Catherine de Lange wanted to explore the limits of the human sense of smell, so she put hers to the test. Blindfolded on hands and knees, she attempted to emulate the sensory skills of a sniffer dog by trying to follow a trail of cinnamon oil. See the experiment in the video below.
Catherine was actually repeating a project in which UC Berkeley scientists tried to train people’s noses. Researchers are learning that the human ability to smell is actually far more sensitive than they’d previously realized. One study found that humans can detect some chemicals diluted in water to less that one part per billion — that’s a few drops in an Olympic-sized swimming pool.
What’s more, smell affects human mood and behavior even if people don’t consciously register what they’re smelling.
A Japanese web site dubbed the “Smell Club” has undertaken the mission of mapping the aromas of the world. Launched last month, the site has a couple hundred devoted “smellists” who are cataloging the scents they encounter. For now, you can click on map locations tagged with things like “the bad breath of cats,” “the toasty odor of cow dung,” or “freshly aired futons.” If you read Japanese, that is. It’s unclear how they’ll account for the fact that aromas change, or if they’ll make any attempt to verify the scents.
MIT researchers report they’ve finally mass produced olfactory receptor proteins — molecules that can smell. Many researchers across the world have been working on e-noses, but the MIT research is based in the biology of the human nose. Previous efforts to make large numbers of artificial receptors have failed because the protein’s structure breaks down when it’s removed from the mucus membrane. The MIT team developed a protective detergent solution that allowed mass production of the molecules. Possible applications for artificial nose technology include sniffing for disease, environmental pollutants, and bacteria.
British electronic-nose developers have found that adding a mucus layer to their e-nose improves its sniffing ability. Just like the mucus in a human nose, the synthetic mucus used on the e-nose controls the sniffing rate, thereby improving precision and accuracy, as well as length of time required for odor analysis. Some aroma identification that had been challenging for the pre-mucus e-nose, such as distinguishing milk from cream, is now being done with ease. The research team, from the University of Warwick and Leicester University, thinks the mucus-enhanced e-nose could be on sale sometime in 2009. The team is looking into health-care diagnostic uses, including for eye infections, skin diseases and urinary infections.
Until recently, there were no good tests available for measuring the ability to smell in children. Available studies were too lengthy for kids, and measured response to odors that kids hadn’t necessarily been exposed to, even if they could smell them. A new study has changed all that. Australian scientists found 16 different odors that most kids ages 5-7 can identify. The 16 odors represent 4 sections of the palate: salty, bitter, sour, and sweet. (There was no mention in the study of the fifth category umami, the savory taste for which receptors are available everywhere on the tongue.) The 16 odors represented include floral, orange, strawberry, fish, chocolate, baby powder, paint, cut grass, sour, minty, onion, Vicks Vapo-rub, spicy, antiseptic, cheese, and gasoline. Because of the study, several standard smell and taste tests are now able to diagnose the level of smell and taste function in young children.
A recent UK study found that birth control pills impact a woman’s likelihood of sniffing out a genetically compatible mate. While it’s considered best, genetically and reproductively speaking, to choose a mate whose scent (determined by genes) is different, women in the study preferred men whose scent was similar to their own. The researchers who performed the study have some interesting theories about possible problems that could result, including fertility problems and breakups after the woman goes off the pill due to the resulting loss of scent-based attraction. The pill is apparently mirroring a function that happens when women are pregnant or no longer of mating age. Given that women usually take the pill because they don’t want children, it sounds like the pill is doing its job.
Imagine a scent you’re familiar with. Now, actually go find something with that scent and sniff it. Chances are, imagining the scent caused the same reaction in your respiratory system as actually sniffing it did. This is the result of a recent study by German scientists, published in the journal Chemical Senses. They’re calling what happens in our minds when we imagine a scent “olfactory imagery.” Fifty-six people with normal olfactory function were asked, alternately, to imagine or sniff four different odors, all odors considered pleasant by most (coffee, rose, lemon and banana). A significant increase in respiratory volume and amplitude were detected with both activities, and the increase was the same. The researchers concluded that the same mechanism is operating in the respiratory system with olfactory imagery that operates with sniffing.