> yawning is not simply an intensified breath but a distinct cardiorespiratory manoeuvre that reorganizes neurofluid flow
Brilliant, I'll use that next time I yawn somewhere inappropriately.
cyanydeez 58 minutes ago [-]
I've just reorganized my neurofluid flow, that's how I feel about this.
loire280 55 minutes ago [-]
Reminds me of a recent finding that attention lapses in a sleep-deprived brain correlate with flushing of cerebrospinal fluid (almost a garbage collection pause).
The contagious nature of yawning is so weird. It has to be evolutionarily advantageous because it's so wide spread, but it's also non-obvious.
nickthegreek 3 hours ago [-]
I literally yawned as I clicked on this article from my RSS reader. The contagious nature at the mere idea of a yawn is wild.
embedding-shape 2 hours ago [-]
I yawned as I read the title on the frontpage. Smiled a bit when I read the rest of the comments. Contagious beyond physical proximity sure is wild.
carlmr 2 hours ago [-]
I yawned when I read your comment.
davidw 3 hours ago [-]
Me too but I also wonder how much I'm influenced by knowing that that is supposed to happen.
InsideOutSanta 59 minutes ago [-]
I want to yawn, but I'm fighting it. Not all heros wear capes.
B-Con 2 hours ago [-]
Yawing seems like it must be adventurous, the contagious part not so much.
Even the mention of a yawn can trigger it.
Perhaps we are almost always in a state of needing a yawn, but the trigger is seldom met, and seeing or hearing about it is enough to make our brain go "oh yeah I forgot about that".
Perhaps yawning is actually underdeveloped and an ideal human would yawn at regular intervals without any prompting.
Terr_ 11 minutes ago [-]
I assumed it was a kind of warning system: "Another member of the tribe detected impairment/fatigue and took measures to become more alert, perhaps you should raise alertness also."
clscott 3 hours ago [-]
A trait doesn’t have to be advantageous to persist just non-detrimental.
rtkwe 2 hours ago [-]
Yeah that's (to me) a more accurate framing, also evolution is bad at revisions so even if there are minor disadvantages to a setup so long as it's not affecting your ability to have and raise kids it's basically completely absent as far as evolution is concerned. For example there are some wild inefficiencies in body layout left over from fish body patterns where the nerve from the brain to the voice box wraps down around your aortic arch because the relative position of the throat, brain, and heart were very different in fish so the path it took then was more direct. It happens in humans and most hilariously in giraffes where it goes all the day down their enormous necks.
samus 7 minutes ago [-]
[delayed]
cyanydeez 57 minutes ago [-]
If Giraffe could speak, would they then be perceptibly delayed compared to humans?
seszett 44 minutes ago [-]
Well they make no sound, so that might be related. Maybe it's just really impossible because of this.
frisbm 2 hours ago [-]
and not even that, I'd narrow it further to not detrimental before and during the prime reproductive periods of a species. After that period, detrimental traits are totally fair game and more dependent on technology, culture, and family care dynamics. Heart disease later in life caused by genetic predisposition to high cholesterol isn't something people generally select for or against in a partner, but its effects happen later in life well after people have children so it passes on.
toasterlovin 47 minutes ago [-]
> Heart disease later in life caused by genetic predisposition to high cholesterol isn't something people generally select for or against in a partner, but its effects happen later in life well after people have children so it passes on.
That depends. It can still affect genetic fitness if it affects an individual's ability to confer benefits on their descendants. Of note: most of the most wealthy and influential people in our society are beyond their reproductive years (not technically true for men, but mostly true in practice).
samus 6 minutes ago [-]
[delayed]
EA-3167 2 hours ago [-]
They can be detrimental too, especially if they're linked to beneficial traits. The test is ultimately whether or not the harm done is sufficiently disadvantageous that it interferes with reproductive fitness. Baldness is arguably detrimental, but it's linked to a bunch of recessive genes that function in other ways, and it doesn't impact us until we're likely to have already reproduced.
That's a simplification, but you get the idea.
TheGRS 2 hours ago [-]
Peacocks with their giant tail feathers are my favorite example. They make flying really difficult, but they make attracting female mates much easier. The reproduction need wins.
awesome_dude 58 minutes ago [-]
And that, my friends, is why I bought a Pontiac...
CGMthrowaway 2 hours ago [-]
It is detrimental though. It is socially impolite to yawn in public.
Edit: why am I being downvoted for this?
bc569a80a344f9c 2 hours ago [-]
Even if yawning in public affected sexual fitness: how long has it been socially impolite to yawn in public? Evolution takes a rather long time in species with long reproductive cycles. Almost all mammals yawn, it would take significant genetic changes to breed that out of us. That doesn't happen overnight.
CGMthrowaway 1 hours ago [-]
400-500 years minimum (15-20 generations), although point taken
JoshTriplett 55 minutes ago [-]
> It is socially impolite to yawn in public.
No, it isn't. It can be socially impolite to yawn unexcused, when someone is talking to you, as it has come to be interpreted as boredom rather than tiredness or similar. But it isn't inherently impolite to, for instance, yawn when walking down the street, or in a setting where someone isn't talking to you.
avazhi 27 minutes ago [-]
> why am I being downvoted for this?
Because you don’t know what detrimental means in this context and clearly don’t understand evolutionary timescales?
victorbjorklund 2 hours ago [-]
I wonder if that has always been the case or if it is a modern thing (modern in the sense of our evolutionary history).
frisbm 2 hours ago [-]
is it so detrimental that it leads to a person never finding a mate and reproducing? Maybe for a totally extreme outlier, but probably not
CGMthrowaway 2 hours ago [-]
Is that the right criteria? A trait must be completely, 100% disqualifying as a mate or else it sticks around?
Our ancestors used to have tails. We no longer have tails. Plenty of people wear artificial tails today and get laid, it's not a 100% disqualifying trait
vizzier 2 hours ago [-]
Natural selection doesn't require 100% disqualifying, it just needs a slight preference and a shit load of time.
CGMthrowaway 1 hours ago [-]
Yes that is more along the lines I was thinking
kace91 1 hours ago [-]
>Plenty of people wear artificial tails today and get laid
…Do they? What did I miss?
59 minutes ago [-]
2 hours ago [-]
HPsquared 2 hours ago [-]
It's a bit like laughing. Synchronise the mood of the group. I assume other mammals have contagious yawns too?
wjb3 40 minutes ago [-]
I think you're onto something here. Does anyone know if there are examples of very non-social species yawning (i.e., something that has a brief mating period with no prolonged pair bonding, and then it lays eggs and takes off)?
wjb3 36 minutes ago [-]
So, I tried to track down an answer. And, apparently, there’s currently no well-replicated study showing true contagious yawning in a species that is otherwise non-social and non-bonding.
It is strange how well yawning is conserved, even as far back as in reptiles, since it doesn't really seem to do anything.
kgwxd 3 hours ago [-]
Just about all our behaviors are contagious. Scratching, deep breath, emotion, looking in a certain direction, sudden alertness. If yawning were different, that would be weird.
nickthegreek 2 hours ago [-]
Most of those can also be done consciously though. Yawning is different. It is more inline with flatulence, crying, or vomiting. Actions that are in many ways, outside of our direct control.
_factor 58 minutes ago [-]
I can yawn on command continuously every few seconds just by thinking about how it feels.
kobalsky 1 hours ago [-]
I can yawn on command. Rumbling my ears and edging swallowing it triggers a yawn 100% of the time
There was an article posted recently about a new discovery around CSF flows during sleep too. It sounds like yawning causes similar flows, which could maybe explain why you yawn more when tired? It could be a compensation mechanism to provide a bit of the same effect you normally get when sleeping.
You know how yawning is also a social function, and seeing someone yawn makes you yawn?
I just got forced into a good neurofluid flow reorganization session just by reading the title.
> “Each individual seems to have what looks like an individual yawning signature”
I’m looking forward to “yawn to unlock”.
Also, what’s the deal with that article image?
16 minutes ago [-]
tetris11 1 hours ago [-]
> If an animal is drowsy or bored, it will be less alert than when fully awake and less prepared to spring into action. "Contagious" yawning could be an instinctual signal between group members to stay alert.
> Anecdotal evidence suggests that yawning helps increase a person's alertness.
> Paratroopers have been noted to yawn during the moments before
they exit their aircraft.
Brilliant, I'll use that next time I yawn somewhere inappropriately.
https://news.ycombinator.com/item?id=45771636
Even the mention of a yawn can trigger it.
Perhaps we are almost always in a state of needing a yawn, but the trigger is seldom met, and seeing or hearing about it is enough to make our brain go "oh yeah I forgot about that".
Perhaps yawning is actually underdeveloped and an ideal human would yawn at regular intervals without any prompting.
That depends. It can still affect genetic fitness if it affects an individual's ability to confer benefits on their descendants. Of note: most of the most wealthy and influential people in our society are beyond their reproductive years (not technically true for men, but mostly true in practice).
That's a simplification, but you get the idea.
Edit: why am I being downvoted for this?
No, it isn't. It can be socially impolite to yawn unexcused, when someone is talking to you, as it has come to be interpreted as boredom rather than tiredness or similar. But it isn't inherently impolite to, for instance, yawn when walking down the street, or in a setting where someone isn't talking to you.
Because you don’t know what detrimental means in this context and clearly don’t understand evolutionary timescales?
Our ancestors used to have tails. We no longer have tails. Plenty of people wear artificial tails today and get laid, it's not a 100% disqualifying trait
…Do they? What did I miss?
Strangely, dogs sneeze to show deference.
https://news.ycombinator.com/item?id=45771636
Is that the paper in question?
I’m looking forward to “yawn to unlock”.
Also, what’s the deal with that article image?
> Anecdotal evidence suggests that yawning helps increase a person's alertness.
> Paratroopers have been noted to yawn during the moments before they exit their aircraft.
https://en.wikipedia.org/wiki/Yawn
happens to me a lot when i am on shrooms too