How does your brain determine what smells ‘good’ and what smells ‘bad’?

If you’ve read the information on our website all about how the olfactory system works, you’ll know that thanks to the air being filled with aroma compounds, and our very clever nasal receptors which have a direct pathway to the brain, we humans are – generally speaking – naturally tuned to deciphering all kinds of smells.

But what determines a ‘good’ smell from a ‘bad’ smell?

In part it’s down to our own life experiences. That time that your grandmother made the best lasagne and you enjoyed it together as a family. This triggers your brain to release chemicals that make you feel good. The sweet smell of cherry blossoms in Spring that are enjoyed by the birds on a sunny day = good smell. Smell has a direct link to our ability to make and recall memories.

In part it’s down to our natural instincts that are part of us as a species. For example the smell of blood is known to be unpleasant to humans, and to animals that are vegetarian and/or prey. But delectable to animals known for their hunting prowess. 

Or perhaps you ate something once that was off and it made you sick, so now the smell of that thing is enough to make your stomach turn. That’s your memory kicking in to stop you from eating something that could be bad for you. 

‘Bad’ smells are often linked to bacteria that are known to cause stomach upsets or be dangerous to humans and our brains are hardwired to be repulsed by these. 

If a particular smell which others might consider ‘good’ actually makes you feel the opposite way, it’s likely because you have a bad memory attached to it. Heartbreak? A big night out? The possibilities are endless!

The way that our scent ability and memory is so intricately linked has led scientists to explore this area in more depth which is starting to produce some very interesting studies on ways to manage neurological disorders such as dementia.

One thing is for sure - being aware of how well your sense of smell is working, and identifying different smells as you go about your daily tasks is a good first step towards olfactory wellbeing!