The Olfactocracy

No, you don't have to eat your broccoli.

In an experiment that sounds like something we should have done like 70 years ago, we discover that all noses are not created equal. We all smell things differently, perceiving particular odor-features with varying levels of intensity.

I take it back; we didn't have the ability to do this kind of genetics testing 70 years ago. This new experiment showed that of the ~400 genes that control our ~400 different olfactory receptors, the variability is on high. In other words, let's say broccoli has a bunch of different chemicals that make it smell like "broccoli," and that there's a bunch of different receptor-genes that code for those chemicals -- you and I have slightly different versions of those receptors, which make one of us more sensitive to the bad parts of the smell, and maybe even the other of us more sensitive to the good parts.

What you get is one person who doesn't mind eating broccoli, and one of us who gets less ice cream after dinner everytime broccoli's on the menu.

What you also get is an entire sense which lacks in consensus. At the genetic level, what smells good to you won't necessarily smell good to me. So how do we agree?

As groundbreaking a breakthrough as this is, it doesn't even begin to scratch the surface as to how different each of our olfactory experiences are. Each one of us really does live an olfactory world all to ourselves.

We know then that genetics separates us, but it goes even further. Genetics is the hardwiring, but what about the softwiring? If you, for example, were force-fed broccoli while at the same time you're also forced to watch, with your eyes pried open, footage of people trying to peel the foil off a Nutella jar but it rips halfway through, then you might become traumatized by the smell of hot broccoli, and hence highly sensitive, and highly averse to it.

And the reverse can also happen. Don't like Flowerbomb? Wait until you have a few too many romantic encounters with a woman who wears it, and you'll change, you'll see.  That's softwiring. Humans are special because of our neural plasticity, so you can bet we're susceptible to these kinds of changes.

The final note here needs to be on the way we talk about smells. If we all smell a bit different, then how can we really communicate our experiences to each other with any fidelity? 

Image source

Notes:

Genetic variation across the human olfactory receptor repertoire alters odor perception

C. Trimmer, A. Keller, N. R. Murphy, L. L. Snyder, J. R. Willer, M. H. Nagai, N. Katsanis, L. B. Vosshall, H. Matsunami, and J. D. Mainland

PNAS May 7, 2019 116 (19) 9475-9480; first published April 30, 2019

https://doi.org/10.1073/pnas.1804106115

You Will Never Smell My World the Way I Do

Heather Murphy for the New York Times, May 2019

Gene Editing for Behavior Design

Illustrated by Bill Butcher for The Economist

Because ants are social creatures, an ant colony is really a superorganism, making them a valuable model for studying complex biological systems. And because of the way they reproduce, scientists can edit whole colonies in one stroke.

Although ants have 350 odor receptor genes (similar to humans), they also have this thing called a coreceptor gene that every odor gene has to go through to work. Shut that one off, and you shut down the whole system.

And what happens when ants can't smell? They stop talking to other ants, stop doing their job, and they get lost from the group. That's not it though, they also saw changes in brain anatomy, where some sensory substructures didn't grow at all.

Scientists are hoping these studies can help understand how social behavior changes the way neurological disorders like schizophrenia or depression work, and how sensory development in general change the brain.

***
Now, as I stretch on a heavy tangent here, I think about how there are developers on the other side of candy crush and facebook whose job it is to model your behavior and then tweak it to make you stay using the product. Game theory maybe, the science of addiction perhaps? Behavior design, according to this article (an earlier attempt termed it captology). Not sure what we're calling this, but everything from dating websites to the weather channel are using these techniques to keep us tapping into the pleasure centers of our brains and therefore coming back for more. In a distant future, I wonder if we might want to try knocking out the olfactory receptors in people in order to make them more malleable. If we take away people's sense of smell, maybe they will be more easily influenced to do what we want them to do.


Researchers use CRISPR to manipulate social behavior in ants
Aug 2017, phys.org

From two different studies:
Cell, Trible et al: "orco mutagenesis causes loss of antennal lobe glomeruli and impaired social behavior in ants."www.cell.com/cell/fulltext/S0092-8674(17)30772-9 , DOI: 10.1016/j.cell.2017.07.001

Cell, Yan et al: "An engineered orco mutation produces aberrant social behavior and defective neural development in ants"www.cell.com/cell/fulltext/S0092-8674(17)30770-5 , DOI: 10.1016/j.cell.2017.06.051


Post Script:
The Scientists Who Make Apps Addictive, Ian Leslie, Nov 2016, The Economist

good explanation of behavior design in computer programming/software development:

When you get to the end of an episode of “House of Cards” on Netflix, the next episode plays automatically unless you tell it to stop. Your motivation is high, because the last episode has left you eager to know what will happen and you are mentally immersed in the world of the show. The level of difficulty is reduced to zero. Actually, less than zero: it is harder to stop than to carry on. Working on the same principle, the British government now “nudges” people into enrolling into workplace pension schemes, by making it the default option rather than presenting it as a choice.

When motivation is high enough, or a task easy enough, people become responsive to triggers such as the vibration of a phone, Facebook’s red dot, the email from the fashion store featuring a time-limited offer on jumpsuits. The trigger, if it is well designed (or “hot”), finds you at exactly the moment you are most eager to take the action. The most important nine words in behaviour design, says Fogg, are, “Put hot triggers in the path of motivated people.”

...
Unconscious impulses are transformed into social obligations, which compel attention, which is sold for cash.

see also: Addiction by Design, by Natasha Dow Schüll, Princeton 2013