# Why Do Human Beings Smile? **URL:** \ **Category:** Factual Questions\ **Created:** [April 30, 2003, 1:52pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146 "2003-04-30T13:52:36Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [April 30, 2003, 1:52pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/1 "2003-04-30T13:52:36Z")
Why do Human beings smile? After all, every other animal bares its teeth in threat or fear. Not us. We’re…_friendly_? 😕 😕 Why? ---
**Author:** ![Dignan](https://avatars.discourse-cdn.com/v4/letter/d/f07891/32.png) [@Dignan](https://boards.straightdope.com/u/Dignan)\ **Post date:** [April 30, 2003, 1:56pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/2 "2003-04-30T13:56:22Z")
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: ---
**Author:** ![everton](https://avatars.discourse-cdn.com/v4/letter/e/ecb155/32.png) [@everton](https://boards.straightdope.com/u/everton)\ **Post date:** [April 30, 2003, 2:01pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/3 "2003-04-30T14:01:36Z")
From [this article](http://www.emory.edu/LIVING_LINKS/i/people/cohen_essay.html): > [@](#): > > …the human smile could be related to the primate “silent bared teeth display” (SBT) and that the laugh is the human form of the “relaxed open mouth display” (ROM) in chimpanzees. These similarities held true across morphological structure and function. > > **For instance, the SBT is used by many primates to indicate fear and anxiety but is used by chimps in an appeasing context as well**. Although we may not realize it at first, humans also use the smile as an appeasing expression. When we meet someone for the first time or bump into someone we know, and smile, it is an indication of peace or lack of hostility. And have you ever seen someone wearing a nervous grin? In moments of tension or even sadness, many people smile, as if to hide their true feelings inside. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [April 30, 2003, 2:16pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/4 "2003-04-30T14:16:48Z")
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. ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [April 30, 2003, 3:48pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/5 "2003-04-30T15:48:51Z")
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. ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [April 30, 2003, 3:51pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/6 "2003-04-30T15:51:03Z")
Makes sense to me, Everton. After all, we also smile and laugh out of nervousness at times. Heh-heh. heh. heh… ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [April 30, 2003, 4:30pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/7 "2003-04-30T16:30:45Z")
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. ---
**Author:** ![Aankh](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@Aankh](https://boards.straightdope.com/u/Aankh)\ **Post date:** [April 30, 2003, 4:42pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/8 "2003-04-30T16:42:16Z")
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. ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [April 30, 2003, 5:23pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/9 "2003-04-30T17:23:44Z")
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. ---
**Author:** ![monica](https://avatars.discourse-cdn.com/v4/letter/m/a183cd/32.png) [@monica](https://boards.straightdope.com/u/monica)\ **Post date:** [April 30, 2003, 8:17pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/10 "2003-04-30T20:17:20Z")
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). ---
**Author:** ![monica](https://avatars.discourse-cdn.com/v4/letter/m/a183cd/32.png) [@monica](https://boards.straightdope.com/u/monica)\ **Post date:** [April 30, 2003, 8:17pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/11 "2003-04-30T20:17:27Z")
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). ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [April 30, 2003, 8:27pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/12 "2003-04-30T20:27:55Z")
> [@](#): > > \*Originally posted by aasna \* > \*\*Evolutionary theory says that one reason babies smile is to evoke positive emotions in their caretaker. \*\* “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. ---
**Author:** ![Pavlos](https://avatars.discourse-cdn.com/v4/letter/p/ac8455/32.png) [@Pavlos](https://boards.straightdope.com/u/Pavlos)\ **Post date:** [April 30, 2003, 8:32pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/13 "2003-04-30T20:32:36Z")
we smile coz we are happy 🙂 no teeth in that smiley. ---
**Author:** ![zimaane](https://avatars.discourse-cdn.com/v4/letter/z/a3d4f5/32.png) [@zimaane](https://boards.straightdope.com/u/zimaane)\ **Post date:** [April 30, 2003, 8:53pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/14 "2003-04-30T20:53:13Z")
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” ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [May 1, 2003, 12:05am UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/15 "2003-05-01T00:05:48Z")
Smiling is almost certainly a fear/submissive display, especially in babies. In older individuals it is probably a kind of social reinforcement and bonding. ---
**Author:** ![ltfire](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@ltfire](https://boards.straightdope.com/u/ltfire)\ **Post date:** [May 1, 2003, 12:50am UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/16 "2003-05-01T00:50:58Z")
…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. ---
**Author:** ![FranticMad](https://avatars.discourse-cdn.com/v4/letter/f/c68b51/32.png) [@FranticMad](https://boards.straightdope.com/u/FranticMad)\ **Post date:** [May 1, 2003, 1:13am UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/17 "2003-05-01T01:13:52Z")
> [@](#): > > \*Originally posted by eburacum45 \* > **Smiling is almost certainly a fear/submissive display, especially in babies.** 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. ---
**Author:** ![Don\_Roberto](https://avatars.discourse-cdn.com/v4/letter/d/e47774/32.png) [@Don\_Roberto](https://boards.straightdope.com/u/Don_Roberto)\ **Post date:** [May 1, 2003, 1:49am UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/18 "2003-05-01T01:49:09Z")
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). ---
**Author:** ![Sister\_Vigilante](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@Sister\_Vigilante](https://boards.straightdope.com/u/Sister_Vigilante)\ **Post date:** [May 1, 2003, 5:29pm UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/19 "2003-05-01T17:29:18Z")
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. ---
**Author:** ![Already\_in\_Use](https://avatars.discourse-cdn.com/v4/letter/a/a9adbd/32.png) [@Already\_in\_Use](https://boards.straightdope.com/u/Already_in_Use)\ **Post date:** [May 2, 2003, 6:51am UTC](https://boards.straightdope.com/t/why-do-human-beings-smile/172146/20 "2003-05-02T06:51:27Z")
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.