These molecules, they vibrate?
November 11, 2008 7:16 PM   Subscribe

The Science of Scent. An entertaining and enlightening TED talk by biophysicist Luca Turin.
posted by louche mustachio (20 comments total) 21 users marked this as a favorite
Previously, previouslier.
posted by louche mustachio at 7:17 PM on November 11, 2008

Fascinating, I'd never heard such a theory. Thank you.
posted by kisch mokusch at 7:53 PM on November 11, 2008

This is crazy far out. It's like something a hippie on LSD would dream up (or 19th century German literature, a reference I didn't understand). But he is able to make accurate predictions with the theory which is really powerful evidence. If we are able to sense molecules based on vibrational frequency, it opens up a whole new way to approach things.
posted by stbalbach at 7:57 PM on November 11, 2008

Why, oh why do I need sleep? Why can't I stay up until dawn exploring this TED talk? Drat. Will favorite now and watch later. Thanks for the post. Can't wait to watch the vid.

On preview, stbalbach, why oh WHY did your comment have to be so interesting and intriguing?! No fair! Want to watch the vid, must sleep. Sleep has to win.
posted by nickyskye at 8:51 PM on November 11, 2008

Absolutely read Emperor of Scent about Luca Turin. Amazing book, totally reworked the way I thought about scent and perfume. I have a whole new appreciation of after reading that and went out and bought a hand-made amber oil that perfectly suits me, a guy who had never been one to wear cologne. Great science, great anthropology, great biography.
posted by afflatus at 9:03 PM on November 11, 2008

Thanks! I enjoyed The Emperor of Scent and I was bummed when Turin stopped his blog. Nice to see some new stuff from him.
posted by twoleftfeet at 9:15 PM on November 11, 2008

Wonderful! I will definitely look into the book! Dang, I need a perfumery set, too!
posted by Ambrosia Voyeur at 11:02 PM on November 11, 2008

I enjoyed The Emperor of Scent, and his perfume review book is quite good. After reading both, I spent a Sunday afternoon at Macy's and Nordstrom smelling perfume samples. Usually I only see the inside of such stores when they are burning to the ground in my dreams of revolution.

While reading TES, I could never be sure if Turin is a real visionary, and his theories have some meat to them, or if he is a complete crackpot. He even scores some points in the crackpot index.

His paper(s) can be found online, but are beyond me. I had the same problem with them that he claims peer reviewers have had (peer reviewers who have always rejected the paper): he touches so many areas of specialization (chemistry, physics, neurology, evolution), that any typical scientist is bound to understand some parts and completely misunderstand others.

I hope his theories are part of what is making biology so exciting lately, people from domains of science that used to be kept separate coming together to figure out amazing stuff. Look at what has happened to evo-devo.

There is a rational basis for my hope, he got tired of trying to get his stuff published and recognized, and founded a start-up, flexitral. Applying his own theories, he was able to develop quite a few odorants, some of which have been tested and are commercially available. As the saying goes, the proof of the non-allergenic coumarin replacement is in the smell of newly-mown hay.
posted by Dataphage at 1:04 AM on November 12, 2008

Absolutely read Emperor of Scent about Luca Turin.

OK, *that* was the last thing I bought after a recommendation on Metafilter. I'm in no position to evaluate the science, but the story was fantastic.
posted by PeterMcDermott at 1:19 AM on November 12, 2008

Thanks for this! I bought and read EOS after the last MeFi post, it was fascinating.
posted by carter at 5:41 AM on November 12, 2008

*yawn* Another highly-entertaining TED Talk. Another great post from louche mustachio.

What I find fascinating is how the olfactory bulb sits in such close proximity to the limbic system, the centers of memory and emotion, in the brain, and how scents can trigger memories and emotions. Also the thing about pheromones.

Also how you can trigger a sneeze by looking at the sun. I was at one point a student in a Surgical Technologist program, and one day I was assisting a surgeon who, during the operation said she had to sneeze, and she looked up at the bright overhead light, hoping for a sneezy release. I said I'd heard that there are photo-sensitive nerves in the nose which are responsible for the phenomenon, and I suggested that because she was wearing a surgical mask, looking up at the light might not work. She didn't say anything for a really long time, but finally said, "I've never heard of photo-sensitive nerves in the nose. It can't be true." Nevertheless she did not sneeze.

You guys are probably familiar with the Black Phoenix Alchemy Lab, I only recently learned of it via the author Ekaterina Sedia's blog, and as long as we're talking about books here, I really enjoyed Sedia's two novels--
posted by Restless Day at 6:20 AM on November 12, 2008

Damn, it's no wonder people want to spam us, is it? It sounds like that last post on Turin sent sales of EOS soaring.
posted by PeterMcDermott at 6:35 AM on November 12, 2008

Also, interviewed on The Story in May 2007, which I only listened to the night before last:
posted by wenestvedt at 7:51 AM on November 12, 2008

Nice post, thanks. I'm going to get the book in my queue now too.

I started a job doing olfactory neuroscience a couple of months ago. Sitting on my desk right now are four separate lists of odorants, totaling about 550 organic compounds. We're looking into how the brain processes the sensory input, not how it is originated - so I can't really get into the specifics - but I'm skeptical that we can measure and respond to quantum effects.

It will take a lot of work to overturn the shape theory, or even to expand it to include an understanding of the quantum effects. This is a bigger problem than just how do we smell - the olfactory receptors are the same type as those which bind hormones and neurotransmitters. A complete understanding of how they work would really open up new frontiers in medicine and pharmacology.
posted by mbd1mbd1 at 9:27 AM on November 12, 2008 [1 favorite]


Do you know if anyone has checked to see if hormones and neurotransmitters have a smell?
posted by Dataphage at 4:43 PM on November 12, 2008

mbd1mbd1, I'm curious about your opinion on one of the central critiques that Turin makes of the shape theory. I know you haven't read the book yet, but one of his fundamental arguments of the shape theory is that we would have to have specialized receptors for a truly enormous number of molecules and that there is no evidence of that. The number of different molecules that are picked by the olfactory system is incredibly large and we are able to smell novel molecules that are created artificially. How would you account for that ability in a system that depends on receptors tied to existing shapes?

I certainly agree that Turin's hypothesis is by no means proven, but it does satisfy an essential set of criteria that I feel the shape theory fails at: it requires a small number of structures, it a general purpose mechanism and it allows for the recognition of novel inputs.

None of the neuroscientists I've hung out with do olfactory work though, so I'm keen to get opinions from others with more grounding in the area.
posted by afflatus at 9:43 PM on November 12, 2008

Well, the working assumption is that we discern odors based on their functional groups, so perhaps the receptors are binding to certain parts of the odor molecule instead of the exact shape of the whole molecule. In fact, people are working to decode all the combinations of receptors that react to a single odor. So a novel odor is just the sum of its parts.

I don't know of anyone who has tested the response to hormones or neurotransmitters.
posted by mbd1mbd1 at 6:59 AM on November 13, 2008

mbd1mbd1, send me a mefi mail when you get done reading the book, I'm genuinely curious about your take on it. Of course the book is 12 years old now (and a Nobel prize awarded for the theory that Turin takes to task).

Still, I haven't seen anything that shows why acetophenones smell so different from one another when their shapes are almost identical, yet hydrogen cyanide and benzaldehyde are structured very differently yet smell the same. (Both are examples from his book, btw).

Entirely possible that there has been work from the shape-theory camp in the intervening years that has addressed his criticisms and I just haven't seen it. "Mainstream theory addresses concerns of critics" isn't something that tends to get a lot of press, so I may have missed it.

Anyway, fascinating stuff all around and I would love to learn more.
posted by afflatus at 9:57 AM on November 13, 2008

but one of his fundamental arguments of the shape theory is that we would have to have specialized receptors for a truly enormous number of molecules and that there is no evidence of that.

I have no expertise in this field, but I do know that we have only a limited number of light receptors types in our eyes, and yet we can perceive an enormous variety of colours. As much as I'm intrigued by this theory, I don't think the old one can be dismissed on these grounds.
posted by kisch mokusch at 11:40 AM on November 13, 2008

Kisch Mokusch, the thing there is that the receptors in our eyes do not work by shape. They get excited by certain wavelengths/energies of the incoming light. That is actually what Turin proposes for olfactory receptors...recognition by detection of vibration.
posted by afflatus at 12:40 PM on November 16, 2008

« Older Darwin, extended   |   The gene is in an identity crisis Newer »

This thread has been archived and is closed to new comments