By Corin Hadley, SciTech editor
Another night, another group of strangers. The smells, the lights, the voices - your overstimulated senses. Perhaps, in a sweaty club, you pass someone you can’t help but look back at. Under the Sauvage and Alien, are there other chemicals in the air responsible for your fluster?
Pheromones are excreted in bodily fluids such as sweat, saliva, urine and genital discharge. And yet, when we smell the sweat of someone we fancy, it’s not so offensive. Perhaps our tolerance of these usually repulsive fluids in those we are attracted to is down to how agreeable the right pheromones can be.
Pheromones are responsible for a whole world of chemical communication that is mostly beyond our sensory abilities. This ability to share information within a species helps organisms survive and reproduce. They are often described as ‘sexy chemicals’, but they have also been shown to play a major role in communicating danger and identity in the animal world - think mice playing dead in the face of danger, or dogs marking their territory.
We know that in many organisms, pheromones are indicators of health and lifestyle. When dogs sniff each other’s arses upon meeting, they are actually exchanging a complex cocktail of chemicals in which information about identity, health, diet and even behavioural tendencies is encoded. Animals are also known to use pheromones as a way of expressing the contents of their genetic code, often in order to find the most biologically compatible mate.
In humans, with language skills that let us communicate complex ideas, pheromones are mostly redundant. And yet, there are some important things that nature has decided are still best smelt, not heard.
Despite not much being know about what exactly pheromones are telling us about each other, we know that they are an important part of attraction and recognition. One well documented function of human pheromones is in telling newborns which nipple to suck on. A breastfeeding woman’s nipple produces a strong, unique chemical signature that ensures that, even from birth, a child knows where its safe place is.
Even if we don’t know what we’re smelling, perhaps these kinds of chemicals are subconsciously noticed to help steer us towards a partner. It was shown by a team of researchers at Université Paris Diderot that humans prefer the smell of people whose genetic immunity differs most from their own. Offspring from such partners would have resistance to a wider range of diseases and are therefore likely to be healthier. It has also been shown that humans are able to identify partners with who they are likely to have more reproductive success based solely on smell.
The perfume industry has tried to capitalise on this idea, and despite their deeply personal and specific nature, ‘pheromones’ have found their way into many consumer goods. Some of the most famous notes in perfumes like Sauvage and Alien (ambergris, musk, lavender, civet) are in fact plant and animal pheromones, which have been chosen because they are similar to human bodily smells. But though these perfumes smell great, to call them ‘pheromones’ on a product for humans would be to ignore the deeply personal and specific nature of these chemicals. However you might try to bottle up and sell sex and attraction, there will always be a big element of it that is fundamentally individual.
Perhaps the limited research on the subject shows that even scientists, with their desire to dissect and explain everything, know they have no chance of understanding love. One thing science does highlight is how complex it is, and how many senses might be contributing to that feeling. The emergence of so much self-improvement, ‘jacked in thirty days’ content has pushed the idea of attractiveness as an absolute quantity, that can be bought or earned. Beyond the clothes, gym pass, or beauty products you buy there are biological constants, personal to you, to which only certain people will ever respond.
Featured image: Akejsandr Popov/ Upslash
How do you smell?
