Many animals rely heavily on their sense of smell for finding food, getting a whiff of the competition and even sniffing potential mates. You might not often see humans checking the scent of their partners, but scientists have found it does play a subtle role in helping us chose mates – as do perfumes.
All animals are made up of a collection of genes that are inherited from parents, these code for all sorts of things like eye colour and taste buds. All mammals, including us, have a section of genes called the major histocompatibility complex (MHC) which affects how well your immune system fights diseases. It is also linked to your natural scent.
There have been experiments on mice, mandrills, meerkats and many other animals showing that females tend to mate with males that have a different MHC to their own. This ensures that their offspring have a more varied set of genes and so will likely have a better immune system and survive for longer – which is what every parent wants for their child.
When tested in humans, the usual method is to get a group of men to wear a t-shirt for several days to get it nice and sweaty and smelly. Women will then smell each of the t-shirts and rate the odours in order of which they find the most pleasant. These experiments have consistently found that women tend to prefer the scent of men with MHC genes different to their own.
So what happens when you wear perfume and cover up that lovely natural odour of yours? Two researchers, Wedekind and Milinski wanted to find out. They asked over 100 people to rate a selection of perfumes based on whether they would like to smell like that. They found a correlation between the type of MHC and the scents selected, suggesting that we choose perfumes for ourselves that will enhance our natural odour. However, when asked to rate perfumes based on whether they would like their partner to smell like that, they found no significant link.
It appears that we are great a picking out odours for ourselves, but not so much at selecting the perfect perfume for others. Maybe a gift card would be better this year…