At the Secret Garden Party this July, we will host a Feast of Stenches with molecular immunologist Dr Leslie Knapp. We will re-create the famed “t-shirt experiments”, which have examined how research subjects will preferentially rate different human smells – in the form of dirty t-shirts – for their attractiveness. 

Remarkably, research has shown that our preferences for smells are determined by subconscious genetic cues. The same genes that determine how we smell – known as the “MHC cluster” in animals and the “HLA” in humans – also play a key role in programming how our immune systems operate by determining what innate and individual resiliences we all possess. A short film on the wonderful American network PBS can be seen here.

Lab animals as well as people will preferentially choose mates who possess MHC clusters that are different from their own, which most scientists believe acts as a subconscious mechanism that protects against inbreeding. Dr Knapp’s own research on mandrills has demonstrated that individuals will use smell to “identify potential partners with the appropriate genes,” as she puts it.

In humans, some fascinating studies (such as this one) have found that when women are shown photographs of men and given a selection of smell samples from the same men (though without knowing which smell belonged to which man), their choices frequently matched: the scents they deemed sexy often came from faces they declared handsome.

“We humans usually think that we pick our mates according to how they look – we first think of ‘love at first sight’ – we don’t appreciate the importance of smell,” she says. “But studies of primates and even studies of humans have shown that our ability to smell is very important, even in present day society – how we perceive the smell of someone has an influence on how we react to them, and there is good evidence to suggest that it has important influences on how we choose our mates.”