Ever smelt an old fragrance and get hit with an important memory? An anniversary, a birthday or even something from your childhood?

That's because smell is strongest sense tied to memory

Smell signals bypass the relay centre in your brain and pretty reaches the parts of your brain responsible for emotion and memory. Signals from all other sense has to first make a pitstop at a part of your brain called the thalamus before it sends other signals to other parts of your brain

Smell however, is different; you sense it then think about it

Strong emotions and memories will come up with certain scents. Good, bad and every memory in between. Since smell is sent on those pathways before you have time to really think about it, we are going to be emotionally reacting to a smell and potentially evoke a memory if we have a strong memory associated with that smell.

Stress makes a smell more memorable

The stress hormone, cortisol is responsible. Cortisol increases your sense of smell, making it more sensitive. As your body becomes more hyper aware of its surroundings, if there is a distinctive smell that it associates with where you are, who you are with and what you are doing, it will tie together with that memory. 

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