Sniff, sniff – there’s something in the air.
Is it fresh cut grass, the aroma of borscht cooking? Is it the stench of durian?
When compared with our other four senses, our sense of smell goes rather unnoticed.
Unless there’s a strong repulsion or attraction to an odor, this sense wafts under the radar.
And, yet, it’s one of our most powerful senses.
A Rose By Any Other Name…
Rockefeller University’s Andreas Keller conducted research on smell perception that demonstrated just how sensitive our sense of smell can be.
There’s a diverse complexity in scent that is unrivaled by sight and sound. The scent composition of a rose, alone, contains around 275 elements.
And humans can differentiate between trillions of these scents, according to Keller.
Keller’s study, published in Science Magazine in 2014, tested the capacity of humans to determine differences in various odor mixtures that had different shared components.
Their conclusion that humans can discriminate between upwards of a trillion odors far surpassed previous scientific literature, which determined 10,000 odors was our limit.
Comparably, we can only see somewhere between 2.3 to 7.5 million colors, and we can only hear 340,000 sounds.
As quoted in Keller’s abstract:
“[This research] demonstrates that the human olfactory system, with its hundreds of different olfactory receptors, far outperforms the other senses in the number of physically different stimuli it can discriminate.”
When it comes to the schnoz, the ear and eye can’t compare.
Evolution of Scent
Darwin knows the reason we can discriminate minute differences between odors: evolution.
What’s evolution got to do with it?
It turns out that smell is a handy tool for survival.
For instance, when we take week-old leftovers out of the fridge and give them a sniff, we can tell whether or not they’ve gone bad. If we crack that egg over the frying pan, and there’s a rancid odor, we know not to eat it.
So, if it’s a matter of life or death, the nose knows.
Another key factor in the study was that, when discerning scent, women regularly out-performed men. This may be because, throughout history, they most often prepared meals and had to know when food was rotten.
Animal Olfactory: How Do Humans Compare
After taking all this in, the human sense of smell may seem like a super power, but it falls way behind that of dogs and other animals.
Really, in the food chain of smell, we’d be on the bottom rung.
Think about it: this is the reason we use drug dogs at airports. Have you ever seen a customs officer sniff out a balloon of cocaine?
Regardless, our sense of smell is still incredibly sharp, and we’ll talk next week about how that sharpness impacts memory.