In a world so often fetid and unfriendly, thank heavens Valentine's Day soon will flaunt the bond between the heart and the nose.
If you've never considered the connection, consult with cognitive neuroscientist Johan Lundström, who makes his money by studying how mating calls can be smelled as well as heard.
"My research is aimed toward a better understanding of the cerebral basis for chemosensory and multimodal processing," he writes, in the least amorous of terms, on the website of his employer, the Monell Chemical Senses Center in University City.
Translation: Love stinks.
Lundström will speak on "Nasal Attraction: How Your Nose Can Help You Select a Suitable Partner," Thursday at the Wagner Free Institute of Science of Philadelphia.
But first, he wants to make sure you fully appreciate the power of the nose.
"We use smell, even when we're not aware of it," he says before calling in his research assistant, Eva Alden, to help him demonstrate that point in his lab.
(It is not a traditional laboratory, as indicated by the plastic bin labeled BO Materials. "We're collecting body odor on breast-feeding pads that are sewn into the armpits of T-shirts," Lundström explains.)
For instance, no flavor is as distinct without the help of your snout. Minus the sense of smell, you might discern the basics of sweet, sour, salty, or savory. But add the olfactory sensation, and vivid flavors explode.
Alden takes a Jelly Belly jelly bean and puts it in her mouth with one hand as she pinches her nose with the other. She tastes only nondescript sweetness - until she releases her nose. "Apple!"
Experiment No. 2 moves closer to love's aroma. Lundström takes a small bottle filled with one of the 120 chemicals, found mainly in men, that constitutes body odor. Half the population has the gene that enables them to detect its scent; the other half, not so much.
Lundström waves the bottle under the nose of Alden and senior research associate Leslie J. Stein; sure enough, Alden can smell it and Stein cannot.
That means Alden has a wider pool of scents - and men - to choose from when looking for her someone special. That's a good thing in the mating game.
"We know we have reproductive success when we pick a mate who is not close to us in our gene pool," Lundström says. Optimal mating means not too much inbreeding or outbreeding, and odors are a biological signal that help us find the special someone who occupies that middle ground.
They also filter our attention. For a study published in 2009, Lundström recruited 20 women and their male partners, as well as a female and a male friend of each woman.
The more in love the woman was with her partner (a state measured through giving her reactions to statements contained in "The Passionate Love Scale"), the more aware she was of his body odor and the less aware of her male friends'. No such attention-filtering effect existed for the same-sex friend.
Rodney Campbell, 47, of Philadelphia only has a nose for his wife, Barbara. He recently hovered near the cosmetics counters at Macy's at the King of Prussia mall, shopping for her Valentine's Day gift.
"This is my wife and she's unique - there's no one else like her in the world," says Rodney, who admitted to buying Barbara a lot of perfume. "I want her to smell differently from everybody else."
The top gift candidate this year, he says, is a bottle of "pure perfume," possibly from Tiffany & Co. Odds are high that Barbara will like it.
"I think in 11 years, he only went wrong with the perfume two times."
The Campbells agree that perfumes and colognes can stir up the desire to be close. Barbara says she might catch a whiff of his cologne as they sit on the sofa, and lean on him to say, "You smell good."
They have fond memories of childhood aromas, too. Rodney remembers his mother baking pound cake and his father's Brut cologne. Barbara smiles as she recalls her mother's Jean Naté perfume.
Forough Hafezi, the counter manager for Chanel at Macy's who has been working in cosmetics for 10 years, says it's a Valentine's Day ritual for her to assist teenage boys shopping for a perfume for their "first love."
Experience tells her that, years later, both girlfriend and boyfriend will associate the scent with young romance.
Fragrances awaken memories, she says. "It brings back when you were in love."
To see Johan Lundström do experiments illustrating the power of the nose, go to philly.com/smell