Why Do Scents Trigger Such Strong Memories and Emotions?

It has everything to do with the layout of our brains.

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Whenever I catch a whiff of chlorine, I’m reminded of the frigid early mornings and tiring late nights that I spent playing water polo as a teenager. The chlorine-induced memories are so strong, in fact, that I can even feel the cold water splashing against my skin.

Strangely enough, many of my old teammates share this bizarre experience: The smell of chlorine instantly floods their brains with distinct memories of lengthy training sessions and endless laps.

We’re far from alone in finding our memories so strongly triggered by specific smells: Scientific studies have actually proven that smell, more than any other sense, triggers intense memories and emotions. One 2004 study, for example, found that a group of five women showed more brain activity when smelling perfume that they associated with a positive memory than when smelling perfume they had never smelled before. The brain activity sparked by the memorable perfume was also even greater than the brain activity motivated by being shown the actual bottle, proving that our sense of smell evokes much stronger memories than our sense of sight.

But why exactly do certain smells trigger such strong memories and emotions? The answer probably has to do with the anatomy of our brains. Incoming scents are initially processed by the olfactory bulb, which just so happens to be connected to two areas of the brain that are also associated with memory and emotion: The amygdala and the hippocampus. The areas of the brain that process visual, auditory and tactile information aren’t associated with these structures, hence smell producing a stronger memory/emotion connection. Another 2016 study even found that memories evoked by odors are linked to more brain activity in areas associated with visual vividness, which also explains why I can literally see the pool in my mind whenever I catch a whiff of chlorine.

But smells don’t only trigger strong memories and emotions—they can also trigger very strong, er… bodily responses. More specifically, one 2014 study found that food smells essentially act as an aphrodisiac, resulting in increased blood flow to the penis. ‘It appears that food odors elicit the greatest sexual response,” Alan Hirsch of Chicago’s Smell & Taste Treatment and Research Foundation confirmed to Thought Catalog in 2015.

So next time you need to refresh your memory (or, y’know, refresh your peen…) consider taking a long, hard sniff of your favorite odor.