Schizophrenics, depressives, migraine sufferers and very-low-weight anorexics often experience olfactory deficits or dysfunctions. One group of researchers claims that certain psychiatric disorders are so closely linked to specific olfactory deficits that smell-tests should be part of diagnostic procedures. Zinc supplements have been shown to be successful in treating some smell and taste disorders.
Although smell-identification ability increases during childhood, even newborn infants are highly sensitive to some important smells: recent research shows that newborn babies locate their mothers’ nipples by smell. In experiments, one breast of each participating mother was washed immediately after the birth. The newborn baby was then placed between the breasts. Of 30 infants, 22 spontaneously selected the unwashed breast.
The association of fragrance and emotion is not an invention of poets or perfume-makers. Our olfactory receptors are directly connected to the limbic system, the most ancient and primitive part of the brain, which is thought to be the seat of emotion. Smell sensations are relayed to the cortex, where ‘cognitive’ recognition occurs, only after the deepest parts of our brains have been stimulated. Thus, by the time we correctly name a particular scent as, for example, ‘vanilla’ , the scent has already activated the limbic system, triggering more deep-seated emotional responses.
Other studies have shown that shy, introverted people are generally more sensitive to smell than sociable extroverts. If the ‘olfactory-survival-reflex’ theory is correct, it may be that people with high smell-sensitivity become shy and novelty-avoiding because their olfactory receptors transmit more primeval danger-signals, making them feel more vulnerable. Perhaps further research will show that the key to important personality traits may be found in the little patches of olfactory receptors in our nasal passages.
In Arab countries, a person whose perfumes smell particularly pleasant may well be asked ‘who have you been visiting?’. This is because a perfuming ritual marks the end of every social meal. After the food-trays have been removed and coffee has been served, the host or hostess (men and women eat separately) will bring out the perfume box. For women, this contains four to eight bottles of perfume and an incense burner. The bottles are passed around and each guest anoints herself with the different scents on different parts of her body or clothing, using a glass applicator. Then the incense burner is passed around, allowing each guest to perfume herself with the fragrant fumes.
The potential uses of nose-machines, which essentially mimic the functions of human noses but with more precision, are endless. Perfume makers are already using them to protect their patented smells against fake-fragrance merchants, and US dockside inspectors have used a high-tech snout to resolve disputes with fishermen over the grading of their catch.
More exciting are the possible medical applications -Warwick University scientists are researching the use of electronic noses to diagnose illness by smelling patients’ breath (Chinese doctors have been doing this themselves for centuries), and have recently been awarded an EU grant to investigate the possibility of installing tiny electronic noses in phone receivers, so that patients can simply breathe into the phone and wait for a diagnosis. A similar smell-transmission device may soon allow surfers on the Internet to ‘wake up and smell the coffee’ quite literally.
Researchers are investigating the use of breath analysis to identify the stages of the female menstrual cycle: the ability of electronic noses to detect ovulation could benefit both fertility treatment and birth control.
High-tech sniffers may be used not just for breath-smelling but also to detect other subtle changes in body odor that can indicate disease conditions.
Our unique personal body-odor may also become an alternative form of identification, signalling the end of credit-card fraud, forgotten or misappropriated PIN numbers, fake ID cards, etc. The Association for Payment Clearing Services, an organisation set up to find solutions to these problems, is investigating the use of electronic noses in banks, and companies may soon be able to replace security entry systems involving cards and codes with a device that recognizes each employee’s personal odor.