What is it that you find most attractive in a person? Their eyes? Their hair? Maybe their teeth?

 

You wouldn’t be wrong to list any of those, but while these physical attributes may influence initial attraction, psychologists claim that there are other important factors that have a lot more to do with who we choose to have long-term relationships with. Believe it or not, our genes, too, have a huge role to play in determining who we get attracted to. But how do our genes do such a thing? Well, the answer lies in… your nose.

 

We know that both men and women want to make healthy babies with robust immune systems that can fight off disease. The MHC (Major histocompatibility complex) genes are involved in the formation of our immune system and when it comes to this group of genes, opposites attract.  

 

Interestingly, our human instinct primes us to choose a mate with a very different immune system to our own because it ensures that the offspring can defend itself against illness. To test this out, Wedekind et al. (1995) conducted a study, which is now eminently known as the ‘Sweaty T-Shirt Study’.

 

In the Sweaty T-Shirt Study, 49 female and 45 male university students were typed for their MHC genes. The men were asked to wear a cotton t-shirt for two consecutive nights and were told not to use deodorants or perfumes. These sweaty t-shirts were then placed in a box with a hole and given to the female participants to sniff (each one of them got six t-shirts, three worn by MHC-dissimilar and three worn by MHC-similar men). They were then asked to rate the odour on a scale from 0 to 10 for intensity and pleasantness, given that MHC information is known to be encoded by one’s body odour. What made this study even more fascinating was that it followed a double-blind design (neither the participants nor the researchers were aware of which box had which t-shirt). Ultimately, the findings showed that the female participants rated the odour of MHC-dissimilar men as more pleasant and attractive than that of MHC-similar men, clearly supporting the theory of natural selection.

 

Through this intriguing study, Claus Wedekind demonstrated how our human instincts have evolved to pick up invisible signals to find the most ‘compatible’ partner. So, the lesson to take back from this would be that the next time you decide to step out of your house to find ‘the one’, maybe try sniffing a bit harder…

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Written by: Eshaan Soni 

Edited by: Unnathi Kumar 

Designed by: Saisha Singh & Aradhya Poddar