Monday, November 17, 2008

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.


Anonymous said...

Very interesting! From a sample of one scent, it seems to be a reasonable idea for me. The right nostril seems to get a slightly more nuanced version of the scent.

I'm ambidextrous, is that makes any difference. (And my brain is intact, as far as I know! )

No need to enter me in the drawing; I think the book may be coming from Santa! ;)


ScentScelf said...

Smiling and all excited, because I've got a complimentary fascination about "sided-ness": I SWEAR that scents smell different on my left vs right wrist sometimes. AND they last longer on the left.

No, I do not operate in such a way during the day that my dominant (right) hand activity wipes off the perfume; when I first noticed this, I conducted a few experiments (and observations) to see if that might be. (Writing by hand, for example? But it wasn't done on observation days.)

I certainly cotton to the nostril concept; having been in yoga classes and observed the dominant nostril shift, I believe that one side of the sniffer tends to work harder than the other at any given time.

Guess I'll have to run a few test strips to see what i find... :)

Perfumeshrine said...

It's a great article and I like your personal angle!

It goes without saying that as most of us smell things the exact same way, it's a process of elimination and "naming" which accounts for what is so randomly described as "having a good nose". And this is where many of those experiments are confusing because they invariably involve the verbal. It's also interesting to read Avery's chapter where he says that tests in which subjects were told they would smell something (with different nuances of positive/negative or lack thereof) mass-suggestion worked too!!

(ps. No need to deprive anyone of their chances on an Avery copy as I have already read it and reviewed it)

Olfacta said...

Hey E!

I think that is why the neurobiologists are so excited about doing FMRI (functional MRI) research. Involved areas of the brain "light up" in real-time, removing the verbal variable from the equation. It is, of course, extremely expensive, so I'm not sure exactly who would fund this kind of research IF it was done by the fragrance companies (but can guess...hey, maybe they're already doing it, who knows?)

Thanks for the comment!

P aka O

Olfacta said...

Hey C --

I'm thinking that you might be smelling your left arm with your left nostril primarily, and vice versa. I tend to "tilt" my head when arm-sniffing; could that be it? This is all so delightfully complicated...I suppose the right side/left side thing exists for most things, wine comes to mind -- but of course that's confounded by the taste sense.

maisqueperfume said...

interesting empiric experience.
I noticed the difference too, from one side to the other.
but I also noticed that one gets tired easily than the other.
But I would not find it strange.
Since I have sinusitis and rinitis, one side has always more mucus than the other. The humidity of the inner side of the nostril makes the difference I guess.

Good imput!

Anya said...

Great post, it shows you really delved into the subject, one that folks are just becoming aware of.

I've been teaching this method of scent evaluation for years, since I learned it from a kodo ceremony master. I believe this method of bilateral sniffing has been going on for centuries in the kodo ceremony, nice to see scientists now "discovering" it.

The perception differences are always a shock to my perfumery students, and sets them on the path to realizing there is a blend of art and science in perfumery.

Don't need to enter me into the Gilbert book draw - I already have it and reviewed it - wave to Helg ;-)

brian said...

Oh wow. What a fertile subject. And weird--I've got a deviated septum myself, and smelling out of my right nostril is severely handicapped I think. If I cover my left nostril and try to smell out of my right I can barely pick up anything, so all of my smelling is coming from the left. I've often wondered what that means. Mostly because I wonder if other people smell my cologne much more strongly than I do. Do I have to put more on to enjoy it myself, therefore assaulting other people? I have no way of knowing. And because my right nostril is deficient, do smells register differently to my brain and therefore my senses? People argue that everyone smells the same thing in a perfume but I suspect otherwise.

Olfacta said...

Hi Anya -- Thanks for reading!

Scentself mentioned the sniffing/breathing through alternate nostrils in yoga as well. I've done that too, as well as drawing with the non-dominant hand to "fire up" the other hemisphere of the brain. Do your students experience scents differently through alternating nostrils?

Olfacta said...

Hi Brian --

I think that many people have some degree of deviated septum, but, interestingly enough, didn't see that factor controlled for in any of the papers I read, although there is some reference in one to "introducing" odors via a tube inserted into the nasal passageway...with greater success (the experimenter noted) when the subject is allowed to do his or her own "introduction." (Greater success in the rate at which the subjects actually show up, I'd bet.)

Although the studies were conclusive, they weren't hugely so; there is a slight right-hemi dominance in intact-brain subjects. And the body does tend to compensate for the sake of symmetry. My guess is that your crossover networks work overtime, especially since you actually analyze the scents as opposed to just perceiving them. Interesting though!

Chi said...

Something I've never though much about before! Very interesting stuff :) I'd love to check out the book too! Thanks for the giveaway :)


mark42 said...

Thanks for this interesting post. I tried the test as well and at first it was difficult to tell if there was a difference or if it was psychological. I tried with iso e super, which is very subtle, labdanum which is not and a methyl ionone - in between. Now I've got to thinking that I have a deviated whatchamacallit on the right side as well because it was definitely harder to get the air flowing through that nostril.
Funny, though. When I did the 'deviated septum bypass' technique, my left side was definitely more perceptive.
I wonder if the brain compensates for having one nostril slightly blocked by connecting more neurons on the good side.

Include me in the book draw, please - this is all fascinating stuff.

Holly Simpson said...

Great article indeed - many thanks. As mentioned in another post re yoga, I came across this in yoga classes over the years, but never did think to apply the concept to perfume! I read somewhere recently, a study done by a uni in California [I think], that choice of nostril affects how the brain will interpret each smell and the right side was generally rated as more pleasant.

Would love to be entered into the book draw!

Kind regards

Olfacta said...

I think that study was done at UC Irvine. It was one of the ones I looked at. Of course the verbal "naming" variable always comes into play, unless it's FMRI research; still, it does look like the initial impressions are performed by the right side.


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