Humans Navigate with Stereo Olfaction | Hacker News Reader

Humans Navigate with Stereo Olfaction

pnas.org

61 pointsedward16 comments

I've thought that you are only breathing through one hole of your nose? Is there still some minor airflow through the other hole to enable stereo olfaction?

If it changes sides over time, and there is minor airflow through the slower side, then yes, that's apparently normal.

If it doesn't change sides over time, or if airflow remains completely blocked through the non-open side throughout every day, look into it further.

(This is not a complete ENT diagnosis flowchart and is not a substitute for an ENT consultation, but has enough detail to survive the basic hypochondria issues of reading Internet medical articles.)

If one of your nostrils is permanently blocked, this is abnormal. Perhaps you want to see an Ear, Nose and Throat specialist?

They were referring to https://en.wikipedia.org/wiki/Nasal_cycle I assume.

Indeed I was. E.g. check this figure: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5053491/figure/...

One nostril has basically no pressure changes while the other one does. How can you smell that way in stereo?

Presumably breathing has no effect on the diffusion of odors from far away to the immediate vicinity of the nostrils. So, diffusion can also take odors from the temporarily-inactive nostril deeper into the sinus.

Interesting, thanks for educating me :)

I think that's a reference to the nasal cycle[1]. I notice it pretty commonly when sleeping, but during waking hours, esp. if I am exercising, both nostrils seem to be unblocked.

1: https://en.wikipedia.org/wiki/Nasal_cycle

If the study is true, and Dr. HN has diagnosed you correctly, you have a nasal version of amblyopia accompanied by attenuated stereonasal perception.

another paper on the topic that does not require subscription, https://journals.plos.org/plosone/article?id=10.1371/journal...

https://sci-hub.tw/https://www.pnas.org/content/early/2020/0...

Obligatory Feynman anecdote (quickest reference story I could find worth linking to, rest of the article is relevant as well)

https://www.salon.com/1999/07/28/smell/

Haha good article. I always smell things before I eat them by default. One interesting thing I noticed is how much smell boosts taste. Some time ago I lost my sense of smell completely and I distinctly remember how the food tastes boring and plain with just texture and sweet and salt making any difference. Smell adds so much to it that I was honestly surprised.

Yes, surely this must be the main use for human smell, to evaluate the safety of food. I remember being laughed at in my youth because I would always sniff a drink before drinking it (these were in my university days so a lot of odd concotions were imbibed). Seemed to me that it gave some very crucial information about what you were to expect!

My father-in-law was a produce inspector for 40+ years. He said that after a while, all he ever did was smell it. He could be walking up to the truck or rail car from across the parking lot and know if it was good or bad.

Another thing working remote can't do (not that I'm fully sold olfaction is stereo)

Digital will not replace most human orientated things until it can directly program the brain.

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