A many splendoured thing ... Wolf Seufert New Scientist 22 Feb 1997
LOVE is the most insidious of emotions. The lovestruck mind careers between an illusion of la vie en rose, and obsessive fears of betrayal, like those that brought Othello to commit the horrid deed. The mood swings of the lovesick are notorious and extreme- as, I hope, you can recall. To fall in love is to fall beyond help. Those struck by Cupid's arrow are beyond reason. They quiver for a glimpse of, or a word from, their beloved and pray that they can arouse the same strange feelings in them. And if your physique is in need of some improvement, your financial security precarious and your social graces not all they might be, you will be hoping for a miracle-or perhaps a love potion. Something that will inspire, with a single swig, blind love in the person for whom you are afire. But reliable practitioners of the ancient black arts are hard to find in the average shopping mall. Those few dubious concoctions that have survived almost into the 21st century carry obligatory disclaimers, leading to the obvious conclusion that they don't work. Science will surely hold the answer? The idea of pheromones, the chemically defined sexual attractants of the animal world, come to mind. For some species, yes. But sadly, they have not evolved to the kind of sophisticated purpose that we require. Insects seem to have derived an evolution- ary advantage from pheromones, but such substances cause them to engage in indis- criminate copulation, sometimes en masse. Perhaps science should be prevented from discovering a human equivalent. Suppose, for instance, after a visit to the pharmacist, you accidentally smashed the bottle while struggling for a seat on the crowded 6.15 to the suburbs ... No, we are not dumb animals, mere slavering victims of reproductive necessity, even if we can be the hapless slaves of our emotions. Males are said to fall for beauty, while females can be swayed by a sense of humour, intellect and piles of money. Gone are antiquated biological reasons in choice of mate. For the modern Western male, a wide pelvis for giving birth is not high on the list of desired attributes in a prospective partner, while women have become providers for themselves, and are probably happy no longer being forced to shackle themselves to dull men just for their money. The problem with the love potions of old or human pheromones is that they are non- specific. The object of your affections could sip the doctored wine during a romantic evening out-and leave with the waiter or waitress. Rather, we are looking for some- thing that not only stimulates affection, but also points it in your direction. I suspect that the answer to this problem may have been around for a while.
Way back in 1976, researchers at the Sloan Kettering Cancer Institute in New York observed that mice preferred to mate with females that had a different set of one type of the recognition proteins of the immune system, the so-called major histocompatibility complex (MHC). These proteins are present in nearly all cells; they characterise the individual, recognise transplants or invading microorganisms as foreign, and mobilise the immune defences against them. The male mice in the study were lit- erally able to sniff out some expression of the distinguishing MHC markers in the females and chose their sexual partners accordingly. immunology might seem rather dull and unrelated to sexual attraction. But the immune system, which spends its life attempting to define the "self", is perfectly placed to pass on personal information to potential mates. Humans are no exception, it seems. Claus Wedekind and colleagues at the University of Bern asked female students to smell unwashed T-shirts of men unknown to them and rate them for "pleasantness" (New Scientist, Science, 6 May 1995, p 19). State-of-the-art serologic typing revealed the MHC genotype of all subjects. They conducted their investigations under scrupulously sound control conditions and cautiously eliminated anything that might falsify the score. The results, confirmed statistically, show that male body odours were considered more pleasant by women with a dissimilar set of MHCs. The really intriguing result was that if the women were on the Pill, they preferred the smell of men with a similar set of MHCs. Fascinating conclusions spring to mind which Wedekind and colleagues seemed studiously to avoid. The difference in preferences of women taking the Pill shows that hormones can influence the choice of a mate. Is, then, a couple's life perturbed when she goes on or comes off the Pill, or becomes pregnant? And more importantly for our romantic quest, could a hormone cocktail be used to manipulate sexual attraction very specifi- cally? Could the fiendish suitor or suitoress who does not get the desired romantic response spike the drink of the intended with steroids on the sly, and ensure that instant love ensues? Those gripped by dementia cupiditatis who wish to dabble in such dangerous speculations should look first at Sexual Pharmacology by Theresa Crenshaw and James Goldberg (W W Norton, 1996). If your results prove alarmingly successful, there are some cooling off recipes as well.
Wolf Seufert is at the Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
Scent of Eros:
Mysteries of Odor in Human Sexuality
James Vaughn Kohl and Robert T. Francoeur, Ph.D. Foreword by William E. Hartman and Marilyn A. Fithian 276 pages 0-8264-0677-7 $24.95 hdb + $3.00 shipping
Men Respond to the Scent of a Woman New Scientist 7 Sept 1996
IT HAS long been believed that men are unable to tell when women ovulate. But new research from Austria suggests that although men may not be aware that a woman is ovulating, they do respond physiologically with increased testosterone levels. Astrid Jutte, a researcher at the Ludwig Boltzmann Institute for Urban Ethology in Vienna, carried out tests on 106 men, divided into four groups. Three groups were asked to inhale one of three synthetically produced human copulins-fatty acids found in vaginal secretions in women at various times during the menstrual cycle. one of the copulins mimicked ovulation, one menstruation and the third another point in the cycle. The fourth group of men inhaled only water vapour. Jutte found that testosterone levels in the saliva of those men exposed to the scent of ovulation increased by half, while levels in those sniffing only water dropped by half. Levels in the two other groups increased slightly, says Jutte. Previous research has shown that although rhesus monkeys respond to ovulation by scent, in human females ovulation is "hidden" from men. One theory has suggested that hidden ovulation makes it possible for a woman to cheat on her mate if he is found to be genetically unfit.
But Jutte believes the idea that human ovulation is truly hidden has never been properly tested. "These results suggest a special kind of hidden ovulation," she says. "The effect on testosterone levels changes the picture completely." She points out that many mammals have an additional scent organ to perceive smells designed to alter their behaviour or physiology. Previous tests indicated that humans also have this organ, known as the vomeronasal. Although Jutte showed that men respond physiologically to ovulating women, she says she was unable to prove that ovulation affects their attraction to women. Alison Motiuk
VNO receptors and pheromones
If you're looking to improve your social life, maybe you should pay some attention to your smell.
LONDON - We spend a fortune eliminating body odour, but are we maldng a terrible mistake? The news from the research labs is that the right sort of body odours can trigger desire more effectively than a bottle,of costly scent. It seems that we have two sets of chemical detectors in our noses. As well as the one that responds to newly-baked bread there is another that is triggered off by the waste products produced by millions of bacteria that chomp at fat deposits on your skin. Precisely,the material you have been scrubbing off and trying to disguise. We are tallking pheromones here - chemicals, the slightest whiff of which sends most mammals and insects into a sexual frenzy. However, scientific wisdom has always held that humans are not susceptible to such crude stimulus- response mechanisms. What is more, say today's experts, we do not have the sense organ needed to respond to pheromones. Animals detect them with a special organ in the nose that is different from the one that detects ordinary smells. . Called the veromonal nasal organ (VNO) it consists of two small pits with tiny openings in their centres about a tenth of a millimetre wide. But although we develop one as a foetus, it then atrophies in nearly all adults, like the appendix or the tail, our VNO is something we can now do without. But our lofty eminence may be about to take a tumble. According to the magazine New Scientist, a group of American researchers claims to have discovered the VNO in humans, raising the possibility that we may be responding to chemi- cal messengers. Dr David Berliner of the University of Utah became interested in the potent effects of pheromones when he found that bringing out a patch of skin he was worldng on changed the whole feeling in the lab. Everyone left their test tubes and started playing cards. Together with Dr David Moran of Pennsylvania University and Dr Bruce Jafek at the University of Colorado, Dr Berliner examined subjects who virtually all had VNO pits - about lcm up the nostril. For the past few years the team has been experimenting with the human VNO and have found it responds to quite different chemicals from those that trigger off our sense of smell. And there seem to be clear gender differences - men's VNOs respond vigorously to steroids from the sldn of a female and vice versa. Not everyone is convinced. For a start, Berliner has a vested interest in our VNOS, having raised $12 million to exploit his discovery. His company is already selling "his and hers" pheromone perfumes. What's more, no one has repeated the work yet. And even Dr Berliner's team has not been able to show that nerves from the human VNO actually go into the brain. But, as he points out, there is a good reason for this: 'We know a lot about the rat's VNO, but studying the human one is hard because not many people are willing to have dyes that trace nerve cells injected into their brains, then have their heads cut off so you can take sections to see where the dyes went." But if we are not affected by pheromones, it's hard to explain why we pro- duce them all the time all over the body - in the bacteria leftovers we scrub away before a rtight out. The watery sweat comes from one set of glands (eccrine) and gets mixed with tiny amounts of fatty material from two other types of glands (sebaceous and apocrine), both found around hair follicles. It is surely significant that in puberty we sprout hair in precisely,those areas that fill with blood when we are excited, so they heat up and produce more bacteria snacks. The warmer they get, the more easily the leftovers evaporate. Dancing close and slow brings (most) men up against the apocrine and sebaceous supplies in her hair while she can nestle in to. those in his armpit. Think twice before applying that deodorant-. - GUARDIAN
New Scientist 22 Aug 98 11
MEN are not the only ones who experience a testosterone surge
after watching a pornographic film-women do too, Austrian researchers
have discovered. Their findings call into question the commonly
held view that males and females respond in different ways to
sexually explicit material, they say. Astrid Jofte and her colleagues
at the Ludwig Boltzmann Institute for Urban Ethology in Vienna
asked 10 men and 10 women to watch a 15-minute pornographic film.
The researchers took four blood samples: before the film and three
at intervals afterwards. There was a significant increase in testosterone
in both males and females after the film, JOfte said. The median
increase in men was 100 per cent, she says, and for women it was
80 per cent. Studies have shown that the more testosterone a woman
produces over the monthly cycle, the more sexually active she
tends to be, but little is known about the effects of short-term
surges in this hormone, says JOfte. "Maybe it changes her
sexual drive or her motivation for sex," she speculates.