Most everyone has been in a situation where the person you're dating, or interviewing, or arguing with makes a comment and something just feels ... off.
Perhaps it's less about what they said explicitly and more about how they looked while they said it. As in, their gaze was freakishly fixed on your face or their left leg kept jiggling.
Scientists have spent decades trying to figure out what these nonverbal displays really mean.
And while sometimes they mean absolutely nothing, in other cases they can reveal a lot about what the person is thinking or feeling. Maybe they're super nervous, or maybe they're trying to trick you.
Below, we've rounded up 18 of the most useful scientific insights into the significance of body language, pulled from Psychology Today, research journals, and a few awesome books.
Keep in mind that context is really important — for example, you can interpret crossed arms to mean that someone's closed off, or that they're cold. Use your own judgment.
This is an update of an article originally posted by Drake Baer and Max Nisen.
The shoulder shrug is a universal signal of not knowing what's going on
Ever notice how 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."
If their voice goes up or down, they're likely interested
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 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.
Raised eyebrows are often a sign of discomfort
If someone is closing their palm and pointing with their index finger, then they're trying to display dominance, though it doesn't always work out.
"The Palm-Closed-Finger-Pointed is a fist where the pointed finger is used like a symbolic club with which the speaker figuratively beats his listeners into submission," the Peases write. "Subconsciously, it evokes negative feelings in others because it precedes a right overarm blow, a primal move most primates use in a physical attack."
If they mirror your body language, the conversation is probably going well
In an attempt to avoid looking shifty-eyed, some liars will purposefully hold their gaze a touch too long, so that it's slightly uncomfortable, according to behavioral analyst and body language expert Lillian Glass.
They may also stand very still and not blink.
Eye contact shows interest — both positive and negative
How people hold themselves is a big clue to how they're feeling.
If someone's leaning back and relaxed, they probably feel powerful and in control. In fact, research has found that even people born blind raise their arms in a V shape and lift their chins slightly when they win a physical competition.
On the other hand, a low-power pose — seen when someone closes up and wraps their arms around themselves — increases cortisol, a stress hormone.
Interestingly, Harvard professor Amy Cuddy and colleagues have found that the relationship works the other way, too. Striking a "power pose" can make you feel more confident in the moment.
A 'cluster' of gestures shows a real feeling of connection
Out of 2,000 negotiations videotaped by Gerard I. Nierenberg and Henry H. Calero, the authors of "How to Read a Person Like a Book," there wasn't a single settlement when one of the negotiators had their legs crossed.
"Psychologically, crossed legs signal that a person is mentally, emotionally, and physically closed off," writes psychologist Travis Bradberry — which may mean they're less likely to budge in a negotiation.
A clenched jaw, tightened neck, or furrowed brow shows stress
Navarro told Business Insider that we've evolved to display nervousness without using any words.
Some of the most common manifestations of our anxiety? Touching your face and rubbing the skin on your hands. Both can be soothing behaviors when you're feeling uncomfortable.
"It's hilarious how often we touch ourselves under stress," Navarro said.
If they're laughing with you, they're probably into you
Whether they're innate or learned, there are a number of signals and behaviors people use when they feel that they're a leader, or at least are trying to convince you that they are.
They include holding an erect posture, walking purposefully, steepling and palm-down hand gestures, and generally open and expansive body postures.
A shaking leg signals a shaky inner state
Riggio's research suggests that there's a specific type of smile people display when they're trying to act seductive.
He writes in Psychology Today:
"[T]hey typically display positive affect — a slight smile that accompanies direct eye contact, with a slow glance away, but still holding the smile.
"Interestingly, the seductive smile could be accompanied by submissive behavior (tilting the head downward), or dominant behavior — proudly and slowly glancing away."
Read the original article on Tech Insider. Copyright 2016.