A new study in Science shows that the human nose, long thought to be dull, can distinguish between one trillion (1 000 000 000 000) different scents. Not having one trillion different scents handy, researchers used the next best thing: math. Just like there’s a limit to how similar to colors can be in order to tell them apart, the nose also has a finite resolution. Researchers created new odorants (i.e. smelly substances) that were quantifiably similar to the others. Their results showed that, on average, people could distinguish between smells that were at least 49% different.
The greater than 49% difference was then multiplied by the entirety of all smell possibilities, and lo and behold, that this estimates over one trillion unique smells could be smelled by a person. How many of those smells we encounter in our daily lives is another question (my guess is less than 0.000001%).
But the article did spark an idea. My entire adult life, I have been self-conscious of how terribly I smell. Not because I never found the right deodorant but because I don’t think my nose is as sharp as other noses. Maybe it was excessive childhood picking, or blowing, or making pig faces, but the fact remains that I don’t smell very well.
So I decided to change that. Or, at the very least, try to.
Like other sensory organs, the nose transduces the physical interaction between it and the environment to the on-off firing patterns of neurons, relaying those signals to the brain for processing. In the case of our schnoz, inhaling through the nose draws air into the nostrils. That air contains lots of things – including tiny particles of everything in the environment. That citrusy smell of a freshly peeled orange? That’s tiny particles of orange. The woody, smoky scent of firewood? Small wafts of actual wood molecules. And that smell from an overly used Port-a-Pody? Little bits of poo flying up your snout.
When the odor particle (poo or otherwise) comes into your nose, it bumps into smell receptors that line the inside if your nostrils. Each particle has a different shape and each receptor has a different shape needed to activate it – an olfactory lock and key. Once a matching particle and receptor connect, it turns that receptor on, sending the signal downstream to the collected, parsed, processed, and utilized.
I intend to invoke the magic spell of plasticity to improve my smelling process. I call it “magic” not in the sense that it doesn’t work, but magic in the sense that I can’t be entirely sure why it works. There are so many different levels at which my sense of smell can improve: it could be anything from an increase in olfactory receptor expression in my nose to greater top-down attention enhancing my perception of smells (or, highly likely, a combination at several levels along the pathway).
As a control, I performed a baseline test of my smelling abilities with the help of my live-in research assistant. I was blindfolded and performed two tests of olfactory discrimination: one “odd one out” paradigm in which I was presented three smells, two of which being identical, and tasked with finding the unique scent, as well as a simple “matching” paradigm determining if two scents were identical or not.
I used my spice rack for samples (which is a bit old, likely dulling the unique scent of each spice). Samples were chosen to be as reasonably difficult as possible (e.g. comparing parsley and oregano vs. comparing cinnamon and basil).
Here are the smells I tested against: basil, parsley, paprika, ginger, cinnamon, thyme, and rosemary.
And here are my results:
– Odd One Out: 2/5 correct = 40%
– Matching: 3/5 correct = 60%
These scores indicated that I performed no better than chance – meaning that if I had flipped a coin instead of smelling, I would have been just as correct. To get my olfactory system up to snuff, I have begun a training regimen recommended by professional smellers, which includes being more “smell conscious” in everyday life as well as dedicated smelling practice.
I will keep at this for two weeks and test again. Hopefully, success will smell sweet.