[imagesource: American Chemical Society]

Dogs are on to something with their primary sense being smell.

Although we don’t always use olfactory information to help us make decisions about our relationship with a person, a person’s scents can provide a world of biological and psychological information below the surface.

A smell can reveal the presence of diseases (apparently, one study showed cholera smells sweet and acute diabetes smells like rotten apples), and it can also tell us something about a person’s diet, too (another study found those who eat meat smell better).

Men tend to enjoy the scent of a woman when she is the most fertile, and more testosterone levels might improve the scent of a man, according to other studies.

Per BBC, Agnieszka Sorokowska, a psychologist and expert in human olfaction at the University of Wroclaw, Poland, also notes that it is possible to sniff out someone’s personality based on their choice of fragrances.

This is because we choose cosmetics that match our genetically determined odour preferences.

But most notably, it could help us choose a mate and make healthy babies if that’s where things go.

That’s because our genetics influence how we smell, and we tend to enjoy the smell of those who are a good genetic match.

In one study, women were given T-shirts worn by random men and asked to rank them by how pleasant they were.

The women put the shirts in an order similar to the pattern of Human Leukocyte Antigen (HLA) dissimilarity (putting the T-shirts worn by men with the most dissimilar HLA profile first and the most similar last):

From a genetic point of view, it is an advantage to have a child with someone who has a dissimilar HLA profile.

“If you have a partner who is genetically dissimilar in BO [body odour] and immune profile, then your children will have a better resistance to pathogens,” says Sorokowska.

Of course, the women were not consciously picking and choosing men according to smell, and had no idea that they were identifying the men (and preferred the men) with the best match in terms of immune system genetics.

So that begs the question, do we actually use this genetic information hidden in body odour to choose our partners?

Apparently, not really.

We might prefer certain smells, and therefore certain people, but we don’t always act on that part when we are choosing a partner for life:

In a study of almost 3 700 married couples, the likelihood of people ending up with an HLA-dissimilar partner was no different to chance.

But Sorokowska says that even though HLA does not influence our choices, it can influence our sexual wellbeing with a partner.

Finally, a study by Mehmet Mahmut (an olfaction and odour psychologist at Ilona Croy at the University of Dresden) found that a strangers’ BO smells stronger than married men’s BO, likely because high testosterone levels correlate with stronger BO:

We know there is an association between a reduction in testosterone and getting older, which might be due to the things going on in a married man’s life as he gets over 40 – prioritising children and things like that.

Men who are in relationships, and more so those that have had children, have lower testosterone.

So you can probably sniff out a single man, if that’s what you’re looking for.

Use your new powers wisely.

[source:bbc]