Yawns are weird.
They’re more contagious among family and friends than strangers. Why?
They’re NOT contagious with babies. Why not?
We yawn more when we’re stressed. Since you have to close your eyes when you yawn, wouldn’t that make cave-dudes and -dudettes MORE vulnerable to attack?
Yawns are only HALF-catching: Only about half the people in a group will start to yawn when one person yawns, BUT:
They catch more easily among family, people who feel close, or with people who are more empathetic or compassionate.
So, what I want to know is: WHY did we evolve this way? Is there some advantage to a family to be able to catch each other’s yawns?
(“The family that sleeps together keeps together?”
“The family that snores together does more together?”)
Most babies and toddlers won’t catch yawns at all. They start catching at around age 2, and by age 5 about half of kids catch ’em (like with grown-ups).
Why did we evolve THIS way? If there is some advantage to yawns catching in a family, why aren’t they contagious right from birth? Is it that, until toddlers start to be independent, their moms give them whatever advantage catching a yawn might provide?
(Or does something magical about a new baby’s biology try to protect it from catching EVERYTHING from the outside world: Nasty viruses and bacteria, and prions, and who knows what-all? “If babies caught yawns, they’d get germs and pri-ons (get it? pri-yawns?”) [Hey, it rhymes as good as rap does. It “crap-rhymes”.]
When the baby gets older, its body defenses loosen up, and those sneaky contagious yawns are able to get to work? Silly, but what if it were TRUE!
Even after toddler age, Asperger’s and autistic kids don’t catch yawns much, but if they’re told to focus more on people’s eyes, they do better because eyes are important in yawn-catching.
(In one study, two groups were shown a photo of the same yawning guy–one with his mouth blurred out, the other with his eyes blurred out. It’s interesting that the group that saw his yawning mouth did NOT start yawning. The group that saw no yawn at all–no mouth– but only the guy’s eyes DID start yawning.) Why is THAT?!
IF part of the function of yawning is to strengthen bonds between us, it makes sense that eye contact would be involved–doesn’t it?
(BTW, schizophrenics also catch yawns less than other people–and they catch less laughter, too, the poor things.)
Among most mammals, males yawn more, because yawning has links to testosterone production. In rats, most of the hormones that produce yawning and stretching also produce erections. (So THAT’s why you guys always fall asleep afterward!)(Let’s pause a moment in sympathy for the lowly researcher who got stuck with documenting ratty boners.)
“…humans may be unique in that both sexes yawn equally…” WHY?
(Ladies, are we just more BORED with our males?)
“Men–You boys are just so HOT you just wear us ladies out and make us TIRED!”
- “I have also noticed that under slight fear there is a strong tendency to yawn” (Darwin 1872:291).
- In primates, yawning appears in stress or conflict situations (Altmann 1967).
- Yawning is seen in uneasy or aggressive chimpanzees, gorillas, gibbons, baboons, rhesus monkeys, patas monkeys, and (rarely) vervet monkeys (Lawick-Goodall 1968).
Okay, so we get it, already. We yawn when we’re nervous. WHY??? Peeing (and worse) makes sense–let’s get ready for action–but yawning?
Yawn Rhymes With Bond…Sorta Kinda…
We now know yawning cools the brain. If an ice-pack is put on the forehead, yawns are suppressed. One theory is that this cooling effect reduces stress.
This still does not explain why we yawn–why we were evolved to yawn, or to have contagious yawning.
Most of the info in this post is courtesy of the book “curious behavior” (sic) by Robert R. Provine. Dr. Provine theorizes, partly because our yawns happen with many “states” (sexual arousal, waking up, and going to sleep) that yawning happens when we’re about to change from one “behavioral or physiological state” to another–that yawning helps us do this.
I’m going to modify the doctor’s theory:
“Yawning functions as a de-stressor and social bond-strengthener.
It cools the brain to a receptive or readiness state to prepare it for a change in focus by the mind or body, AND, through its contagious nature (the driving force of which is not yet known) it helps enlist the same state from nearby individuals.”
AFTER I wrote that, I found on the blog “Mind Hacks” a pertinent comment within a post. A dog owner and her spouse were advised to yawn in front of their nervous dogs to calm them. The strategy was successful:
The Dog Owner’s Comment on Mindhacks
Fake a yawn–
They’ll calm right down!
Trivia: The Yawning Cure
Around 80% of people paralyzed on one side of their body because of a stroke have that side move when they yawn. (Trippy, huh?)
Trivia: The Yawning Curse
Chroniclers of the late Middle Ages reported yawning and ejaculation as symptoms of the terminal stages of rabies.
2014-02-17–As usual, the first version of this post was one big yawn (tee-hee). Revised opening to make slightly less boring and changed “I” to correct “Me” in title ’cause never made the pun I intended with it.