The Power of Scent

Everyone knows what it's like to be powerfully affected by a partner's scent, but physical attraction itself may literally be based on smell.

Scent-sational Smells

Debunking pheromones without losing faith in the powers of smell

Last week, I wrote a piece for Slate trashing the notion of human pheromones. Pheromones are odor signals transmitted from one member of a species that either seduce another member or alter its hormones. 

I wrote the article because I was irked by all the silly pheromone-tainted fragrances and soaps peddled to men and women as a sure-fire way to enhance your sex life. (One of them claims their perfume can "block a man's ability to judge a woman's attractiveness based on her looks alone.") 
On top of the false ads, women's magazines promote the stuff as if they have been scientifically proven to work. They haven't. In fact, not one scientific study has even proven that mammalian pheromones exist. And don't think the scientists haven't been hunting for them. 

Insects have pheromones. Say, you're a female silkworm moth. A spritz of your pheromone (in this case, the chemical bombykol) transforms a male silkworm moth into a sex slave. One whiff and he follows your scent trail until he mounts you. But it's a gigantic leap of faith (and marketing) from bugs to people.

And yet, not believing in the existence of pheromones is not to say that I do not believe in the powers of the sense of smell. Aromas influence us enormously. 

Thanks to Nobel-prize winning research that uncovered the genes that control smell, neuroscientists now have a road map to investigate how odors travel from outside to the inner recesses of the brain. Recent studies shocked the scientific community by revealing that odor neurons, unlike other brain cells, constantly renew themselves. If we could just figure out the trick, perhaps we could coax other brain cells to regenerate, revving up cognition.

What's more, a loss of smell may be the earliest sign of Alzheimer's disease or Parkinson's disease. A distorted one may signal autism or schizophrenia. What odors smell like to you may reflect your mental state. Some doctors insist these insights will lead to a day when smell tests will be part of your routine physical exam, much the way you have your eyes and hearing examined.

My olfactory quest, by comparison, was more mundane and far less noble. I'm not a believer in one-size-fits-all aromatherapy, the notion that a particular scent is guaranteed to calm every one of us. And I certainly wasn't going to invest in quack pheromone products. I wasn't even thinking aphrodisiacs. (If you really want to learn about the human pheromone hoax, pick up Dr. Richard Doty's The Great Pheromone Myth. He is also the director of the Smell and Taste Center at the University of Pennsylvania.)

I wanted to see if I could find an energizing aroma. I was hoping for some expert advice-and once I found my essence, I'd drown myself in it.

Andreas Keller, PhD, a geneticist at Rockefeller University's Laboratory of Neurogenetics and Behavior, quashed my plan from the get-go. Unlike sight or sound, you get used to smells quickly and then no longer smell them. That's why some of the most important odors to you smell like nothing. Your home. Your boyfriend. Scientists call it adaptation. No matter how much you try, you just don't smell the smell anymore.

I also visited the Monell Chemical Senses Center in Philadelphia and got some pointers from Dr. Pamela Dalton, PhD. She told me that you can train yourself to respond to smells-a technique she calls pairing, as in pairing the odor to your emotional state. The odor, itself, does not really matter because no one has ever proved that a particular odor has an inherent impact on the brain. You may have heard that lavender oil is a relaxing blend, but it's only as calming as you deem it to be.

To help her sleep better in hotel rooms, Dr. Dalton brings a vial of citrus-floral essence that she uses every night and sprinkles a few drops on her pillow to bring back the that safe, comforting feeling of home. Better yet, she buys a new fragrance every time she goes on vacation so when she returns to work, one spray puts her back in the holiday mode. Think of it as DIY aromatherapy.

So I decided that for five days in a row, after my coffee and a morning workout (the peak of my mental stamina), I'd sprinkle on peppermint oil. The goal was to see if I'd get a mental boost a week or so later with peppermint alone during my afternoon lull. Sure, my study was as unscientific as they come, riddled with bias, lacking a group for comparison (lacking a group at all) and prone to the placebo effect. Whatever.

I pepperminted myself (judiciously of course) for five days, had a few mint-free days and then spurted it on a one afternoon during my caffeine let-down. Wouldn't you know it? I felt a boost of energy and my attention was focused. Placebo? Perhaps. But while I may not believe in the idea of pheromones, I am a huge believer in the power of the placebo.

And besides, isn't the idea of acquiring a personalized odor remedy so much more fun and useful than a smell that works on your entire species? "It's a little ridiculous," said Dr. Stuart Firestein, chair of the department of biological sciences at Columbia University. "Let's just say someone sold me this pheromone so I could attract women. There is no supermodel pheromone, so I put this stuff on and I'm deluged with horny women of all sorts, and the only thing they have in common is they all have a nose. What good is that?"