anyway, I think more experiments are needed. I think this is an example of low hanging fruit if someone is seeking an Ig Nobel prize.
        • Re: (Score:3, Interesting)

          by ars ( 79600 )
          Actually there is another option.

          You can absorb gasses via the digestive tract, if you have farts building up in there some of them will be aborbed, and will circulate.

          Eventually reaching the smell cells. Via the Sensory adaptation mechanisim mentioned above, you end up not being able to smell parts of your own fart, so it doesn't smell as bad to you when it's in the room.

          PS. I have nothing to back this up, I made it up myself. Is it true? Where are those Ig Nobel researchers?
  • I've heard that a dog's sense of smell is a million times better than ours, and that they can detect a scent trail 3 weeks old. I'm pretty sure that if humans could really do that, we wouldn't need dogs to do it... not to mention that dogs don't seem to mind if they sniff something gross on the way!
    • The quality of scent trails depends on many factors including temperature, moisture and the terrain. Having been pig hunting with dogs, I've seen them being able to pick up a scent trail that was days old and only an hour or so later they could not track where a pig had walked only minutes ago. The first trail was in long grass and had been left in the morning with dew on the grass. The second was in the middle of the day over open ground.
    • by sbaker ( 47485 ) * on Tuesday December 19, 2006 @02:59PM (#17302940) Homepage
      In the NPR interview with the guys who ran the study, they said that it seemed that the only limit on the speed that practiced humans could track the scent was the speed they could crawl with their noses that close to the ground. That makes sense - I mean you can't crawl along with your nose literally in the grass at any kind of speed at all. A dog is able to run at full speed with it's nose just inches from the ground - and it's eyes are placed so it can still be looking forward as it does it.

      So this may have nothing whatever to do with the sensitivity of our sense of smell and more to do with the shape of our head, neck and the length of our fore-limbs.

      We mostly evolved to use our sense of smell for detecting whether food has gone bad or not - and for that, having nostrils right above our mouths is plenty good enough.

      Dogs are evolved to track prey and find carrion - they need to be able to sniff and run at the same time.

      Dog's noses are very's incredible to see the kinds of tricks they can manage. But I wonder where that statement of "a million times more sensitive than humans" comes from - I bet it's something some journalist guessed at 100 years ago that we are all passing on as if it were the definitive answer. This study suggests to me that some simple practicing could narrow that gap considerably.

      • by khallow ( 566160 )
        There are already highly trained human noses already out there and not all dog noses have the same degree of sensitivity. My take is that bloodhounds and other breeds with extremely sensitive sense of smell are indeed at least that much more sensitive than trained human noses. I've heard of some incredible feats involving detection of odors orders of magnitude below the threshhold concentration that human smellers could achieve. It's definitely not just that they can crawl faster than we can.
        • by corbettw ( 214229 ) <{corbettw} {at} {}> on Tuesday December 19, 2006 @04:43PM (#17304502) Journal
          There are already highly trained human noses already out there

          For example, experienced sommeliers and cheesemongers probably have even more fined tuned senses of smell (at least within their areas of expertise) than most pet dogs. Not blood hounds, mind you, but especially sight hounds and working dogs. Being able to identify ten or twelve different aromas and tastes within one glass of wine is a distinct skill, and I doubt many dogs can do it.

          At least, I know mine can't. But then, he can be a mean drunk, so maybe that's the real problem.
    • by Bertie ( 87778 )
      A dog's sense of smell is a million times better? I don't believe that for a second. Wny, my dog doesn't even know a claret from a burgundy...
  • by extern_void ( 1041264 ) on Tuesday December 19, 2006 @02:41PM (#17302656)
    Maradona has proved it many times some years ago keeping track of some white dust...
  • We Smell in Stereo (Score:5, Interesting)

    by Ranger ( 1783 ) on Tuesday December 19, 2006 @02:42PM (#17302662) Homepage
    I heard about this on NPR yesterday []. The researcher said we smelled in stereo. They proved it by plugging up one nostril at a time and then attaching a device so that both nostrils could smell in mono. The test subjects took far longer to find stuff. He also said one people got attuned to smelling a trail they were limited to the speed at which they could crawl.

    Richard Feynman did a number of smell experiments with his first wife, Arlene. He would leave the room and she would handle bottles and books then he'd return and see if he could determine which ones she'd touched. He was able to find them. It's detailed in Surely Your Joking, Mr. Feynman [].

    There! And I didn't make any smelling cracks about misunderestimating or Uranus or "once you get past the smell it tastes all right".
    • Re: (Score:3, Interesting)

      by Reziac ( 43301 ) *
      I've always had a good nose, as humans go (and an extremely discerning sense of taste, which is closely related). Much better than the average cat, and a little better than the average toy dog. Not nearly as good as my gundogs, but I can still sometimes find a shot bird (or a plastic bumper), in cover, by scent alone. I can often find stuff dropped or tracked onto the floor by scent, without having to get down to floor level to do it.

      Dogs have to learn to use their scenting ability too, and the more native
    • by rdmiller3 ( 29465 ) on Tuesday December 19, 2006 @05:10PM (#17304964) Journal

      I remember reading (somewhere) a scent-related experiment which was suggested for kids. The purpose was to demonstrate that people can differentiate the odors of other individuals even though they don't consciously smell anything at all.

      The procedure went something like this:
      Distribute a freshly-cleaned T-shirt in a zip-lock bag to all participants. Groups trying this experiment should be small, less than 10 people. Each person should bathe in the evening and wear the T-shirt overnight, placing it back into the zip-lock bag in the morning (no distinctive folding or rolling, just shoved in). When everyone is back together again, the bags are gathered while a non-participant draws numbers from a hat, writing the number on the bag and recording who brought it. The number correspondence is kept secret. Bags are then passed around and participants try to guess who wore each shirt.

      The article I was reading said that you should expect "uncanny" accuracy, the difference in scent seeming like a "hunch" or a "feeling" rather than a conscious recognition.

      Now the even weirder part. A similar experiment was done where the shirt-wearers were unknown to the sniffers. The people smelling the shirts were given a set of photographs, and asked which one the shirt seemed to belong to. Apparently, they scored correctly by a significant margin.

      Now, since I'm busy I'll just leave it up to the reader (and Google, perhaps) to find the sources.

  • Easy (Score:4, Funny)

    by MyLongNickName ( 822545 ) on Tuesday December 19, 2006 @02:42PM (#17302668) Journal
    How do you think I find my way to the computer science classroom?
  • Would I rather hold a leash and follow a dog around, or put my own face in the wet muddy grass? Hmmmmmm...
  • By the end, I'm sure the participants were drooling. Did they get to eat the chocolate?
  • Stereo smell. (Score:5, Insightful)

    by sbaker ( 47485 ) * on Tuesday December 19, 2006 @02:46PM (#17302718) Homepage
    It's not evident from the slash summary - but one interesting discovery is that we actually smell in stereo - hence two nostrils.

    That comes as a surprise to me - our other stereo sense organs (eyes and ears) are placed just about as far apart on our heads as is structurally possible - but our nostrils are really close together. OK - we don't have a really great sense of smell and we don't rely on it at all - but dogs clearly do - and their nostrils are also very close together.

    You'd think we (or at least dogs) would have nostrils mounted just below our ears.

    • Re: (Score:3, Insightful)

      by ceoyoyo ( 59147 )
      It's important for us (well, dogs anyway) to be able to get our noses close to the scent trail to pick up faint scents, so our nostrils have to stick out in front. Think of a line following robot -- it's best to have two sensors, separated a little, but not by all that much.

    • Re: (Score:3, Interesting)

      by jd ( 1658 )
      My guess would be that scent travels so slowly that stereo is not obtained from time displacement but from concentration difference, and that concentration differences are better calculated by having the nostrils directional than physically displaced. Physical displacement requires much more wiring and piping, and the payoff probably isn't worth the extra cost for a sense of smell.

      I'm curious if the researchers produced CFD models of different types of nose to compare the mechanics of different nose structu

    • Re:Stereo smell. (Score:5, Interesting)

      by lawpoop ( 604919 ) on Tuesday December 19, 2006 @03:21PM (#17303328) Homepage Journal
      ... our other stereo sense organs (eyes and ears) are placed just about as far apart on our heads as is structurally possible"

      For our eyes, that's not really true. Our eyes are placed slightly apart, looking forward so that their respective fields of vision overlap each other. Then our brain calculates how far away objects are from us by noticing how much inward each eye has to rotate to hold the object in focus.

      Prey animals, like deer and cows for example, have eyes mounted on totally opposite sides of their heads, like our ears. Each of their eyes sees an almost complete separate image. Their total field of vision is almost 300 degrees. Owls are predators par excellance, and have stereoscopic ears set just below their eyes. Their entire face is bowl-shaped like a radar dish.

      So, if we evolved solely as prey animals, we probably would have eyes on the sides of our heads, near our ears. If we evolved solely as hunters, we would probably have forward facing ears that we could rotate, like cats or wild dogs. There is some debate, but some anthropologists argue that our forward-facing eyes and stereoscopic vision comes from having to navigate in trees. This is also backed up by the fact that we have 3-color vision, which you need to see ripe fruit, where as hunters like cats and dogs see in black and white. There are vegetarian, tree-dwelling monkeys that have forward-facing eyes, stereoscopic vision, and have 3-color vision*.

      It is interesting that smell, if it is truly a stereo sense, would have both nostrils so close together. Maybe that's because light and sound waves don't get mixed up as much as scents on the wind, so each input would be very different. Also, smell seems to be a short-range sense, whereas sight and sound are long-distance senses. I don't mean that prey animals don't smell things far away, but it's not as usefully accurate as long-distance hearing or vision. If you're relying on smell to tell you when things are sneaking up on you, it will probably be too late by the time you really get a good whiff. A sound or a sight really tells you where they are, and which direction you need to run in. My guess would be that the stereoscopy of smell would be useful when you are examining something up close, such as a plant or carcass.

      *By 3-color vision, I mean that we have specific receptors cell in our eyes for 3 discrete wavelengths of light -- red, green, and blue. Some birds, for instance, have four.
    • Re: (Score:3, Interesting)

      by roman_mir ( 125474 )
      Your nose, which is right about your mouth is a very important instrument, which prevents you from even trying to put certain things in your mouth that could make you sick or kill you even, so it better be above your mouth and not behind your ears.
  • by 140Mandak262Jamuna ( 970587 ) on Tuesday December 19, 2006 @02:46PM (#17302724) Journal
    Well, in Indian cuisine, especially the South Indian cuisine there is a foul smelling spice (!?) named asafoitida which is very popular. The root for asafoitida is foetid meaning foul smelling. It actually figures as a major mystery smell in a Agatha Christie story.

    When I was young I used to hate that stuff, especially because my mom would throw blocks of it in the curries without powdering them. One bite of that chunk, and you will curse everyone in sight. So enraged I was, that I once stole her entire stash of asafoitida. I wanted to throw it away in garbage, but I was young and scared and did not dare throw it all away. So I hid it in a trunk in the loft. And, yes as I said in the subject line, my mom sniffed it out and found the stash. So yes, humans can sniff out very aromatic substances. But faint traces like a dogs do [note the significant absence of the apostrophe after the s in dogs] ? I am not so sure.

    • by khallow ( 566160 )

      I'd phrase that as either "like a dog does" or "like dogs do".

      I gather the real significance is that the test subjects can figure out with a sniff whether they're on the right or left side of a scent trail. The story doesn't seem to be about finding a stationary odor or detecting faint scents.
  • Not all humans can (Score:5, Interesting)

    by Zontar_Thing_From_Ve ( 949321 ) on Tuesday December 19, 2006 @02:46PM (#17302734)
    Benjamin Long writes to note a study, by a team of neuroscientists and engineers, that demonstrated that humans can follow a scent trail

    My first job after graduating from college was working as a computer programmer at a US Air Force base. I worked in the main building for our section of the base and our colonel one day was having a VIP come by to visit him. He walked out to the main area and smelled something burning. Convinced that his canine sense of smell had saved the day and wanting to show off for his visitor, he promptly called the base fire department and demanded that they send a truck out to investigate "the burning wires smoldering within one of the walls". The base fire department dispatched a truck and the firemen investigated and told the colonel that what he smelled was burnt popcorn from the break room and there was nothing smoldering within the walls. The colonel then did the only thing that a military man who has just embarassed himself could do. He promptly banned microwave popcorn.
    • Re: (Score:3, Interesting)

      by hey! ( 33014 )
      My dad was a professional chef. A really good professional chef. Which means that unlike your colonel, he had a professionally trained sense of smell. If he was home, and you'd been out drinking or smoking pot, you were busted. You could rush from the door straight upstairs, and he'd smell it on you from his armchair, ten feet off your path.
  • Pictures (Score:2, Funny)

    by cheese-cube ( 910830 )
    The researchers blindfolded college students who crawled through grass to sniff out a chocolate-scented trail.

    Pictures pls.
    • Oh shit... another one you people with the blindfolded college student participating in a science experiment fetish. You people are sick.
  • smell (Score:5, Interesting)

    by Anonymous Coward on Tuesday December 19, 2006 @02:54PM (#17302848)
    when I quit smoking a few years back after having smoking since I was about 13 (and raised by two smokers) I recovered my sense of smell and taste (they are certainly intertwined)
    My sense's of taste and smell are so actute now - it's amazing! I can smell people smoking a few cars in front of me - peoples aftershave and perfumes are most times extreme and putrid (I believe it must be animal urine in them)
    The weirdest experience was the re-living of memories evoked through smell, that I had long forgotton. Apparently, smell is the sense most connected to memory, I literally feel younger than ever (36yrs old in reality) Now I can smell the deeper complexities within freshly cut grass that I had completely forgotton. Quit that damn cigarette - you really do get your life back (lots more money too)
  • In testing to see if humans smell in stereo the best experiment they could come up with is having people follow a piece of scented rope in the grass? All this experiment would prove is that people can smell. If you loose the sent you turn your head to the left or right and if the sent increases, you move in that direction. They went through the extra step of jamming things in people's noses and surprise, people didn't do so well with this teflon contraption hanging off their face.
  • by CherniyVolk ( 513591 ) on Tuesday December 19, 2006 @02:56PM (#17302870)

    One thing I noticed, during bootcamp was that my sense of smell became incredibly accute. While, I'll award the reader with the fact that I was a prior smoker to bootcamp, I will say that non-smokers DEFINATELY noticed the difference as well.

    While it's not likely we as a society will retort back to nature in a sense, I will say, the body naturally cleans itself and the only reason a "bum" stinks as bad as he does is in relation to all the non-natural environment surrounding him. Not only that, but we are so used to the man made scents, that natural scents tend to stand out even more.

    For example... while some city women will think a man from the country is being a sexist pig who treats women like objects... the fact is, men CAN smell women and from a considerable distance away.

    OK. Let me stress this, becuase this is when it hit me like a brick during boot camp. It was almost a "holy shit do I have a Marvel Comic superhero nose?", no I don't and you don't either. But, when at a club, a female can be practically touching you and you might smell her perfume. In the work place, a female sitting in the next cubicle might not make her presence known until she makes sufficient noise to catch your attention....

    After five weeks into boot camp, a female division walked past the barracks we were at, and walked up stairs. I would accurately judge the distance to about 50 feet away, and every single guy in the barracks literally smelled the girls. We didn't have to hear them. We didn't have to see them. We could smell them and knew they were there. The scents were distinguishable too, not just a generic feminine hormone release into the air. If two girls were in the next room, the guys three rooms down could smell two different scents.

    When I was a kid, females weren't allowed to go hunting, irregardless of what time of month or whatever they washed their bodies with. Until boot camp, I always thought it was a wives tale that women gave off that much odor... but I swear to you. Yes, if I am able to smell a female just as well as see her from 50 feet away... then a deer or buck with much better noses can certainly smell a human female from 100 yards away. A man could probably smell the presence of a female much further than 50 feet away, it's just that's the distance I know for a fact and even at 50 feet, the scent was unbelievably strong. How far away before it becomes a hint? The girl might as well have showered in perfume and stood two inches behind me.

    Nowadays, away from the lack of everyday luxuries and eminties, inhalation of cigarette smoke, car exhaust, overwhelming stench of plastics and asphalt... no, I couldn't tell you if a girl with no perfume is sitting five feet over in the next cubicle. It's somewhat sad. But, you are capable of doing it. Most people who go on long hunting trips in the wilderness know what I'm talking about. Without all this crap we deal with, this man made crap, nature gave us some pretty interesting abilities that have been long taken for granted or the use is nolonger really needed.

    The scent of the girls is what blew me away the most. So vivid, so strong so unexpected. But, I also realized that a lot of other things that might have been overlooked or not processed certainly was while in boot camp. Such as the bed of flowers outside the barracks... yeah, you can smell those things. In modern day life, much of those scents are still hitting our nose, but if they remain being processed it's either at a subconscious level or outright ignored altogether. Anyway, it doesn't surprise me that a group of college students was able to smell a trail of chocolate in the lawn. Doesn't surprise me one bit.
    • by lawpoop ( 604919 ) on Tuesday December 19, 2006 @03:32PM (#17303494) Homepage Journal
      Let me play devil's advocate -- can you be sure that a human male doesn't have as strong a scent as a human female? Maybe women in the women's barracks are able to smell a man when they are amongst only women just as well as you and the other guys are able to smell a woman. Maybe human males have specific receptors for whatever chemicals a human female secretes.
    • Re: (Score:2, Insightful)

      by sh4na ( 107124 )
      Oh please! Females can't go hunting because the animals might smell them, because you found out you can smell a woman after living exclusively with men for weeks? What do you think men smell like to women, of rosy pastel soft stuff? rofl! If anything, men leave behind stronger scents than women do. You know, all that testosterone stuff, it's a real pain. You wanna know something really interesting-like? Hunters hunt *against* the wind. How about that for shocker?

      Frankly, how you could turn your post from a
    • There are two problems with your story and the logic for hunting. First, you are naturally "tuned" to the scent of a female of your species. Other animals are not. Second, you were specifically deprived of any trace of that scent for an extended period of time. I would not be suprised that the nose works like the eyes in that a reduction of stimulus increases the sensitivity to future stimulus, at least on a temporary basis. The reason has to do with a buildup (and depletion) of the neurotransmitters, any
  • by Jethro ( 14165 ) on Tuesday December 19, 2006 @02:58PM (#17302910) Homepage
    The researchers blindfolded college students who crawled through grass to sniff out a chocolate-scented trail.

    Sure... "researchers".

    This is one of those weird Japanese game shows!
  • by multiplexo ( 27356 ) on Tuesday December 19, 2006 @02:58PM (#17302924) Journal

    Crystal Fire [] and they had an interesting anecdote about the beginnings of semi-conductor research. In the late 1930's early 1940s the scientists at Bell labs were experimenting with silicon to see if they could build rectifiers and other electronic components out of it. At the time there really wasn't any theory about how these things might have worked. Some silicon rods showed semi-conductive behavior, some didn't. Finally they found one rod that showed strong semi-conductive behavior. They couldn't figure out what it was that made this rod special until the scientists and machinist who worked on it said that when it was cut or ground it gave off the same smell as one of the old carbide lamps that were used on many automobiles until the late 1920s. One of the chemists realized that what they were smelling was trace amounts of phospine gas, which meant that the rod has phosphorous in it. This was a surprise as the levels of phosphorous in the sample were so small that they didn't show up in a spectrographic analysis, it was the noses of the scientists and machinist that gave them the clue that the proper trace impurities in silicon would enhance the semi-conductive behavior.

  • Taste == smell (Score:2, Informative)

    by lawpoop ( 604919 )
    When we talk about our sense of taste in everyday conversation, what we are really talking about is our sense of smell.

    The taste buds on our tongue have only four types of receptors: salt, sweet, sour, and bitter. Each has a specific region on the tongue -- for instance, bitter is on the back of the tongue.

    All of the other qualities of food that we normally ascribe to taste are actually olfactory stimuli. When food is in our mouth, some of it wafts back up into our nose, where our most sensitive smelling
  • Chocolate is a relatively recent invention (bred by South/Western "Mexican" Gulf coasters in the last thousand or so years). And not essential to human survival - though some menstruating women would kill me for saying so.

    I wonder what results they'd get with oils from oranges or other citrus fruits. Which humans evolved with, along with our sense of smell, and depend upon for survival (unlike most animals, we don't synthesize vitamin C).

    And I'd like to see the differential results for chocolate sniffing so
    • I'd like to see the results sorted by gender including menstrual phase for males. I mean, based upon your post, it seems like it might just be a survival instinct for the males to find chocolate for their menstrating wives...

  • Yes, but can they smell what the Rock is cookin'?
  • a team of neuroscientists and engineers, that demonstrated that humans can follow a scent trail

    This team of neuroscientists obviouly never watched my uncle navigating the house floor to unfailingly reach the turkey leftovers, or they wouldn't be losing their time doing silly experiments.

  • to the movie, "The Animal" with Rob Schneider?

    At least Colleen Haskell would be worth trying to track with your nose.
  • But a lot of it is subconscious.
    Google "human ovulation smell" or scent or whatever. (That should be relatively worksafe, as opposed to, say "sniffing panties" which is how the original research was done, AFAIK.)
    Here's a recent article [] about how men can tell when women are ovulating.
    Here's a lit review [] from 2001, discussing just how good humans are at detecting pheromones, unconsciously.
    (I can't help but wonder what 'subconscious' means in this sense: if you smell vomit and want desperately to leave the ai
  • I smell a slow news day...
  • by beadfulthings ( 975812 ) on Tuesday December 19, 2006 @06:37PM (#17306332) Journal
    While I'm not surprised that humans can track a scent, and I'm certainly not surprised that civilization may have interfered with this ability, I'm just not sure it's one of our areas of specialization. Your average garden-variety scent hound has more scent receptors, packed into a much larger area, stashed inside that world-class smeller. His entire face, including his long, floppy ears and all those wrinkles (if he has them), is intended to funnel all that scent up into his wide nostrils, where he can interpret and act on it. I've long imagined that at the dawn of time, the human/dog interaction may have gone something like this:

    Dog to Human: Wanna go get some meat?
    Human to Dog: Yeah. You run on ahead, don't forget to let me know where you are, and I'll follow along with this stick. I just figured out how to put some sharp flint on the end of it. Should do a good job of killing that gazelle or whatever it is.
    Dog to Human: AROOO!
    Later that same evening...
    Human to Dog: Get away from that! Let me hack it up with this sharp piece of flint.
    Dog to Human: Good job! If you don't mind, I'll just gorge myself on the leftovers so I can go home and regurgitate some for the wife and pups.
    Human to Dog: Yeah, I'm taking the good parts. My wife has been gathering some kind of green stuff, and she'll put it on the meat and apply fire to it. Good eating!

    No wonder humans are generally so fond of dogs. We're hunting buddies from way back.

What is research but a blind date with knowledge? -- Will Harvey