Thursday, April 11, 2019

The City with No Smells


We all know that air pollution is a real threat, both to ourselves and our planet. And we all know that automobiles and electricity generated by fossil fuels are the major contributors to this pollution, and mostly because they are visible (except that they’re really not visible – the plumes you see exhausting from tailpipes and smokestacks tend to be water vapor; the polluting parts are invisibly microscopic.)

But there's another suspect out there which goes largely ignored, and as it would, because it's largely invisible to us.

We're not talking about cow farts, but cooking grease. To be more scientific, it is called organic aerosols, and it comes from the oils and organic matter that are heated in the process of cooking, and ejected out of the kitchen and into our urban environments.

As science starts to zero-in on atmospheric offenders, the local sources of pollution become more apparent. You will be way more exposed to the particulate matter exhausting from a tailpipe if you're driving right behind one, as opposed to watching it from your apartment window. But you are also more exposed to the organic aerosols exhausted from your local taqueria as you walk around your neighborhood, as compared to a pollution meter stationed on the roof of your 4-story apartment building.

So although global pollution is a problem for sure, local pollution is a problem even moreso, and one that needs to be managed in order to raise the quality of life for ever-increasing urban populations.

Thing is, although organic aerosols may be invisible, they are smellable. And although there are plenty of examples of restaurants "polluting" our urban environment with rancid reminders of why Yelp is still in business, there are just as many examples of locale-defining odor profiles marking your travels about your home neighborhood, or your favorite tourist destination.

Popcorn at the movie theater* is an obvious example, but there are plenty more of these olfactory advertisements to enjoy, and which even help to define a neighborhood. It's interesting to think of a historic preservation society that adds to their list of cornices and cobblestones a particular plume that really defines a place – a specific combination of cultural cuisine that can only be found in that little nook where the Polish krautmakers and Indian currystirrers all live together.

That being said, it’s not hard to imagine a future where everything that smells is bad for you and hence ridden. A city with no smells. Very healthy, very uninspiring.

*I was recently informed by a friend that, to him, "popcorn smells like vomit," which does make sense IF the butter is rancid, because isovaleric acid is a primary constituent of rancid butter, and is the smell of vomit and fermented feet sweat.

Notes:
Nov 2018, phys.org

Post Script:
Good smells aside, when you roast things like nuts, popcorn or coffee, some of the compounds released are called diacetyls, which can cause serious respiratory problems for workers exposed to it in high amount.


Thursday, March 21, 2019

Your Mother



Word.

Somewhere in England they are now programming smoke alarms with your mother's voice instead of an ear piercing siren, because it gets you out of bed quicker. The precious seconds saved could also save lives.

The reason the sound of your mother's voice can turn on your inner alarm faster than a fog horn, has a lot to do with our nature as social creatures, and of course, our limbic systems.

The limbic system is the part of us that takes flight in a dangerous situation. It is a brain inside our brain, and if it had a brain inside it, that would probably be the amygdala; I'm sure you've heard of it. It also holds the hippocampus, also known as the memory bank.

The limbic system operates beyond our conscious control. It has to, because it's a big part of what keeps us alive before we even become "conscious." It learns from its environment, and responds accordingly. A major part of that environment is the people around us.

Our status as social animals makes us very sensitive to the people around us, and especially those who take care of us, and especially even more those who take care of us when we're young.

This is because our limbic system is, shall we say, very open to suggestion when we're young. It's kind of like a blank slate of a book, or an instruction manual, where every word that's written starts out really big, and gets smaller and smaller as we age.

And who is one of the first people to write in this book? Your mother. She codes her voice so deep into your autonomic nervous system that the sound of it can activate your limbs faster than flash of lightning.

So it only makes sense that if we are looking for a shortcut to the body-control-system, this would be it.


Notes
Oct 2018, BBC

Robet Sapolski's Stanford lectures in Human Behavioral Genetics are a great place to learn about this kind of thing; he is a skilled and engaging lecturer.


Post Script
Consider this idea in light of the developments we see today in robotics, or in any instance of digitally-mediated human assistance. Robots that take care of the elderly in the absence of their progeny, or who take care of people of reproductive age in the absence of a mate. The limbic system is a powerful thing, and it will certainly be exploited.


Post Post Script
Elon Musk did a surprisingly interesting job of describing all ^this in his infamous interview on the Joe Rogan show.


Post Post Post
Amygdalic is a word, but it doesn't do what you want it to in this context. It comes from chemistry and it means made of almonds, or rather the amygdalin contained therein. And now you got me started, almonds do also contain cyanide, but not enough to kill you, you robust biological specimen! If you ever had a rotten almond, you can pretend that's the cyanide in your mouth. Not totally sure about that, but there is another species of almond, actually called the bitter almond, that has more cyanide in it, and is also the almond used to make almond fragrance. The amygdala got its name because it is shaped like an almond.


Wednesday, March 20, 2019

Get Minty




Hanging out with some friends the other night, and as bedtime rolls around, I hear my friend say to her son, "Come on, time to get minty."

I had never heard this before, but I knew exactly what it meant. I was excited at the novelty of it, but also that it makes brushing your teeth sound like way more fun than "brushing your teeth."

I was also set wondering why I had never heard this before; it makes so much sense. But my next thought is the one that took hold – why is toothpaste minty?

Today I'm here to tell you why toothpaste is minty; there’s two reasons. One of them makes sense and the other does not.

The easy answer for why toothpaste to this day remains minted lies in the trigeminal properties of mint. The trigeminal sense is not so much a sixth sense, but more like 5 1/2. When things are sensed as spicy-hot or minty-cool, that is the trigeminal sense being activated. This effect creates a habit cycle by making you think your breath is fresh after brushing because your mouth feels cooler.

That's a good reason. But there are other things that produce trigeminal effects. Jalapeno peppers would make a good toothpaste on this account. (Why does it have to be cool?) Then there's cardamom seeds. And fennel. Why isn't toothpaste made of liquorice?

Coincidence, that's why. Mint just happened to be the flavor of the toothpaste to land on Claude Hopkins doorstep. He is advertising's first master manipulator, and the man responsible for the reason we brush out teeth.

I know this might sound crazy, but prior to Pepsodent in the 1900's, people did not brush their teeth. Crazy. We had to be duped into it by a marketing campaign. And dupe he did – 100 years later, here we are, still getting minty before bedtime, every night.

It is unclear as to whether Hopkins knew the power of trigeminal effects in creating a habitual feedback loop. But he definitely understood the concept of the loop.

When his client came to him for help selling his new tooth-paste product, Hopkins spent hours and hours reading about dentistry and oral hygiene, until one small illustration struck him.

A page in the book indicated that there is a film that forms on the surface of your teeth, and all over your mouth. In the dental textbook it's called mucin plaque, but he called it "the film." The film is always there, and it's always been there. But Hopkins was a mental manipulator maximus.

He transformed that factoid thus:

You – run your tongue over your teeth, you feel that? That's a film of gross nasty schmutz that accumulates on your teeth every day. It's gross, and it also makes your breath smell. You like that filthy mouth film? No, no you don't. So why don't you get yourself a tube of Pepsodent, and scrub it right off. There. Feel that mint-flavored freshness? There, all better.

Feeling the film on your teeth was the cue, and having a fresh mouth was the reward. These two work together to rewire your brain until we have a habit. For things like nicotine and smoking, the cue is a physiological imbalance, because nicotine is addictive. But for other things that are not drugs, we must create a habitual loop.

Claude Hopkins knew this, and with this knowledge he set a civilization on the path to oral health. The fact that this path was minty fresh was kind of inconsequential. And since we're here talking about this, I should add that in India, where mouth health has been a big deal for much longer than toothpaste, they have a few different approaches. Cardamom, fennel, and fenugreek are sometimes roasted, sometimes candy-coated, but usually chewed after a meal.

Would fennel toothpaste ever take off? I'll keep my eye out the next time I'm in Trader Joe's, or that little Vermont grocery store.

And now for the final reveal, the first Pepsodent wasn’t even made with Mint, it was made with Sassafras (think Root Beer). I will assume this was categorized as “minty.”  I’m also having a fuzzy recollection that Burt’s Bees makes a clove toothpaste?

Notes:
How the history of toothpaste explains why you can’t lose weight
Charles Duhigg for Slate
https://charlesduhigg.com/how-the-history-of-toothpaste-explains-why-you-cant-lose-weight/

Charles Duhigg wrote a book about habit formation, called The Power of Habit. I wrote about Charles's book in my book called Hidden Scents.



Wednesday, February 27, 2019

Spaced Out



Because of its key role in navigation, odor-detection and spatialization go hand-in-hand. A paper from McGill's Department of Psychiatry and the Douglas Mental Health University Institute gives evidence to support this relationship.

The hippocampus, which is the central location where spatial memories are "stored," is a key part of the olfactory system. The two – space and smell – are so closely related that they can become difficult to disentangle.

There is a great philosophical essay about the ontogeny of a salamander (see Hosek and Freeman below) in which a creature develops its identity (if questionably-sentient creatures can be said to do so) by way of olfaction. This creature, as with many others, interfaces its environment primarily by smell, especially in the beginnings of its life. The decisions that it makes then are in response to olfactory information, which through iterated reinforcement forms the foundation of its self.

I was so impressed by this idea that I was compelled to write a short essay myself about space, information and dimensionality, as narrated via the odyssey of the Eukaryote evolving through the epochs to its present-day instantiation as a self-aware human. It can be read here.

***
On this relationship between navigation and olfaction, I am reminded of a comment I received more than once when I was first telling folks about my book on smells – "What is it about architects and smells?" I studied both architecture and olfaction, and apparently, I'm not the only one.

That was something I couldn't answer at the time; I had never heard about it. As I began to meet more people involved in an olfactory occupation, be it writing about fragrance or designing olfactory experiences, I did notice a few interdisciplinary architects scattered among them.

Now it occurs to me quite clearly – architects are not experts at navigation so much as spatial perception in general, and specifically on moving through space. Whereas the painter is concerned with the way the eyes move through two dimensions, and the sculptor thinks about eyes moving in 3-D, the architect is concerned with the moving body.

The late architect Michael Graves made this the thrust of his speech as he opened his own School of Public Architecture at New Jersey's Kean University in 2015(ish?) – he told us that in designing a building, the human scale is the only one that matters. The way we feel in a space is the primary criterion when evaluating it. If you think about it, a building is like a body for our body.

***
Architects don’t have to learn much about proprioception, but maybe they should. Proprioception is the feeling that we have of our own bodies, where the parts are, how they're related, what they're doing, and whether we should move them out of the way of danger. (Anybody ever see the hand-smashing phantom limb trick? This is a good example of the power of proprioception.)

As we move through a building, our proprioception recognizes and records not only our own bodies, but the “bigger body” that we're in, whether it’s a building or a backyard. Before there was such a thing as architects or buildings (i.e., before we were human), we used olfaction as a way to calibrate our proprioception, and to navigate this bigger body that we’re in.

It seems I’ve done a pretty good job of navigating myself into the part of this post that I now have no idea how to get out, so I’ll have to leave it there. Architecture and olfaction make a good pair.


Notes:
Oct 2018, phys.org

Louisa Dahmani et al, An intrinsic association between olfactory identification and spatial memory in humans, Nature Communications (2018). DOI: 10.1038/s41467-018-06569-4

Hosek R J & Freeman W J (2001). Osmetic Ontogenesis, or Olfaction Becomes You: The Neurodynamic, Intentional Self and Its Affinities with the Foucaultian/Butlerian Subject. Configurations 9: 509–541.

School of Public Architecture, Kean University

BBC, 2010

Wednesday, February 20, 2019

Olfactory Remains


The picture seen here is taken from a local Arizona news source circa 2014, attached to an article citing the decrease in “migrant deaths” in the Arizona desert at that time. That data was given by Border Patrol. They say most of the deaths are caused by the heat.

But this post isn’t about migrant deaths; it’s about olfactory forensics, using one’s sense of smell to find decomposing bodies.

On the other side of the United States/Mexico border, deaths aren’t from heat, and the bodies are not of migrants. They’re people suspected to have been kidnapped by drug cartels, either for ransom, recruitment, or rivalry. Then there’s the women, who are abducted for trafficking. For whatever tragic fate befell them, their bodies are buried in a clandestine grave.

When farmers and cowboys find bones in the brush, they notify The Searchers of El Fuerte, who investigate suspected burial areas. They dig the earth, and then sniff the air. If they find bodily remains, they take them and send them for DNA testing. If a match is found, they try to inform their relatives.

It may sound primitive, but this is common practice. The human nose is the most powerful device we know of for detecting things that smell. It’s hard to believe, but it does explain why actual humans are hired to smell the fish at large industrial operations to make sure they’re fit for human consumption. It’s also why the fragrance industry employs noses. Shoot, Firmenich, who in 2017 was making 95% of the world’s supply of Hedione (which is in 95% of fragranced products) employ their own truck drivers, custodians, and administrative assistants to assure the quality of their Hedione batches. (This is because so many people have a hard time smelling it; if you’re good at detecting Hedione, no matter what your actual job, you will be asked to sniff batches.)

Back to the bodies. As flesh breaks down, it produces a molecule called Cadaverine, which smells like rotten flesh. (If you’re not sure what that smells like, try driving past exit 14 on the New Jersey Turnpike sometime around August; that should do it.)

Eventually, the cadaverine subsides, leaving other equally offensive odors. There will come a time when a deterred body no longer produces a smell at all. Until then, it is a recognizable indicator.


Notes:
Dec 2018, BBC

Cadaverine has the sickly-sweet smell of rotting flesh
Limbic Signal, 2017
Limbic Signal, 2016
Sensory Psychologist Avery Gilbert features the “I Smell Dead People” installments on his blog First Nerve

Post Script:
Body Farms are places where bodies are buried under all kinds of different conditions, to be examined at various stages of decomposition, for the purpose of aiding forensic anthropology. The information learned on these body farms could be useful for solving potential crimes or missing persons cases.

The Body Farm at the University of Tennessee’s Forensic Anthropology Center



Monday, February 4, 2019

Limbic Fitness and The Aging Brain



We all know that memory function decreases as we age. One of the ways in which this is evidenced is in the correlation between how much our eyes move and the brain activity that comes with it. You see grandpa's eyes skipping around the room, from one face to another, but he isn't recording any of it. (Exaggeration of course, depends how old he is, and his mental capacity.)

It's normal for people of all ages that the more we look at the same thing, the less and less brain activity there is in our memory-forming hippocampus. But in older folks, they can dart their eyes all over the place, and yet generate no information about what they see. No matter how many times they look at a thing, it can remain unfamiliar.

Despite the fact that smell is typically associated with airtight bear-trap memories, we can experience similar diminishing effects with our sense of smell. The relationship is so intimate that our olfactory perception is used to forecast dementia decades in advance.

It is certainly possible that your 60-year old self can be transported 50 years into the past by the mere wisp of familiar a molecule. But your 110-year old self will be less likely to transport so swiftly back to your 60's - the older we get, the less robust the memory-complex formed by each sensation.

This is covered pretty thoroughly in Hidden Scents. Olfaction, the limbic system and our episodic memory form a powerful complex of stored experience. But this system works less and less as we age-out of episodic memory and begin to rely more regularly on semantic memory for our day to day activities.

Episodic memories, i.e., the collection of feelings in your body during a particular episode in your life, are very powerful when recalled. Ironically, they cannot be recalled at will. They must come to us from outside, unlocked by a face, a voice, or a smell. The name of a friend from first grade doesn't do it. The smell of the inside of your first lunchbox, that'll do it.

You're way less likely to be brought to tears at the re-smelling of your first new car (if you were to somehow recreate that, or be so lucky as to be exposed to it later in life). Your dad's first new car - the one you got to ride in when you were 8 - smelling that might get emotional.


Notes:
Oct 2018, phys.org

Zhong-Xu Liu et al, Age-related changes in the relationship between visual exploration and hippocampal activity, Neuropsychologia (2018). DOI: 10.1016/j.neuropsychologia.2018.07.032