Tuesday, August 17, 2010

From the Archives: Smelling on the Right Side of the Brain

I'm taking a couple of weeks off to work on another project. I'll be back with a brand-new post on Tuesday the 31st. In the meantime, I'm putting up a couple of my old favorites you might not have read, hence:

From the archives: originally posted on Nov. 30, 2008:

Awhile back, I was evaluating perfumes, using smelling strips.  (A hint: make them from a good-quality watercolor paper; it’s thicker, the base notes last longer, and you’ll get many hundreds of strips from one sheet.)

I noticed that the scents I tested seemed much stronger and more pleasant when I covered my left nostril and smelled only with my right. I have a slightly deviated septum on the left side, so that pathway is a bit smaller on me, but I began to wonder: is smell more a right-brain function than a left-brain one?

For years, it has been an axiom that the left side of the brain is, let’s say, the “Lawyer:” verbal, analytical, somewhat condescending (well, not really) – the brain’s Cop, in other words. The right side is the “Artist” – chaotic, spatial, creative, impractical. Assuming that this is true, I began to think that perhaps it wasn’t so much my narrowed sinus passageway as general neurophysiology that resulted in the difference I perceived. So I decided to do some (very) primary research.

By cutting narrow enough smelling strips, I was able to get closer to the olfactory nerve endings by on that side by, well, the rather gross procedure of, um, introducing…oh all right, shoving…the strip further up that nostril than the other one.

I thought, hmmm…left brain…from what I know about hemispheric dominance, it should be easier to identify the “notes” using that verbal, analytical side.

Guess what; it wasn’t.

I hit the books.

It appears, from a number of scientific papers I examined, that the right nostril is somewhat dominant in subjects with intact brains. I say this because brain researchers just love to use people whose brains have been “resectioned” – as is sometimes done to relieve severe epilepsy – when doing this kind of research. The crossover networks that make the two hemispheres communicate are, to grossly oversimplify the procedure for brevity here, cut. Therefore, when using FMRI – “functional” MRI, which shows imaged patterns of brain activity as they occur – they can see the two hemispheres’ activity with less interference from crossover circuitry than they would in a normal brain.

My own brain is reasonably intact, so it would be reasonable to assume that my right nostril would be the preferred one for scent evaluation, and it is. There simply is a bigger, more pleasurable sensory experience; when I close off the right nostril, the experience of smelling only with the left one is, well, puny by comparison, even with the scent strip placed closer to my olfactory nerve endings.

The research on this is not perfect, as with most research. Complicating factors include handedness – left-handed people do better in odor discrimination tests (analyzing/classifying the scent) when the odor is introduced into the left nostril, whereas there’s little difference in right-handed people. (I’m right-handed; interesting.) Women are better at “naming” than men, as women tend to be better at anything verbal. Re-test reliability is somewhat uncertain. Subjects tend to be college students, as with most research of this type. And so on.

What we do, meaning us perfume fans and bloggers, is experience scent, then analyze it. We classify, identify and label its components. We’re familiar with the ingredients of perfume; in this research, that’s called “priming.” They put you through a practice run, and test you again later; semantic, or verbal, memory therefore crashes the party. This kind of memory does not appear to be right-brain dominant.

Perfumistas “prime” ourselves all the time. It’s what we do. Is that jasmine, or tuberose? Hmmm…does it smell more like “A La Nuit” or “Fracas?”

My own guess is that, as we develop the olfactory sense with all of this “priming,” we establish better crossover patterns from right hemisphere (olfactory perception) to left (olfactory analysis). Also, it appears that neural activation patterns develop after repeated presentations of complex odors, which could be part of the process, too.

As a semi-noob, my crossovers aren’t all that great yet. But they’re getting better.

Want to do an experiment? Smell a perfume you’re not familiar with, using your right, then left, nostril. Write down your impressions, and what you think the “notes” might be, with each. Then ask a friend who is not a perfumista to do the same.

Let me know what happens, eh?

PLEASE NOTE: The comments are from the original 2008 post. This one is not connected with any drawing or contest. But if you want to leave a new comment, feel free!
For anyone who would like the read the scientific papers and abstracts I based some of this entry on, contact me in the comment; I’ll send you a list.


flittersniffer said...

I just tried smelling Marc Jacobs Amber with each nostril in turn. (I am right handed.) I want to lead with my left nostril every time I go to sniff something, and the impression is much stronger and more immediate up the left nostril. I am none the wiser as to the notes in this scent, though(I'm guessing amber?), regardless of the nostril deployed. I have a funny feeling my right nostril may be blocked. I do have sinus trouble, as it happens. That may just have scuppered the experiment...! : - )

Olfacta said...

Interesting! If I remember correctly, the researchers didn't use subjects with active sinusitis or a badly deviated septum. So that may be it. Or it just may be that we're all different and no one fits "the paradigm."