The Uncanny Psychology Behind Scent and Attraction

How genes secretly play a factor in the grand scheme of smell.

Attractiveness is in our smell.

You smell great for some, bad for others, and most don’t really care. I would later discover that there is a genetic explanation to it that transcends not taking a bath.

Several times a sibling would point out how horrible I’d smell after exercising. Since then, I’d wipe myself dry each time I finish a session.

However, one day in college, I noticed something peculiar. As I went down the campus with a friend, she suddenly stole a whiff at my pits. She exclaimed smilingly how pleasant I smelled.

This left me perplexed. How can my natural odor smell bad to a sibling, but pleasing to a friend? Perhaps the former was being brutally honest, while the latter was messing with me.

Later I’d encounter studies stating that varying genes attract people to one another through our bodily odors.

Smelling good genes

The discipline of biology has studied the breeding patterns of mice, monkeys, and even humans for quite a while already.

Female mice have been found to choose mates based on the urine smell. This happens because proteins in their urine indicate genetic information that fights off disease.

According to Dr. Craig Roberts from the University of Liverpool, we are stuck in an “evolutionary arms race between the pathogens and the vertebrate immune system”. Simply put, we constantly compete to defend ourselves from disease.

I’d often remember my biology class, thinking genes usually work in a ‘dominant-recessive’ manner. This explains why some kids get color-blindness from parents, while others don’t. However, the group of genes in charge of our immune system, called the major histocompatibility complex (MHC), work quite differently.

Our MHC ‘co-dominate’ with each other, meaning inheriting differing sets of MHC from parents will make us even stronger against diseases.

Let’s say Dig and Vick were to have babies. If Dig was strong against disease A and Vick against disease B, their babies would likely be resistant to both diseases.

This leads us back to the topic of smell and attraction. Psychology has found out that MHC-dissimilar people smell better to you compared to MHC-similar ones (eg. close relatives).

I believe this is nature’s way of stopping you from committing incest (having sex with relatives). If that’s not enough to dissuade you, the resulting babies of inbreeding are frequently victims of miscarriage and physical deformities.

Still aren’t convinced we can sniff good combinations of genes? An experiment conducted by Professor Claus and peers cleverly reveals how much we know through smell.

The Sweaty T-shirt Experiment

Female students were made to sniff six t-shirts that were worn for two days by male strangers. Afterwards, they rated each shirt’s odor in terms of intensity and sexiness.

Lo and behold, the girls were able to accurately point which shirt were MHC-similar and dissimilar through the attractiveness of the smell.

Also, women were twice as much to recall their current or ex-lover when sniffing MHC-dissimilar shirts compared to MHC-similar ones.

MHC-dissimilarity and smell may have a bigger role on our choices of mates than we’ve realized. I am still confused though why some people are attracted to incest (eg. Game of Thrones).

Partner smells good = children live good

Nature has molded our systems for survival. With the evolving strains of disease present, we need to ensure our offspring can resist.

Common ways we might smell our partners is by taking away the perfume and cologne. This should leave you a natural aroma coded by their MHC. Of course, make sure your partner has recently taken a bath.

Originally published at on March 31, 2017.

Originally published at

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