Thursday, February 4, 2010

Olfactory Genius: Smells Real and Imagined

What are the dimensions of olfactory talent? Everyone’s first guess—that smell sensitivity separates perfumers from the rest of us—is certainly wrong. What does set experts apart is the ability to think about odors in a certain way. For the olfactively gifted smells are easily discernable, almost palpable objects hedged round with associations and synaesthetically linked to sounds, colors and shapes. In other words, pure nose power is overshadowed by the cognitive talents of memory and imagination.

The ability to imagine a specific smell—to summon it up from memory in a vivid way—is central to smell creativity, whether the result is a perfumer’s formulation or the invocation of scent by a poet or novelist. In What the Nose Knows, I spend a chapter describing three traits of creative olfactory genius, drawing on the work of writers, musicians, and other artists. 

As a scientist working in the perfume industry I tackled the topic empirically. Along with my colleagues Sarah Kemp and Melissa Crouch, I created an olfactory version of a standard research questionnaire used to measure the vividness of a person’s mental imagery. We gave the Vividness of Olfactory Imagery Questionnaire (or VOIQ) to perfumers and other fragrance professionals, and compared their scores to those of non-experts. The perfumers had more vivid mental impressions of smell. In another study, I found that high odor imagers bought and used fragranced products more than low odor imagers.

Since then other researchers have found that VOIQ score predicts all sorts of odor-related behaviors. For example, psychologists Richard Stevenson and Trevor Case studied smells during dreaming.
They discovered multiple links between dream smelling and smell ability in the waking world. First, olfactory dreamers experience both visual and olfactory imagery more vividly than non-olfactory dreamers. Second, people with more vivid mental imagery for smells have more vivid smell dreams. A follow-up experiment found a third link: olfactory dreamers are better at identifying odors in a smell test. 

All of this suggests to me that some people are simply more tuned into odors than others. Smell-oriented people—those who identify odors accurately and imagine them vividly—tend to dream in smell as well. Olfactory talent shows itself all around the clock.

In recently published experiments, psychologist Catherine Rouby and co-workers at the Claude Bernard University of Lyon, France take things even further. Rouby gave the VOIQ (and its original visual version, the VVIQ) to 30 people, who then rated the smell of carvone, isoamyl acetate, and limonene for intensity, pleasantness and familiarity.
A second study also began with 30 people who took the VOIQ and VVIQ, but only the eight top-scoring good imagers and eight bottom-scoring poor imagers proceeded to the next stage: rating cineole, isoamyl acetate, and heptanal for intensity, pleasantness and familiarity. While doing so the subjects wore a nose mask equipped with an airflow sensor that measured sniffs.

Rouby’s team found that good visual and olfactory imagery go hand in hand. They also found that good olfactory imagers rate smells as more intense, familiar and edible than do poor olfactory imagers. They also sniff longer at all odors, regardless of the pleasantness of the odors. 

To the French team these results support “the hypothesis of deeper or more complete odor processing and better access to odor semantics in good olfactory imagers.” That’s a more precise and graceful way of saying that good olfactory imagers are “more tuned into odors.” 

Rouby’s results are further confirmation of the tight reciprocal links between sniffing behavior and the experience of real and imagined odors. People routinely sniff when asked to imagine a particular smell; in doing so, they activate an entire sensorimotor sequence that enhances the vividness of the imagined odor, just as eye movements during visual imagery help us “see” a specific picture in our mind.

All in all, what emerges from the new sensory neuroscience of smell is a view of odor perception as cognitive and motoric—hardly the all-emotion all-the-time caricature that used to prevail.


BitterGrace said...

Fascinating stuff that seems to confirm the experience of most scent freaks. The pleasure or pain of sniffing is inseparable from imaginative engagement.

Maybe I didn't read the dream smells post closely enough, but I didn't see a discussion of the percentage of olfactory dreams that definitely have no external stimulus. How many of us routinely dream in smells that aren't actually present?

Ed C said...

Can this critical olfactive imagery be imporved? That is, are we (a) born with a certain ability, (b) accidentally develop some level of ability early in life while the brain is still most plastic, (c) trainable at any age to make more connections, associations, etc., or (d) it's something else I haven't thought of? I obviously hope the answer is (c) But I've never found any description of an olfactive imaging training program.


Nukapai said...

Oh wow! I would LOVE to do that questionnaire! (I'm a trainee perfumer and have had a fabulous week in the lab this week - finally cracked something that had been bugging me and funnily enough, I've been formulating in my dreams and then wake up with the solution!).

queen_cupcake said...

I find this incredibly interesting, and like Ed C, would love to know the answers to his questions. Thank you.

Avery Gilbert said...

Ed C & Queen Cupcake:

My late friend the social psychologist John Sabini claimed he had no visual mental imagery. I used to think he was just being provocative but it turns out there’s a good deal of variation in this ability. So maybe he wasn’t much of an imager—although he excelled at logic and rhetorical analysis.

On the other hand, imaginary perception can be powerful enough to substitute for actual perception: think of Beethoven composing while deaf, or the perfumer who allegedly continued to formulate after losing his sense of smell.

As I note in WTNK, the core of perfumery training consists of memorizing hundreds of smells; imagery is helpful if not essential to this task. I’d bet that with practice a person with modest olfactory imagery could improve it, and I’d also bet that evidence of this could be seen with fMRI imaging.

Avery Gilbert said...

BitterGrace & Nukapai:

The first studies, over 100 years ago, put the percentage of olfactory dreams at no more than 20% of all dreams. A McGill study in 1998 using dream diaries put the number closer to 1%; however, 21% of women and 2% of the men had had at least one scented dream in their life. My take: dream smelling is a widespread but low frequency phenomenon that has a female gender bias.

Among female scent enthusiasts & perfumers, I'd expect the percentages to be higher.

Nukapai said...

That's really fascinating; I am now tempted to record instances of scented dreams and try to work out how often they occur over a year. Mr. Gilbert, your data and methods appeal to the geek AND the perfumer in me. (Hope you'll write another book one day). :)

carmencanada said...

Re: Ed C's question.

When I gave my perfume appreciation course at the London College of Fashion, I had a very diverse group of 15 people (age, country of origin, profession, level of knowledge/interest in perfume).

I found that the ability to connect smells to words, or smells between themselves, was indeed very variable, and not necessarily related to a developed "perfume culture". My 15-people sample was certainly insufficient and there was no formal method of evaluation, but the two 50-something, non-perfumista members of the group had two the keenest noses. I put it down to having more scent-memories in store. I did find that everybody's ability developed within a few hours, so that I'm fairly confident that training and focus (synaesthetic associations, verbal cues) can develop the "tuning-in".

I have found this to be true for myself: the more I study perfumes and raw materials, the more frequently I "hallucinate" smells that aren't there, sometimes through random thought processes, sometimes when I am speaking or thinking about them, but oddly, more often when I'm speaking.

In a totally unscientific way, I feel the neural pathways associating smells to words are becoming more entrenched, and thus, easier to find/travel on.
I suspect this is the case for many perfume lovers, and probably often dictates their choice of fragrance in the morning.

Ed C said...

This has interested me enough to find some psych papers on olfactory imaging. As of 2004-2005, the ones I found began by saying that the very existence of the ability to menatlly re-expereince a smell was controversial. Each paper concluded that some people probably can do it some of the time. I haven't finished the long review yet, but in what I've read, Avery was the only one who studied any professionals at all. It occurs to me that the existence of visual imagery might be controversial if no painters, sculptors, photographers, architects or interior designers were ever studied.

How much of our poor ability to imagine smells is because we are never trained? We won't know until there's some method of training that can be widely applied.

Avery Gilbert said...


Maybe you can dream up some wonderful scents to fill the geek-chic niche.

Transformed by Fourier

Fitted Curve--the new skin scent with exponential smoothing.

Autocorrelation--for the naughty statistician in you.

Avery Gilbert said...


Well observed. As a teacher you notice differences among people who are presumably highly motivated to begin with. Think how much bigger the variation is in a random sample of people.

To Ed C's point--there ought to be aptitude and achievement tests for smell. The former to identify prospects for perfumery school, the latter to measure the effectiveness of the training. I don't know of any tests that have been rigorously studied.

Nukapai said...

Brilliant :D :D :D Those definitely tickled me. Maybe I could make First Nerve - for the true perfumphile. :)

Nukapai said...

You know, I was thinking on the way home today that it'd be super-fascinating to test how much correlation there is between people who have exceptionally well developed ability to recognise patterns and olfactory ability/genius. Unless it's already been done?