Wednesday, April 26, 2017

Thinking About Phylogenetics

Before you read this you should probably look around, to the left, and to the right. Every time you turn your head to one side or another, there is a part of your brain whose job it is to tell another part of your brain that your whole body is not spinning in circles, but only your head.

In other words, inside us is very old, hard-wired circuitry that still thinks our head is fixed to the rest of our bodies. Think about it – Necks are a pretty recent development. The first animals had no necks. Worms, fish – no necks. If their head was turning to the side, it meant their body was turning with it. Even eyes were developed after necks. Nowadays, when you, homo sapiens, turn your head to the side, one part of your brain cross-references with many other parts to check whether it is the entire head-body, or just the head: the eyes give data, the muscles of the neck especially, but also many other muscles of the body give information to help figure out what is actually happening.

You should be asking, why, after millennia of necks, have we not gotten rid of the automatic neural response to head movement which assumes the head and body are one? So much extra work to cancel out the false assumption… How is it that we still hold onto this little bit of circuitry, how is it that we haven’t gotten around to evolving our way out of this?

The answer is phylogenetics. The functioning of a brain is a palimpsest, or a city. Once the foundation is laid, it doesn’t change. You can work-around and retro-fit, but you cannot re-write. This creates all kinds of confusing and embarrassing problems where very old forms and functions end up mismatched with their current context. Smelling, certainly, is one of these things.

[Inspired by a Robert Sapolski lecture on human biology.]

Friday, April 21, 2017

Getting Old Stinks

World’s first – We developed technology to prevent “Nonenal” (component for a body odor in older people)
Shiseido successfully developed completely new technology that prevents body odor in the middle-aged and old people through joint research with Takasago International Corporation. Now we are in the aging society, more people are bothered by “body odor unique to middle-aged and old people”. Shiseido focused on the change in the body odor caused by aging and discovered “nonenal” which is an odor component that is found in many middle-aged and older people and the level of which increases with age. -source: Shiseido

Although, this isn’t the first time this has hit the news:
It Stinks: The Smell of Aging: Japanese researcher's discovery that older men emit a pungent body odor hit a nerve with the populace. Now companies have jumped in with products to mask the offending scent. July 14, 1999. Mark Magnier, Los Angeles Times.

“Shoji Nakamura, whose million-dollar nose is reputedly able to distinguish among some 2,000 different odors, says he first noticed a distinctive smell among middle-aged and older men in 1987 and spent the next decade thinking about it.

"I'm very interested in body odor," he says.

“Now, after painstaking research, Shiseido has acted on Nakamura's evident insight. This September, the company will unveil what it says is the world's first product line of shampoos, powders and air fresheners designed to block, cover and otherwise obscure the unique smell of growing old.”
-source: latimes

Perhaps I belabor this point, but once again I can’t resist. There is something quite different between the skin of Asians and that of Caucasians. White people have more body odor, because they have more of the glands that produce body odor hiding under their skin.

Aside, they also smell like cheese, according to the Vietnamese soldiers who could sniff them out of the jungle. They also smell “like wet dogs,” according to Google’s predictive search algorithm circa 2014 – you can no longer test this; the script must’ve changed; personally I think it was a very typical semantic conflation between wet dog, which is a very specific smell, and wet hot dogs, which actually has something to do with cheese, or at least I’m willing to bet. I’m not an expert here, only an enthusiast.

And to complete the run, the first result for “why do ____ people smell like” went like this:
Why do white people smell like wet dog?
Why do black people smell like crayons?
Why don’t Asian people smell? (I swear, it would rearrange your question to produce this)
And when it came to ‘Indian people,’ the question would get so rearranged that it just isn’t worth adding it to the list. Again, the scripts have changed since, and in 2017 there is no way in hell Google would allow that to happen. Sorry, wish I screenshotted that little piece of anthropological gold.

Back to the point; I bring this up about Asian people having less body odor because it makes it seem more obvious that a Japanese man would be trying to quell old-people odor and not simply (armpit) body odor. Anyway, thanks Shiseido, for reminding me of my inevitable end.

[After some further research]
Then again, in total contrary, check out this study by  Johan Lundstrom, a neuropsychologist at the Monell Chemical Senses Center in Philadelphia (Monell is one of the premier institutes for olfactory research). They had a whole bunch of people put handkerchiefs under their arms overnight, and then, after cutting-up and mixing the samples of similar people, they put the smell samples in corresponding jars for willing participants to investigate.

Conclusion: "It turned out that the underarm odor of 75-to-95-year-olds was judged to be less intense and far more pleasant than the scent of either young or middle-aged adults. The most intense — and perhaps not coincidentally, the most unpleasant — odor came from 45-to-55-year-old men. Women in that age group, on the other hand, produced the most pleasant smell of everyone who wore the underarm pads.

"On the whole, men generally smelled worse than women, but that distinction disappeared in old age, the researchers found.

"As you grow older, you smell more and more like a woman," Lundstrom said. That is due to changes in men's hormone levels as they age. "It's almost as if you're going back to what happened before puberty." source: latimes

Anyway, totally to the contrary of the things mentioned via Shiseido. But, kind of reinforcing the Asian body odor/Asian smell scientist theory.

-image source: Shiseido

More Old Folks Stuff –

Limbic Signal, 2016

Limbic Signal, 2016

Sunday, April 16, 2017

But Are You Sure You're Sure

Look carefully and tell me, what is this? Because it’s not what you think it is.
L’ange Du Foyeur, Max Ernst, 1937. Image source

Only because Hidden Scents presupposes that we are in the Age of Approximation do we pay attention to talk about certainty in science. The language of smell is anything but certain, and should make us second-guess what it means to “be sure” of something.  

Feb 2017,

Looking at 41,000 measurements of 3,200 quantities - from the mass of an electron to the carbon dating of a sample - Bailey found that anomalous observations happened up to 100,000 times more often than expected.

"The chance of large differences does not fall off exponentially as you'd expect in a normal bell curve," said Bailey.


"The study shows that researchers in many fields do a good job of estimating the size of typical errors in their measurements, but usually underestimate the chance of large errors," said Bailey, noting that the larger-than-expected frequency of large differences may be an almost inevitable consequence of the complex nature of scientific research.

"As measurements become more and more accurate, the smallest things matter more and more," Bailey said.


"These insights can be beneficial given the inherently complex nature of scientific research," says Bailey. "But the chance of avoiding being wrong in some way on some level is almost impossible."

Wednesday, April 12, 2017

Embryos Can Smell Too

Comparing the embryonic development of various animals, Ernst Haeckel's Art Forms in Nature                   

Among the myriad ways olfaction is set apart from all other senses, this is perhaps the most important – Smell is the first sense to develop in ontogeny (the ‘lifetime’ of an organism), and begins in the womb.

We know babies can hear in the womb, but it isn’t often considered that they can smell too. Smell is a form of chemosensation. And if we think of an embryo as floating in a chemical soup, it makes sense that such an organism would be able to sense its surroundings. Possibly more surprising than this, it should be noted that adult humans have olfactory receptors in other parts of their bodes besides the nose. Certain organs are populated by the same nerve cells that relay the presence of aromatic molecules to our thinking brains via olfactory perception.

Here we must distinguish between sensation and perception. It is a misnomer to say that an embryo, or any such simple organism, can smell. Can you see with your eyes closed? Well, yes, but it depends on what you mean. The photoreceptors in your eyes still work whether your eyes are open or closed. In fact, they never stop working. The “seeing” part of you may stop, but the receptors are on all that time, ready to be stimulated by the most gentle of photon showers. (And when there is none – they make things up!) Babies in utero too can sense light levels in this way – but is that “seeing”? Not so much. And is it the same with smelling? Sort of. Perception requires a brain, but to sense does not. Plants can smell. Not really though; they can only sense chemicals.

Back through the mirror again, what does it mean for adult humans to smell, to perceive chemical signals? It is not a cognitive sense, or should we say a ‘cortical sense’. Smell is different in the way it uses a cortex, the perceptual-processor that creates an experience in our minds. For smell, the ‘processor’ is the limbic system itself, a beta-brain that runs inside, underneath, or within our more advanced human brains. This limbic system-chemical signal interaction is much more akin to the way a plant “sees” a sunset than a human. And so, to say that an embryo can smell, is less of a stretch than to say that it can see.

It makes matters more complex, however, when the chemical environment of the organism in utero actually affects its adult behavior. But because smell is a learned perception – an emergence of episodic memory – the osmic sensorium that we experience today and ultimately the way we respond to it, is predicated upon the very primitive origins of our ontological journey.

Study shows embryos can learn

Pond snails are able to sense chemicals released by their predators whilst they are still embryos in the egg and alter their behaviour accordingly, according to new research at Aberystwyth University and the University of Exeter and Plymouth University

When snails are exposed to predator smell during this very early developmental stage, they are better able to avoid predatory fish once they hatch...

The ability to respond to potential predators while still in the egg may be extremely important in allowing young vulnerable snails to survive.

Saturday, April 8, 2017

Music, Maps, and Categorgonzola

(highlighting my own personal favorite genre-neighborhood, the drum n bass part of town)

A Dizzying Infographic Traipses Through 146 Years of Music

A polymathic Belgian architect named Kwinten Crauwels has created a map worthy of praise for anyone who stays up at night thinking about how to articulate vast networks of cultural products.

The Music Map is an “interactive infographic that maps the definitions, relationships, and sub-genres of the last 146 years of pop music.

 It’s formally called “Genealogy and History of Popular Music Genres from Origin till Present (1870-2016)” and it’s creator certainly echoes my own struggles to organize the language of smell:

“You can never create the ultimate genre map—there is no such thing, because it’s a sociological reality, not a scientific one,” Crauwels says. “But you can at least create a very good approximation, so people can learn more.” He’s right; Crauwels has built a chart that’s actually chart-worthy.

On Vague Notions of Accuracy
-About the confusion matrix, a great starting point for anyone who is trying to organize things, but is ultimately doomed to failure.

Wednesday, April 5, 2017

You Are Never Gonna Bereave This

‘the sickly sweet smell of rotting flesh’-scented bodywash

Clarification: Scientists are not looking for the “smell of death”, but for the unique profile of molecules specific to decomposing humans when compared to other similar animals.

First of all – who cares? Forensic anthropologists care, because they want to help find dead human bodies in places populated by so many other dead critters. The wildfires in California are an example. With so many dead things there, how do we find the humans? Dogs can be trained (just like people, let Avery Gilbert give you a mouthful on that note) to recognize trace amounts of one particular chemical, or a signature profile, regardless of whether it is part of a much larger bouquet. If we could find the difference between dead human bodies and others, we could better inform our search.

Second thing – what’s the difference between “the smell of death” and the ‘human smell of death’ used in the headline above? Not much. This is certain because we already know “the smell of death”, and it’s called Cadaverine.

It’s got a lot to do with Putrescine, which is another part of “the smell of death” (as well as the smell of semen). Unfortunately, or fortunately, I cannot smell it; I’m anosmic; so I can’t be trusted. I’ll continue nonetheless. Cadaverine is described as the sickly sweet smell of rotting flesh, and you probably smell it more than you think (Exit 14 on the New Jersey Turnpike anyone?). How I wonder what dead bodies “really” smell like, because I am noseblind to one of its major constituents, but I will tell you this: On a midsummer afternoon, at a formal event like a wedding or church, where everyone is freshly-showered yet wafting personal microbiome clouds in competition with their carefully-crafted fragrance-enhancing products, Cadaverine trickles through the air.

Yes, a sheen of it covers these warm bodies, a fine layer of pulverized, rotting flesh, spread to every square inch by perhaps day-, perhaps week-old washcloths. I call it “dirty washcloth”, but I’d rather not. Sometimes, or in a strange animalistic way, it can actually smells good.

Oh, would you look at that, the Bvlgari Soir that’s been sitting on a test-strip on my desk for the past six days has been almost all dissipated, through the stages from complex aroma, to base notes, to one particular note, something musky, to this now lone Cadaverine. Even your cologne smells like dead people.

Post Script:
In this study, a validated method using a thermal desorber combined with a gas chromatograph coupled to mass spectrometry was used to identify the volatile organic compounds released during decomposition of 6 human and 26 animal remains in a laboratory environment during a period of 6 months. 452 compounds were identified. Among them a human specific marker was sought using principle component analysis. We found a combination of 8 compounds (ethyl propionate, propyl propionate, propyl butyrate, ethyl pentanoate, pyridine, diethyl disulfide, methyl(methylthio)ethyl disulfide and 3-methylthio-1-propanol) that led to the distinction of human and pig remains from other animal remains. Furthermore, it was possible to separate the pig remains from human remains based on 5 esters (3-methylbutyl pentanoate, 3-methylbutyl 3-methylbutyrate, 3-methylbutyl 2-methylbutyrate, butyl pentanoate and propyl hexanoate). Further research in the field with full bodies has to corroborate these results and search for one or more human specific markers. These markers would allow a more efficiently training of cadaver dogs or portable detection devices could be developed.

Rosier E, Loix S, Develter W, Van de Voorde W, Tytgat J, Cuypers E (2015) The Search for a Volatile Human Specific Marker in the Decomposition Process. PLoS ONE 10(9): e0137341. DOI: 10.1371/journal.pone.0137341

Post Post Script:
Sensory Psychologist Avery Gilbert features the “I Smell Dead People” installments on his blog First Nerve.