Reading other people's body language is tricky business.
If someone's crossing his arms, for example, you could assume that he's closed off, when in fact he's just cold.
That said, when you're trying to discern what a person is really thinking and feeling, it helps to know what kind of gestures and facial expressions to look for.
Because sometimes, a person's nonverbal displays don't quite match up with what she's telling you out loud.
Below, we've rounded up 19 scientific insights into the significance of body language, pulled from Psychology Today, research journals, and a few awesome books.
SEE ALSO: 8 body language tricks to instantly appear more confident
The shoulder shrug is a universal signal of not knowing what's going on
According to Barbara Pease and Allan Pease, authors of "The Definitive Book of Body Language," everybody does the shoulder shrug.
The shrug is a "good example of a universal gesture that is used to show that a person doesn't know or doesn't understand what you are saying," they write.
"It's a multiple gesture that has three main parts," they continue. "Exposed palms to show nothing is being concealed in the hands, hunched shoulders to protect the throat from attack, and raised brow, which is a universal, submissive greeting."
Open palms are an ancient display of honesty
When someone swears to tell the truth in a court of law, they put one hand on a religious text and raise their other hand into the air, palm facing whoever they're speaking to.
That's because, the Peases write in "The Definitive Book of Body Language," an open palm has been associated with "truth, honesty, allegiance, and submission" throughout Western history.
"Just as a dog will expose its throat to show submission or surrender to the victor," they write, "humans use their palms to show that they are unarmed and therefore not a threat."
A lack of crinkles around the eyes suggests a potentially fake smile
The jury is still out on whether we can tell when someone is faking what scientists call a Duchenne smile. It's the expression we make when we're genuinely experiencing positive emotion.
At one point, researchers believed that making a genuine smile was nearly impossible to do on command. The smile, they said, was all about the crow's-feet around your eyes. When you're smiling joyfully, they crinkle. When you're faking it, they don't.
If someone's trying to look happy but really isn't, you won't see the wrinkles.
More recently, a study from Northeastern University researchers found that people could do a pretty good job of faking a Duchenne smile, even when they weren't feeling especially happy.
It seems safe to say that if the crinkles aren't there, the person's probably not genuinely happy. But just because the crinkles are there doesn't necessarily mean they're elated.
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