Information Concentration Gradient Navigation

 

'Walk this way': Model explains how ants create trails to multiple food sources

Nov 2024, phys.org

https://phys.org/news/2024-11-ants-trails-multiple-food-sources.html

"If an ant has access to multiple food sources from its nest, it will initially make multiple trails to each of the sources."

Using computational simulations of ants searching for food, stochastic modeling and a system of partial-differential equations, and two subpopulations of foragers who wander around in search of food and returners who always return directly to the nest after finding food, the researchers observed that ants will selectively travel to the food source that is the shortest distance from its nest in an environment with multiple sources.

They found this collective behavior resides in the fundamental pheromone concentration gradient, where the returning ants would secrete less pheromones depending on how close the food source was to the nest, whereas more pheromones created a stronger scent.

via Florida State University Institute of Molecular Biophysics and Department of Mathematics and Statistics at Cleveland State University: Sean Hartman et al, Walk this way: modeling foraging ant dynamics in multiple food source environments, Journal of Mathematical Biology (2024). DOI: 10.1007/s00285-024-02136-2

https://dx.doi.org/10.1007/s00285-024-02136-2

Image credit: AI Art - Black Hole - 2025

The brain's processing paradox: Study quantifies the speed of human thought

Dec 2024,  phys.org

https://medicalxpress.com/news/2024-12-brain-paradox-quantifies-human-thought.html

This is pertinent to the article but such an important statement for understanding the brain, the body, evolution and of course chemosensation as the origin of brains:

They applied techniques from the field of information theory to a vast amount of scientific literature on human behaviors such as reading and writing, playing video games, and solving Rubik's Cubes, and quantified the speed of human thought at 10 bits per second. However, our bodies' sensory systems gather data about our environments at a rate of a trillion bits per second, which is 100 billion times faster than our thought processes.

But this question: Why does the brain process one thought at a time rather than many in parallel the way our sensory systems do?

"Human thinking can be seen as a form of navigation through a space of abstract concepts." Research suggests that the earliest creatures with a nervous system used their brains primarily for navigation, to move toward food and away from predators. If our brains evolved from these simple systems to follow paths, it would make sense that we can only follow one "path" of thought at a time.

via California Institute of Technology: Jieyu Zheng and Markus Meister. The Unbearable Slowness of Being: Why do we live at 10 bits/s?, Neuron (2024). DOI: 10.1016/j.neuron.2024.11.008.

https://dx.doi.org/10.1016/j.neuron.2024.11.008

Statistical Sampling of the Olfactory Environment

It appears that a discovery has been made, all over the place and all at once, about how the mixture of air changes the way smells are perceived. 

It's not at all unusual that multiple simultaneous discoveries have appeared, in fact it's the rule not the exception in science. The articles below all seem to have discovered that a turbulent cloud of odor molecules smells different than what I'll call a more homogenous, slow-moving cloud. 

Based on the above image, see the great CFD video illustration of air movement here.

It's like you're getting a more representative sample. When smells occur in your environment, they move as streams and plumes, picture wisps of smoke. If you're about to "sample" a piece of data, it means you're about inhale a cubic foot of air. What are the chances the amount of molecules you need to register an odor will be in that cubic foot? If you were to snapshot the cube before you inhale, you could imagine the airsteams of the odor you're looking for, let's say the scent of a female moth pheromone, twirling through the cube. But if you shook up all the air around you, to get into your breathing space some of the airstreams from outside the space, then you get more chance that the target molecule will make it into your "sample" sniff. From a statistical point of view it does make sense - you're squeezing more airstreams into a smaller space and time.

Study suggests that 'Jedi' rodents remotely move matter using sound to enhance their sense of smell

Oct 2024, phys.org

https://phys.org/news/2024-10-jedi-rodents-remotely.html

Surprise! "This phenomenon has never been observed before, or I believe even suspected, in any animal"

(This is from a bioacoustics researcher btw.)

Scientists have debated the purpose of the ultrasonic vocalizations (USVs) produced by rodents since the discovery of these sounds in the 1950s. This new paper suggests they do it to shake up their surroundings in ways that influence how inhaled particles enter their noses, suggesting that rodents use sound to enhance their sense of smell.

"They're creating new pathways of information by manipulating their environment and controlling the molecular interactions of particles around them."

Rodents explore their environment by stroking surfaces with their whiskers, visually scanning, and incessantly sniffing. Mercado discovered that studies on vocalizations that also monitored sniffing showed that rodents immediately sniffed after producing each USV.

"That could be a coincidence, or it might suggest the two are functionally related," he says. "I knew that techniques for using ultrasound to manipulate particles are used in the field of vibroacoustics and thought immediately that might also work for animals."

Vibroacoustics, or artificially produced ultrasonic vibrations, cause airborne particles to cluster, leading Mercado to suggest that rodents are using USVs to create odor clusters enhancing the reception of pheromones (chemical signals), thus making it easier for the vocalizer to detect and identify friends, strangers, and competitors.

via University at Buffalo: Eduardo Mercado et al, Do rodents smell with sound?, Neuroscience & Biobehavioral Reviews (2024). DOI: 10.1016/j.neubiorev.2024.105908. 

https://dx.doi.org/10.1016/j.neubiorev.2024.105908

Study uncovers how silkworm moth's odor detection may improve robotics

Oct 2024, phys.org

https://techxplore.com/news/2024-10-uncovers-silkworm-moth-odor-robotics.html

They employed high-speed photogrammetry to computationally analyze the aerodynamic consequences of wing motions of the silkworm moth (Bombyx mori).

This insect that no longer flies due to domestication, but does flap its wings when they detect pheromones.

One of the key findings of the study was that B. mori samples the pheromone selectively from the front. The moth scans the space by rotating its body while fanning to locate the pheromone sources. The directional sampling of the pheromone molecules is particularly helpful when searching for an odor source since the moth can determine the direction of the odor plume upon the detection of the pheromone.

This could lead to advancements in robotic odor source localization technologies, where drones equipped with insect antennae for odor detection carefully adjust their orientation and the configuration of their propellers and odor sensors to optimize detection capabilities.

via Chiba University Graduate School of Engineering: Olfactory sampling volume for pheromone capture by wing fanning of silkworm moth: a simulation-based study, Scientific Reports (2024). DOI: 10.1038/s41598-024-67966-y

https://dx.doi.org/10.1038/s41598-024-67966-y

People with no sense of smell found to have abnormal breathing patterns

Oct 2024, phys.org

https://medicalxpress.com/news/2024-10-people-abnormal-patterns.html

The researchers sought to address anecdotal accounts of people who could not smell and began "breathing funny" after contracting COVID-19.

The research team recruited 52 volunteers, 21 of whom were suffering from anosmia, and fitted them with a breathing monitor for 24 hours.

The research team found that those volunteers with anosmia did have slightly different than normal breathing patterns. People without the condition, they note, have small inhalation peaks, which prior research suggests coincides with a suspected change in smell. People without the ability to smell had no such peaks.

via The Azrieli National Institute for Human Brain Imaging and Research: Lior Gorodisky et al, Humans without a sense of smell breathe differently, Nature Communications (2024). DOI: 10.1038/s41467-024-52650-6

https://dx.doi.org/10.1038/s41467-024-52650-6

White Smell Machine

[compulsory image]

Another piece of news sitting in my to-post box for way too long:

Brothers Lav Varshney with the University of Illinois, and Kush Varshney, with IBM's Thomas J. Watson Research Center have taken the idea of White Smell further by creating a mathematical model that could be used to create a working 'olfactory white machine' which by using an olfactory ananlog to White Noise could render a smell unsmellable.

Their white smell machine could be used to improve indoor air quality, or by the food industry to cancel bad smells.

Age of Approximation

Screenshot from Iain McGilchrist called the Divided Brain on RSA Animate and TED.

“The Age of Enlightenment is Dead.” Thank you, Mr. Danny Hillis, for putting this in writing, and in the new MIT Journal of Design and Science no less.

Mr. Hillis makes the case, in a brief but very coherent treatise, that science is due for an update. In fact, it is not just science, but the very idea of human endeavor and progress. I recall the TED talk given by Iain McGilchrist called the Divided Brain. (This guy is author of The Master and His Emissary: The Divided Brain and the Making of the Western World, 2009). In his talk, he describes how the brain is split in two; the truth is more nuanced than that, and this is the point of the talk in fact. He goes on – there are two metaphorical sides, and they each do two different things, and the reason we tend to be right-handed is because the corresponding side of our brain is for active, intentional manipulation. And on – throughout history the pendulum swings, and one day we may regard the right side as the “right” side (because the Age of Enlightenment made us value the left side so much).

In the art classroom, I repeat these ideas, and ask them what the world would be like if everyone was “right-brained,” or artistically minded. Imagine if everyone was an artist, and nobody a scientist, all emotion and flight-of-fancy, and no bridges, tunnels, infrastructure, economic policy, institutions of higher learning, no numbers, no logic, and nothing to separate sense from nonsense. Crazy.

Then again, I can sort of imagine a world where artificial intelligence does all that stuff for us, so we can do more human things, more messy, emotional, intuitive things. I highly doubt this is what Mr. Hillis is talking about in his essay, but I’m quite excited nonetheless that he’s talking, period. He says right here:

“As our technological and institutional creations have become more complex, our relationship to them has changed. We now relate to them as we once related to nature. Instead of being masters of our creations, we have learned to bargain with them, cajoling and guiding them in the general direction of our goals. We have built our own jungle, and it has a life of its own.”

The Enlightenment is Dead, Long Live the Entanglement

Danny Hillis, MIT Journal of Design and Science, March 2016

Post Script:

What the hell does all this have to do with the Language of Smell?

A primary objective of Hidden Scents is to present the idea that after the wave of Big Data crashes on the shores of human civilization we will have entered a new era, one in which certainty itself is no longer valued in the way it once was. We already see this today, when we ask what it is that separates us from our imminent AI overlords. Humans have intuition, something an algorithm can never have, by its nature. Humans can do this thing called “messy thinking,” or fuzzy thinking, or half-thinking. This is what leads us to make novel discoveries and connections and to be creative in general. This is what makes us not computers. And in its uncanny way, this kind of mental activity is at the core of olfaction. To smell something is to navigate a sea of data too large to fully comprehend. In this sea, one can approximate, but never ascertain. (The source of a particular smell is only verified by one of the other senses, like when you actually find that dead mouse under the fridge.)

So if the Age of the Enlightenment is dead, then perhaps olfaction (and more specifically the language of olfaction) can serve to carve the path ahead.

Well, perhaps you think I’m a bit too right-brained to be writing about such things. Thanks for reading at least.