Maybe you’ve learned to dislike the smell. Maybe your socks are full of gross bacteria. Or maybe, it’s both. Our team studies the brain and sense of smell — it’s one of our favorite topics. But first, how do you smell?
What is that smell?
The air is filled with many small odor molecules which are released from “smelly” things like perfume or food. Your nose has the astonishing ability to smell thousands of different scents because in your nose are millions of — cells that can recognize odor molecules. When you sniff the air, these special cells are alerted.
These receptor cells then send a signal to your brain. Your brain recognizes many scents when different types of odors enter your nose. The smell of baking cookies, for instance, is composed of . Your brain can piece together all this information and let you know there are cookies baking in the oven.
Smells that make memories
One example of this is when you smell a favorite meal. It might remind you of someone who makes it for you, which triggers your brain to release chemicals that make you feel good and comforted.
Of course, smell can also be associated with unpleasant experiences. You have probably eaten some food that went bad, and you might find that you hate that food now. This is your brain associating getting sick with a certain smell, which stops you from eating something that could be bad for you. Memories linked to smells can form because of good and bad feelings.
Smells to warn you
But what about things that you know smell good or bad even if you’ve never experienced them? Scientists have found that although a lot of the smells people like come from past experiences, play a big role.
Scent tells you a lot about your environment, and your instincts help to decide what is safe or dangerous. For example, has been shown to repel humans and many prey species, like deer, but attract predators, like wolves. This guides people away from predators that might want to eat us, but lets the predator get its meal.
Smell can warn you when something could make you sick. When eggs rot, bacteria multiply like crazy inside them, that release a toxic chemical called hydrogen sulfide. This produces a stench that makes you want to stay far away, stopping you from eating the egg and becoming ill.