That’s not to say humans don’t have pheromones, or that we don’t communicate things to one another via odor. Both are true, as demonstrated by a host of studies: Infants were drawn to the scent of breast pads used by their mothers over those from other women. Men who sniffed women’s tears saw their testosterone levels drop. People who smelled the sweat of skydivers, primed by the chemical odor of anxiety, could pick out images of menacing faces more accurately than those who smelled the sweat of runners. We use scent to signal love, sadness, and fear, among other things.
And, yes, we use it in mate selection. The role of smell in attraction is one that scientists and Old Spice commercials have been exploring for some time: In one study, gay men preferred the smell of sweat from other men, while straight men preferred the smell of sweat from women. In another, women favored the smell of t-shirts worn by men with more symmetrical faces, particularly when they were ovulating. And in a separate shirt-sniffing study, women preferred the scent of men whose genetic makeup was further from their own.
This last one can be explained by a collection of genes called the major histocompatability complex, or MHC, which governs our immune system. The MHC is also what determines our “odor imprint,” an olfactory signature unique to each person and caused by a collection of chemicals that we secrete throughout our bodies, most notably via our underarms. So far, though, scientists have been unable to parse the odor imprint to identify which chemicals do what. We know that we have pheromones, but isolating them is another story.
Nevertheless, the MHC is also a handy marker for who we should or shouldn’t be having children with, says Mahmood Bhutta, a U.K. otolaryngologist and author of the paper Sex and the Nose: Human Pheromonal Responses.
“Whereas it is true that humans do not have as strong a response to pheromones as some other mammals, there is some interesting research that suggests we are still more likely to choose a mate that is genetically distinct from us, and that we use smell as the means to detect this,” he says via email. “We know that human odor is genetically determined, and that humans can, for example, smell the odor of family members, or the odor of someone not related to them.”
“Smell” may be a strong verb, though, for something we aren’t exactly aware that we’re doing. With the possible exception of Jean-Baptiste Grenouille, we don’t have the olfactory capabilities to recognize what it is we’re inhaling—the facts we take from the odor imprint aren’t processed on a conscious level. We can sniff a stranger’s t-shirt and think Man, this guy smells good. We can’t sniff a stranger’s t-shirt and think Man, this guy smells super unrelated to me, even though that may be what we’re picking up.
But while scent may be a useful evolutionary tool, a smell does not a perfect match make. Body odor can steer you away from a third cousin, but no magic perfume can steer you toward someone who laughs at all your jokes and lets you have the last donut left in the box. “There is potential that just by sniffing these t-shirts, a woman can extract information, even though it might be subconscious,” Wysocki says. “But then again, if the guy’s a real dork, body odor might not overcome it.”
Thus far, neither Iverson nor Artho-Bentz has smelled their match, though both say that that the experience has left them more attuned to the body odors of any potential paramours.
“It’s made me more aware of scents,” Artho-Bentz says. “It’s not going to work out if someone doesn’t smell good.”
“I haven’t been doing too much overt smelling” on dates, Iverson says, but he’s now less concerned about the impression his own scent makes: “I now realize it’s okay to smell the way you are. Not to say don’t shower, but I think having a little stench is actually okay, because you have the pheromones going.”
“We’ll put it this way,” he adds. “I’m not going to use cologne ever again.”