Why do Human beings smile?
After all, every other animal bares its teeth in threat or fear. Not us. We’re…friendly? 
Why?
I had an English professor (I only mention this so that you can take his qualifications into consideration) that claimed it was a way of saying, “See, I’ve got the teeth, but I’m not going to use them on you. I’m nice.”
Personally, I’m still not all that confident in his explanation’s accuracy. :dubious:
From this article:
Any answer to this question has to take into account that some smiles show teeth and some don’t.
Humans can’t be the only animals that smile. I could swear I’ve seen cats with smiles of contentment and dogs with big goofy grins on their faces.
I don’t have a scientific source, but I was going to post a guess like Dignan’s. I think that makes a lot of sense, and I don’t think smiling is unique to humans. I’m willing to bet that if NO other animals do it (which I doubt), at least the higher apes would have a similar gesture.
Makes sense to me, Everton. After all, we also smile and laugh out of nervousness at times. Heh-heh. heh. heh…
Ah, but what about babies? They have no teeth. And yet, the smile is the one of the first acts of communication. (Any parent knows that “the cry” is the first.)
Short answer to the OP: we don’t know. We really don’t know. There are certainly theories out there, but we don’t know.
Evolutionary theory says that one reason babies smile is to evoke positive emotions in their caretaker. Human infants are helpless at birth, so the better the caretaker feels about the baby, the better it is for the baby’s continuing existence.
As to why we actually “smile”, I can’t find any cites. The stuff I came across was related to what everton posted, but it still doesnt explain the reason for the physical manifestation. It’s anybody’s guess why we depict happiness by pulling our lips upwards instead of, say, poking a finger at our tummies, or something else.
I can’t say anything definitive, John, but I think they’d have the instinct even if they didn’t have the actual teeth. You don’t learn to smile, it’s instinctive when you want to show pleasure or whatever - so having or not having teeth shouldn’t matter.
Humans are definately not the only animals that smile. When we get home and the dog is really excited to see us, she’ll give us a huge smile, teeth bared and all I (and no, this is not a threatening teeth-baring).
Humans are definately not the only animals that smile. When we get home and the dog is really excited to see us, she’ll give us a huge smile, teeth bared and all (and no, this is not a threatening teeth-baring).
“Evolutionary theory” says no such thing. It may be conjectured that that is the reason, and that reason may be a consequence of our evolutionary history. But since many animals (and not just mammals) take care of their young, even without the benefit of lips (e.g., birds), much less smiles, I’d think this is a rather ad hoc explanation.
we smile coz we are happy 
no teeth in that smiley.
I like everton’s reply.
It makes sense that smiling would evolve from the fear expression. (And people who are nervous do have a sort of smile.) By smiling when seeing someone, you are saying: “Hey I’m no threat to you! See I’m afraid”
Smiling is almost certainly a fear/submissive display, especially in babies.
In older individuals it is probably a kind of social reinforcement and bonding.
…and a thank you to Nat King Cole…
Smile
(Charles Chaplin, John Turner, Geoffrey Parsons)
Smile, tho’ your heart is aching,
Smile, even tho’ it’s breaking
When there are clouds in the sky,
You’ll get by
If you smile
Through your fear and sorrow
Smile ~ and maybe tomorrow
You’ll see the sun come shining through
For you.
Light up your face with gladness,
Hide every trace of sadness.
Although a tear
May be ever so near
That’s the time you must keep on trying,
Smile ~ what’s the use of crying?
You’ll find that life is still worthwhile
If you’ll just smile.
~interlude~
That’s the time you must keep on trying
Smile ~ what’s the use of crying?
You’ll find that life is still worthwhile
If you’ll just smile.
Most babies smile because they are laughing and having fun, or because they see their mother cooing at them lovingly.
I’m guessing that you not only have no children of your own, but spend very little time around them. Which is to say, I think your hypothesis is flawed.
A related question: why do we laugh?
V.S. Ramachandran, a cognitive neuroscientist, has offered some speculation: the smile is an “aborted grimace”. Laughter often occurs when a potentially threatening situation is suddenly revealed to be harmless–the built up tension (whether muscular or the neurological equivalent) can then be suddenly released in explosive peals of breath. The vocal aspect, moreover, signals others that the potential threat has turned out to be harmless. A smile, similarly, may have begun its life as an intimidating “grimace”; when a friendly face is recognized, it is easily and suddenly transformed to a smile.
This is all paraphrased (and from memory) from “Phantoms in the Brain”, a decent read. Most of the book is of top-notch interest level, although personally I found this smile-laughter conjectural explanation pretty thin (which is perhaps why I remembered it).
I seem to recall reading that even babies born blind smile. I don’t believe it’s a learned behavior.
And my dog also smiles when he’s happy to see me; it’s a breed trait, and I assume it to be an appeasing smile as stated above. He pulls up just the front part of his upper lip, unlike a snarl where he draws both lips back.
My dog (a standard poodle) smiles too. I’ve heard that it’s not actually a canine trait, but an imitation of humans. I’m not really sure how true that is, though. Her mother smiles too, so it could be genetic, or maybe learned from the parents.