The Sense of Human Scents

There are other quirkier and more provocative if preliminary findings. Both men and women appear to prefer the body odors of opposite-sex people who are physically symmetrical?that is, who have not been subject to any genetic or environmentally toxic stimuli that have caused some measure of physical deformity. Jeannette Haviland-Jones of Rutgers and Denise Chen of the Monell Chemical Senses Center in Philadelphia (a remarkable institution) have some intimation that the odor of postmenopausal women is relatively calming, and a baby's scent has scant effect on non-parents, while teenage boys generated a negative effect. If such findings turn out to be robust, the question about them is, how do they work? What is the mechanism? What is going on?

A host of other fascinating smell-facts continues to tantalize scientists and interest everyday human people. One celebrated finding was Martha McClintock's 1971 discovery that, by the end of the school year, women living together in a dormitory synchronized their menstrual cycles, which had been wholly random at the beginning. Unless, that is, they were taking the contraceptive pill, which controlled the rhythm of cycling.

This was intriguing indeed. A few years later, I and some colleagues at Rutgers and its medical school tested the impact of the contraceptive Depo-Provera on the sexual behavior of monkeys. We found that it completely extinguished what had been a vigorous response by the dominant male to his favorite females when they were not medicated. But after they had been treated, and the subcutaneous dosage wore off after three months, they evidently once again emitted the buzz that seemed to be the essential component of lively sexual monkey business. The boss male had clear sexual preferences, which medical intervention interfered with quite unequivocally.

All the evidence for why this happened pointed to a pheromone or smell-like substance that was somehow communicated between loving couples. Again, recently, from McClintock and Suma Jacob of University of Chicago, we learn that the hormone-like substance androstadienone had a discernible impact on women given it experimentally. Evidently they showed some euphoria, elation and increased sociability. They also displayed evidence of sensual body-states even though they were unaware they were sniffing the andro, which had been masked by clove oil. McClintock and Jacob cautiously and correctly observe that it is altogether unclear whether andro might be a human pheromone, with broad general impact. Nevertheless, this is another interesting finding that suggests human beings may exchange a portfolio of influential messages providing as little visible evidence of their existence as the relevant mechanisms dancing around cellphones.

Meanwhile, back at the ranch house, people are engaged in the favorite American recreational activity?planting flowers and gardens. People like gardens, which represent an effort to recapture the natural environment in which we evolved, which was a garden, not a city. The smell of autumn woods or a spring meadow is completely preferred to the smell of traffic. Virtually all the successful and luxurious perfumes and colognes are the essence of flowers. If you drive on the Riviera near Grasse or Mougins or Nice, there are literally acres of greenhouses producing nothing but flowers to be processed into taut liquids to be tapped behind your ear. Perfumes smell good because the flowers of which they are made were part of the sensory apparatus that served us for millions of years of life on savannahs, near water, around trees. Even the sea smells pleasing, and a pine forest too. There is no perfume called "The Subway at Rush Hour." You can search in vain for a Chanel product called "The Scent of Outdated Oil Refineries on a Humid Day When the Hot Air Is Still."

There is much reason to believe that things that smell bad are bad for us. As with sour and bitter taste, our evolution has provided us a rapid-fire means of consumer-testing what is in danger of intruding on our bodies. This is one reason some hospitals report that their clients feel better during their stay when the traditionally acrid and penetrating smells associated with illness are masked by particular aromas piped into the air provided to patients, and this must be part of the same naturalist syndrome that has postoperative patients recovering faster in rooms that look out at gardens rather than cement. And why blood pressure falls in natural settings?perhaps why countless people have houseplants.

Obviously there is a cavalcade of fakery and empty boasts that has been attached to what is broadly called aromatherapy but there is as well reason to treat with affection and respect human tastes in smell. Smells lure and protect us. There was an extraordinary novel called Perfume written by the German Patrick Suskind. It described an abandoned boy who was born with a consummate ability to analyze and recreate the most wonderful and repulsive of smells after he became an apprentice to perfumers. But more than that, he had no smell of his own at all. He left no signature, you couldn't know he was there from smell alone. He became a vast and unexpected success in perfumes and then in politics, and then as a tyrant.

I think he represented Hitler. Watch out for people who don't smell.