Lying in bed, having just woken up I ask my partner what he thinks of smell and attraction and how I should write about it in my blog this week. Morning breath rampant, bodily odour clinging to the walls, we discuss the topic. I try to figure out the subtle nuances of his scent and what it is about it that I like so much. We talk about perfumes, animals and ex’s, you know, all the usual things that come up while on the subject, I guess it wasn’t really until later that I realised that I’d been muffledly talking to him for a solid half hour with my head face down in his arm pit.
A fling of mine once had a scent so sweet, at night it was intoxicating, but by morning the hangodour was immensely apparent. I took that as a metaphor for him not being a good match for me. Sugar is a sometimes food I told myself.
Another brief conjunction was with a businessman who swept me off my feet faster than I could ask to be put down. Soon, I inevitably came to my senses about the entire situation, but this was long after my nose had. Slowly, what was originally unapparent became blatantly obvious; this guy did not smell good. His odour became unbearably pungent. A smell that collects at the back of your throat and tugs on your tonsils harder than a bulimic ballerina, triggering an almighty gag reflex. A sensation I can still feel when recollecting the scent.
I’m unsure whether my mind helped concoct my disgust for the smell as a mental kill switch or whether my mind had just tricked me about what was there the whole time. Either way it was clear that it couldn’t go on any longer.
I’ve been judging my partners rather harshly on their smell and it seems that I’m not alone. Human and other mammal relatives have been doing it for eons. And the reason for it is that we are subconsciously looking for a genetically different partner so that our offspring will have the greatest chance of survival. Think of it like dogs, have you ever wondered why your off kilter auntie’s little wirey haired, scruffy looking Frankenstein’s monster of a dog seems to have lived since the dark ages and shows no signs of stopping any time soon? That’s because they’re not pure bred like any other dog breeds. The purity of which leads to exposed (in the genetic sense) harmful traits that would have otherwise disappeared if not mated with their cousin (cousin being a courteous under exaggeration).
You might have heard of the sweaty t-shirt experiment. An important study in the field of sexual attraction. In 1995, Swiss biologist Claus Wedekind conducted an experiment where women smelled T-shirts worn by different men, for several days, and picked the ones they were most sexually attracted to. The findings showed that the t-shirts that the women chose, as smelling the best, turned out to have the most dissimilar major histocompatibility complex, or MHC, for short.
MHC is what controls our immune system. It is responsible for signalling to an immune cell that an antigen has invaded and taken over the cell. Though MHC cannot tell the difference between a virus and a new liver, it instead has the ability to distinguish “self” from “not-self”. MHC genes inherited from both of your parents make up your bodies’ ‘password’ that every cell has to know if it wants to be allowed to stay. It’s also what ‘trains’ your body’s security guards (helper T cells) on how to throw out intruders, and each person’s body guards are better at different evictions.
Having a huge differentiation between MHC genes in a population means that if a deadly virus were to spread over the whole world, at least some of the population should have the right genes to be able to combat it. We tend to be drawn to people whose MHC compositions are different from ours so that the immune system of our offspring covers as many diseases as possible.
In addition to helping us find a partner, our sense of smell helps us maintain the connection we establish with that person, too.
Another study suggests that when a woman is not in love, she’s pretty good at recognizing the unique scents of her boyfriend, her male friends and her female friends.
But when she is in love, her ability to identify her male friends’ unique smells decreases.
The more attached she feels to her partner, the less she’s able to identify the smells of other men, who might be considered other suitors with whom to cheat or to date down the line if she and her boyfriend break up.
Our sense of smell literally prevents us from sniffing out alternate partners while we’re dating someone else to protect the monogamy of our relationship.
So, if you’re thinking about cheating, you might want to try sniffing your partner again.
But, interestingly enough, make sure you get right up in there. In a last ditch effort to explain why my face was so comfortable resting in my boyfriend’s armpit, I want to say that odour molecules we exude from our skin (most significantly from our under arms) completely change when exposed to air. So while armpit huffing might be on the cards, I draw my line at appreciating his dirty gym shorts.
Wedekind, Claus, Seebeck, Thomas, Bettens, Florence, and Paepke, Alexander J. (1995). “MHC-Dependent Preferences in Humans.” Proceedings of the Royal Society of London 260: 245-49
Miller, R. S. (1997). Inattentive and contented: Relationship commitment and attention to alternatives. Journal of Personality and Social Psychology, 73, 758-766.
Lundström, J. N., & Jones-Gotman, M. (2009) Romantic love modulates women’s identification of men’s body odors. Hormones and Behavior, 55, 280-284.
Meigs, R. A. (1971) Enzymatic Aromatization of Steroids : EFFECTS OF OXYGEN AND CARBON MONOXIDE ON THE INTERMEDIATE STEPS OF ESTROGEN BIOSYNTHESIS. The Journal of Biological Chemistry 246, 83-87.