I've recently become aware of this - I kinda knew I was always doing it, but just now it got me self conscious and thinking about it:

When crossing paths with a stranger, you are supposed to be friendly and smile at them, acknowledge them through a nod, and so on.

This is particularly the case in many service industries:

grocery stores - associates and customers acknowledging each other (not during checkout, but just walking around in the store)

fellow gym members as well as staff and members (again only walking around, not during particular business related interactions)

Another example might be you walk in a public bathroom and someone just comes out the door, you'll look each other briefly in the eyes, "smile", nod, acknowledge each other, and move on.

Now here's the thing I've become aware of, and mostly guys do this:

We don't actually smile.

In fact, we are kind of grumpy looking. Our mouth and eyebrows go into a frown, we press our lips together, and the only thing close to a smile that we do is to create a crease on the sides of our mouth.

Hard to explain... And hard to find actual pictures of this...


besides that he looks in the distance and he looks concerned, but imagine he looks at you and gives you a nod like that. pretty close!


he looks slightly more surprised, and worried, then what people usually look like, especially because the eyebrows are going up.


he's got too much "darnit!" on his face, and his eyes are sad looking, but again, the general idea comes across.


he has an actual upward curved smile going on, but definietly the lips pressed together like that

So again:

  • Mostly guys do it
  • it is done for acknlowledgement/politeness when you cross paths
  • it usually goes with a nod and brief eye contact, whereas the nod goes down
  • the eyebrows might seem kind of like a frown, since you're noding down, while looking upwards in the persons eyes
  • your lips are pressed together
  • often the mouth will actually go into a reverse smile curve (meaning frown)
  • the mouth gets kinda pulled to the sides, like we're making a wide mouth, just like when smiling.

First of all: Do you know what I'm talking about? Do you do it? Has it been done to you?

Does it have a proper name?

Why do we do it? Why don't we actually smile? We do we look rather grumpy when smiling like that?

I've noticed that we do a similar face in many different situations. Sometimes someone might tell you something that might make you smile or even laugh, but to them it's rather sincere, so you press your lips together, trying to make a frown, but you still can't help to smile a little. There are many expressions that this kind of face can express (as you can see in the pictures), they all have a certain subtle difference to them, and definitely very different meanings, but I feel as if the mouth pressed together and kinda mixing a grin with a frown remains constant. The particular facial expression I am talking about is also accompanied by a nod, making it distinct.

Why do we do this so often?

Are we hiding something? Is this some sort of a default expression?

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    $\begingroup$ This is interesting. I'm familiar with the distinction between authentic smiles (so-called Duchenne smiles) and inauthentic ones, in that the muscles around the eyes are only activated in the former kind. What you are talking about, though, seems more specific than that. I'm not sure I understand exactly what the phenomenon you're looking for is, but I think you might be over-generalizing a little. $\endgroup$
    – lea
    Commented Jul 14, 2014 at 7:31
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    $\begingroup$ @olli: Yes, I do it also, and then I say to myself "where did I pick this up from" ?! I started doing it when I entered "adulthood" after college when working in the corporate world. I think I just picked it up from others around me. Maybe it reflects all the stress of the modern days professional man in a complicated contradictory world? $\endgroup$ Commented Jul 14, 2014 at 20:44
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    $\begingroup$ Understanding why people move their body in certain controlled and uncontrolled ways formally defined as micro expressions is a worthless endeavor. For one must understand the current state of the stimulus to the brain and the internal programming which dictates how and why a person responds in such a way. Modern psychology does not answer those questions. $\endgroup$
    – user3832
    Commented Jul 16, 2014 at 15:06
  • $\begingroup$ And I thought Dr. Lightman was on to something... $\endgroup$ Commented Jul 17, 2014 at 18:14
  • $\begingroup$ FWIW I've seen plenty of women do this. Usually involving prior bad behavior toward them by some guy. $\endgroup$
    – Sixtyfive
    Commented Aug 6, 2019 at 8:06

3 Answers 3


Since this (excellent) question has been around for a while without any answer, I thought I'd give my two cents.

I think we do this as a gesture of respect to the other person. We may fear that if we don't acknowledge them at all, it will come off as rude or arrogant. Maybe we fear that if we don't even look at the other person, we're basically pretending as if they're not there. So we want to acknowledge them in some way. However, they are often a total stranger, so we may feel that saying "hi" or anything like that, is a bit over the top. (Sometimes we may actually say "hi" combined with the frown, though.)

So, as you suggest in the question itself, it's a way to acknowledge the other person.

Now, why not give an authentic smile? Well, because it's a little bit difficult to give a real smile without actually being happy about something. If you see a dear friend for the first time in months, you'll probably give a real smile, because you are genuinely happy to see them. When you meet a total stranger, the truth is that that person doesn't really mean much to you. You might not really feel that you have anything to smile about.

Have you ever tried to smile for a photograph, when you're actually not very happy? It's not easy. The smile often looks inauthentic. Similarly here, we try our best to greet the passing person with respect, but it's not that easy to smile authentically.

Not wanting to look like a fake smiling clown, we may not even try that hard. The other person knows that we're just trying to acknowledge them. They're not looking to give us an Oscar award anyway. And we know that they know that.

If we were to make eye contact with them without altering our facial expression at all, we might end up looking a bit mad. (Imagine it, you cross paths with someone, and they just look into your eyes without altering their facial expression at all. Personally, I would be a bit freaked out if that happened.) Most changes in our expression will be better than nothing (except, of course for a downright hostile or angry face). It means we acknowledge that they are there, and we are making an effort to do so.

There's another possible reason: Fear of rejection. We want to acknowledge the person. So why not give them a real smile? Well, what if you do, and they respond with a careful nod, a frown like the ones in OP, or even totally ignore you? (This is quite possible, since it's not that easy to produce a genuine smile.) When you genuinely smile at someone, you are giving a little part of yourself out to them. If they then merely nod at you, or something like that, most people will feel uncomfortable. As if they just gave someone a gift and the other person was uninterested in the gift. I'm not saying this is a reasonable feeling, I'm just saying it's the way people might feel, thus motivating their behavior.

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    $\begingroup$ Nailed it! Sounds plausible to me. Maybe add a little bit of "I have nothing to smile about right now anyway" and I think thats it! $\endgroup$ Commented May 21, 2016 at 14:49
  • $\begingroup$ @olli I'm glad you liked it :) $\endgroup$
    – Fiksdal
    Commented May 21, 2016 at 15:01
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    $\begingroup$ This post does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. $\endgroup$
    – Arnon Weinberg
    Commented Dec 30, 2017 at 8:28

I suspect that it's rooted in primal responses to seeing a human being you are not expecting to see. This would in part explain the gender difference.

If you've ever seen two cats unexpectantly try to walk past each other, you'll get the problem here: what if the 'unexpected other' perceives you as a threat and attacks you in self defence. For this reason, cats freeze, careful to to pass until they've asserted their dominance, say by arching their back to look bigger (because there is a decent chance they will be attacked).

With humans, we're social creatures. So we use our advanced social nature to communicate we are friendly. For this reason, women/some men give a nice smile, with warm bright eyes. This says 'I come in peace'.

But men might still have a primal need to show he's not a threat, but also suggest willingness to fight back if attacked. Let's look at the thrown/smile for clues of this:

-lips tightly pressed together. This indicates a strong desire to not show teeth. Showing teeth can be interpreted as aggressive. -frowning is an assertive sign of discomfort. Not passive. -shoulders tense up a little and head is loweres, making the shoulder area look bigger and stronger. -eye contact is less direct than the 'female' version. Avoiding being aggressive.

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    $\begingroup$ Welcome. Please add credible sources and preferably references to scientific journal papers to your answer. It may as well be your personal opinion as of now. $\endgroup$
    – AliceD
    Commented Dec 27, 2017 at 10:30

Why do we do this so often? Are we hiding something? Is this some sort of a default expression?

It's a psychological defense mechanism involving the conflict between the true feelings of the authentic self and the persona we believe protects ourselves or others from harm or pain. There are two opposing basic scenarios for this phenomenon:

  1. The authentic self would naturally like to smile warmly and show true friendliness toward the person they encounter, but not knowing the person well, is afraid to either:

a) encourage too much social intimacy, too soon (i.e. appear overly friendly); or b) unwittingly provoke anger or some other irrational behavior in some potentially unhinged individual; or c) both.

  1. The authentic self really does not want to smile at all (is very sad about something, or doesn't really like the person they encounter), but makes a feeble attempt anyway, for the purpose of covering up 'negative' feelings because:

a) they don't want to negatively affect the other person; or b) they don't want to talk about personal matters; or c) they don't want to appear rude; or d) any combination of the above.

As implied in my opening paragraph, the persona is attempting to set or adjust physical, emotional, and/or psychological boundaries.

Also the author of the question is quite right in suggesting that this type of defense mechanism generally works differently in men and women; because, many women tend to set boundaries for all of the above reasons, and then some.

So to answer the germane questions:

  • It occurs more frequently in metropolitan areas, where we are more likely to encounter people we don't know very well.
  • Yes, we are hiding something, but in this case for valid reasons.
  • It can be characterized as a sort of "default expression", and that's a good way to describe it.
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    $\begingroup$ This post does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. $\endgroup$
    – Arnon Weinberg
    Commented Dec 30, 2017 at 8:27

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