January 28, 2013

Quantum smell.

"It challenges the notion that our sense of smell depends only on the shapes of molecules we sniff in the air."

24 comments:

Mitchell the Bat said...

Looks like the BBC News is now using an app to rewrite the press releases.

rhhardin said...

That's why you never know what the smell is and who caused it both at once.

The operators don't commute.

chickelit said...

One way to test the idea was to prepare two molecules of identical shape but with different vibrations - done by replacing a molecule's hydrogen atoms with their heavier cousins called deuterium.

Fascinating, Althouse! Deuterium isotope effects used to be my bread and butter (crackers and margarine, really).

Did you know these things all trace back to Einstein and Otto Stern and 1913? Zero-point energies. There was a WW II connect too, obfuscated at my blog. But that's another story.

traditionalguy said...

Once again settled science that really did not explain the facts has now re-settled on another guess.

If good vibrations are what makes things smell , then that could explain why a smell sets off memories from good interactions out of the past.

Schorsch said...

I'm a research scientist working in olfaction. This is an example of precisely how science should not be done.

Turin had an idea, based on a gut
feeling of how olfaction works. That's great. Science is more gut-based than you might think. The proper way to proceed is to design experiments, test hypotheses, and attempt to collect evidence that supports your hypotheses. Turin wrote a paper with no data, and insisted that Nature, the premier science journal, publish it. When they reviewed and rejected it as baseless, he went on a P.R. campaign claiming a conspiracy to keep out his ideas. A very popular book was written about him and his ideas (not "theories," as theory requires supporting evidence).

Others have gamely tested his hypotheses and they have all failed. This is the first I've heard of supporting evidence, and I am not surprised he went straight to the media.

Fundamentally, you cannot infer much from his experiments, because they rely on the a human reporting what they smell. He wants to say he has proof of a very odd mechanism, found nowhere else in nature, that is operating at the very first step of smelling an odor. If you want to describe a new paradigm in biology, you need extraordinarily compelling evidence. Preferably direct evidence of the actual mechanism, not just its effects.

There are a thousand wrong ideas for every right idea in science. Accumulations of evidence over many years is the only way to tell the difference.

Pogo said...

Schorsch smells a rat.

Very helpful!

Darrell said...

If good vibrations are what makes things smell , then that could explain why a smell sets off memories from good interactions out of the past.

Our brains seem to use sequential access, rather than random. "Smells" are memories, too, and stored as such. All memories have some tag that indicates when it was "recorded" and often other memories with a similiar "date" tag get pulled up along with the "record" sought. Déjà vu is probably an error with the indexing system. Something we are seeing for the first time now somehow gets tagged with an old index marker. We not only recall a "memory" but also get a sense of when we "recorded" it. That--and the other memories with a similiar "timestamp" would come in handy if there was danger in the first encounter with that memory, e.g., certain smell--->tiger.

Tibore said...

The research so far is not conclusive. The authors of the paper at the PLOS ONE link come out and admit this:

"The experimental evidence on this question to date is contradictory. Drosophila appears able to recognize the presence of deuterium in odorant isotopomers by a vibrational mechanism. Partial deuteration of insect pheromones reduces electroantennogram response amplitudes. Fish have been reported to be able to distinguish isotopomers of glycine by smell. However, human trials using commercially available deuterated odorants [benzaldehyde and acetophenone] have yielded conflicting results, both positive and negative."

Or in short, it's not so simple as to say it's either just shape or that "vibrations" are the real effect. I'd say that the BBC is making note of this research a bit prematurely, as the conclusions are obviously far from firm.

edutcher said...

If so, nothing makes the ol' molecules vibrate like the exhalation of a Yorkie puppy. Their breath can melt steel.

PS Smelly?

How 'bout olfactories?

Tibore said...

Oh. Just saw Schorsch's info. Fascinating.

And he's right: Experiments testing hypotheses and evidence collection from those is the way to proceed. By the way, is more information available regarding the claim of Turin circumventing standard publication procedures? I'm not refuting the claim that he did it; rather, I'm not familiar with the specific topic and was looking for overviews to learn more.

chickelit said...

@Schorsch: Deuterium equilibrium isotope effects are well established. For example, D2 binds 1.4 times better to certain tungsten complexes than H2 does; Perdeuterated ethylene binds 1.4 times better than C2H4 does as well. These are quantum effects, based, as I said, on zero-point energies. In sense (pun intended), these are molecular recognition phenomena. I agree that it's a stretch (another pun intended) that such effects could be translated (yet another pun) to smell recognition, but give the man his due(terium). :)

Darrell said...

Febreze--Hydroxypropyl beta-cyclodextrin or HPβCD---was the first deordorizer to attempt to change the shape of the odor molecule by binding to it and changing human perception--and it worked amazing well, IMHO. It was the first thing I ever found to get old pet urine odor out of an expensive hand-woven rug. Something that repeated gentle washings and other deordorizers had never done. When I heard that the original formulation was going to be changed because P&G didn't want to defend a chemical product that didn't have a long-history of usuage and health studies, I stocked up on the old. I still use it and it still works. The reformulated stuff is no where near as effective.

Palladian said...

"Smells" are memories, too, and stored as such.

But they're not memories, because we can (and do) smell new and unique molecules all the time.

Palladian said...

I'm happy to count Dr Turin as a friend of mine.

MadisonMan said...

I find the science of smell to be absolutely fascinating, so thanks for this link. I'm not volunteering my nose for the receptor study however.

Prof. Vosshall comes off as way too condescending in the article. She needs to sniff out a better metaphor, one that doesn't include unicorns.

traditionalguy said...

If this research has something to do with wine tasting, then I volunteer.

Wine and food pairings tests will require a huge federal research grant because French Restaurants and French gastronomic societies are very expensive. But anything for pure science.

Darrell said...

But they're not memories, because we can (and do) smell new and unique molecules all the time

When they are stored in short, medium, or long-term memory, they are memories. "New" smells have to be compared with something to be judged as such, no? We "see" new images evry day--new things and people--yet you have memories of people and images, correct? And we can come up with "names" when the images match our MEMORY?

n.n said...

There is an outstanding, unanswerable challenge to explain the interpretive center. We will identify different modes of coupling. We will identify different modes of sensing. We will never identify the means by which we perceive and interpret our environment or consciousness.

Anyway, science should serve a utilitarian purpose, to advance the human condition. It should be carefully distinguished from philosophy and matters of faith. It has been a conflation of science and philosophy, especially today, which has provided justification for violation of human and civil rights.

chickelit said...

n.n. writes: Anyway, science should serve a utilitarian purpose, to advance the human condition.

Careful there, n.n. I'm wondering if you're not Locke'd into a philosophy yourself. Pure science is curiosity-driven and often is without practical purpose. Invention and technology is another matter, and requires utility (35 USC § 101), at least for government and commercial recognition. Einstein patented his refrigerator, but not the stuff we remember. When science is driven for pure practical aims, we get policy-driven results.

@Palladian: anch'io!

Palladian said...

Chick, you know him too?

traditionalguy said...

I for one am against Conflation. But everybody is doing it these days.

Maybe that's because people are so smart that knowing the words of several categories they like to string them together like a Picasso painting.

Then when I tell them they are creating a straw man argument, they pretend not to hear me.

chickelit said...

Nope. Just heard about him today. But I've met a few of the "movers and shakers" in the isotope effect world.

Baron Zemo said...

"Quantum Smell."

For a minute there I thought this was a post about Mariah Carey on American Idol.

Palladian said...

Ah. I became friends with Turin through a blog he used to keep. He once wrote a nice bit about me in his column in the Swiss magazine NZZ Folio. He's amazingly entertaining when discussing almost any subject, and he writes quite accessibly about very complicated science. Buy his book "The Secret of Scent" (through the Althouse Amazon portal, natch) if you're interested in the development of his theory of olfaction.