Categorgonzola

A perennial topic on this weblog is the categorization of smells. Today I'm looking at a study from 2011 that looks at common features that group smells together. One of the common denominators is hedonics, or pleasantness vs non-pleasantness.

It always makes me pause to think about this, because it seems that people can never really agree on what makes a smell good or bad, and yet the hedonic dimension is the only one that keeps coming back as the primary distinction between odors. I guess that's just the law of large numbers at work, a law which is against natural human cognition.

If you include enough people in your study, the differences between us cancel out and you're left with a fuzzy but recognizable picture of a smell map, which is seen above.

The other common denominator (it’s not a denominator if there’s two, right?) is a dimension the researchers call natural/chemical.

This map is organized as follows: Whereas the pleasantness of an odor can be predicted on the number of carbon atoms per molecule (related to how fast it evaporates), the natural/chemical dimension is predicted by the polarity of the molecules, or how attracted they are to water.

Why? Not so sure. Mention is made to the difference in the olfactory receptors themselves - some are from when we were fish and some are from when we became land animals, so the two may have a different relationship with water (polarity).

For example, odorants are dispersed more slowly in the water. Also, smellable molecules to fish don’t have to be volatile organic compounds, because for a fish, the air itself is already a liquid. So fish detect water soluble molecules whereas humans detect airborne molecules.

Actually, now that I look at the ‘natural’ part of the map, I realize that none of those things exist underwater, right? Burnt? Nope. Moldy? Although mold is always associated with moisture, it doesn’t grow underwater. And Earthy? Kind of the opposite of water.

Natural - Burnt, Smoky, Nutty, Woody, Resinous, Musty, Earthy, Moldy, Almond, Popcorn, Peanut Butter, Oily, Fatty, Warm, Dry, Powdery

Chemical - Etherish, Anaesthetic, Chemical, Medicinal, Disinfectant, Carbolic, Sharp, Pungent, Acid, Gasoline, Solvent, Cook, Cooling, Cleaning Fluid, Paint, Camphor

Good - Fragrant, Sweet, Perfumery, Floral, Light, Aromatic, Cool, Cooling, Fruity, Citrus, Rose

Bad - Sharp, Pungent, Acid, Heavy, Musty, Earthy, Moldy, Burnt, Smoky, Oily, Fatty, Sour, Vinegar

-image source: link

Notes:

In search of the structure of human olfactory space. A. A. Koulakov, B. E. Kolterman, A. G. Enikolopov, D. Rinberg. Front. Syst. Neurosci. 5, 65 (2011).

doi: 10.3389/fnsys.2011.00065

The Language of Color

Ancestral state reconstructions on consensus tree. Haynie HJ, Bowern C (2016) Phylogenetic approach to the evolution of color term systems. Proc Natl Acad Sci USA 113(48):13666-13671. link

Biology, meet philology: First application of phylogenetic evolutionary framework to color naming

Dec 2016, phys.org

I have been an art teacher for ten years, and always took notice of what happened to the box of colored pencils in my classroom. In September, it had all the colors, and as the year went on, a distinct pattern would emerge. The red pencils were always the first to go, and by the end of the year, the only things left were brown, orange, yellow. It always made me wonder if we each had our own subjective color preferences, or if we were hardwired for some over others.

So, I’m very excited to read this article on color evolution. This has been a recurring topic on Network Address, the companion blog to Limbic Signal. This work in particular looks at the way that color-names enter or drop-out of a language. In the image above, we see that everyone has names for the black and white, and red comes next. After that, green and yellow vie to be in our mouths. The authors explain that there tends to be names first for things that are maximally distinct. Hence black and white first. Why does red come next? There’s plenty of reasons, some simple, some confusing, but we know that in just about every culture, every situation, red comes next – or first, depending on whether you consider black and white as colors.

I will take a contradictory stance to something one of the study authors states. Prof. Claire Bowern says, “humans aren't very good at smelling (compared to hearing or seeing), so it's not surprising that we don't have a lot of smell-based vocabulary.”

Actually, that's not the reason. Instead, we don't have names for smells because the language-parts and the smell-parts of our brains are so separate, and because of reasons that took me an entire book to enumerate. (See Hidden Scents.)

Later on, however, she drops a shiny gem while making a point about the lifelike behaviors of the language of color:

"It's uncontroversial that language changes; it's also uncontroversial that languages aren't organisms. The point is that from Darwin on, language and biology have had a long history of cross-pollination and co-inspiration."

This is one of the most beautiful discoveries I came across in working on Hidden Scents, which is that the very concept of evolution, of natural selection, developed by Darwin, was based on the taxonomy of languages across the world. Language may not be alive, but our cultures are, and for some of us, we can say that by extension the products of those cultures are also alive. Regardless, it is hard to deny the influence that such potentially ‘inorganic entities’ have on our concepts of all things organic. In other words, we assigned what we now know as the process of biological evolution to language before we understood it regarding living organisms.

I’m just going to requote this whole section from my other blog, it’s good stuff so why not:

Darwin:

“It may be worthwhile to illustrate this view of classification, by taking the case of languages. If we possessed a perfect pedigree of mankind, a genealogical arrangement of the races of man would afford the best classification of the various languages now spoken throughout the world... The various degrees of difference in the languages from the same stock, would have to be expressed by groups subordinate to groups; but the proper or even only possible arrangement would still be genealogical…”

Darwin, C. R. 1859. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. [1st edition]

[page] 422 CLASSIFICATION. CHAP. XIII. [link] via Steven Pinker - The Genius of Charles Darwin: The Uncut Interviews. BBC, 2008

POST SCRIPT

Cultural Evolution of Basic Color Terms

Network Address, 2012

Seeing Red

Network Address, 2013

Color-Brained

Network Address, 2014

Natural Intelligence X Artificial Intelligence
Network Address, 2012