Freshly Baked Science
Why do we have different smell preferences?
11th December 2018
You may have noticed that a human’s sense of smell is extremely diverse. A great example of this diversity is petrol. Have you ever been to a petrol station with someone who has admitted their love for the smell of petrol and opened the window to get the full sniffing capacity, while you’re sitting holding your nose and gagging at the smell? If you haven’t, you’re probably the one who can’t get enough of the smell! The point is that there are smells which some people absolutely love, while others think it’s revolting… so why is this?
To understand why people have different scent preferences and aversions, we need to first understand how we perceive smell. Odours in the air are drawn into our nose when we breathe in and bind to receptors (olfactory receptors) in our nasal cavity. This binding process transmits signals to the parts of our brain responsible for smell identification, memory and emotion.
We, humans, have over 400 genes in our DNA which code for olfactory receptors, which is a huge amount for such a small part of the human body! This means that the set of receptors in our noses are more unique than you may think, with over 900,000 possible combinations of ‘smell genes’! The slightest difference in the genetic makeup of a receptor can be the difference between a scent being delicious or awful!
Our sense of smell isn’t just down to our genetics though! As mentioned previously, our sense of smell is connected with a portion of our brain that is responsible for memories. This means that we can create psychological preferences and aversions to certain smells. If we associate a smell with a good memory, for example, the perfume your Grandmother wears or the smell of freshly cut grass from having picnics with your family in the summer, then you are more likely to like to smell. On the other hand, if you associate a smell with a bad memory, i.e. the perfume you were wearing during an accident or being pushed over onto fresh cut grass, then you are more likely to dislike the smell!
It may be an interesting test to see if you can train yourself to like a certain smell that you used to dislike! Try carrying around a tissue with a perfume you don’t like sprayed on it, and smell it every time something good happens to you. Let us know what you find out by emailing us (firstname.lastname@example.org) or on social media (@wonkscience)!