Real smiles crinkle the eyes. 

When it comes to smiling, the mouth can lie but the eyes can’t. Genuine smiles reach the eyes, crinkling the skin to create crow’s feet around them. People often smile to hide what they’re really thinking and feeling, so the next time you want to know if someone’s smile is genuine, look for crinkles at the corners of their eyes. If they aren’t there, that smile is hiding something.

Copying your body language is a good thing. 

Have you ever been in a meeting with someone and noticed that every time you cross or uncross your legs, they do the same? Or perhaps they lean their head the same way as yours when you’re talking? That’s actually a good sign. Mirroring body language is something we do unconsciously when we feel a bond with the other person. It’s a sign that the conversation is going well and that the other party is receptive to your message. This knowledge can be especially useful when you’re negotiating, because it shows you what the other person is really thinking about the deal.

Posture tells the story. 

Have you ever seen a person walk into a room, and immediately, you have known that they were the one in charge? That effect is largely about body language, and often includes an erect posture, gestures made with the palms facing down, and open and expansive gestures in general. The brain is hardwired to equate power with the amount of space people take up. Standing up straight with your shoulders back is a power position; it appears to maximize the amount of space you fill. Slouching, on the other hand, is the result of collapsing your form; it appears to take up less space and projects less power. Maintaining good posture commands respect and promotes engagement, whether you’re a leader or not.

Bad body language tells us a lot too.

Eyes that lie. Most of us probably grew up hearing, “Look me in the eye when you talk to me!” Our parents were operating under the assumption that it’s tough to hold someone’s gaze when you’re lying to them, and they were right to an extent. But that’s such common knowledge that people will often deliberately hold eye contact in an attempt to cover up the fact that they’re lying. The problem is that most of them overcompensate and hold eye contact to the point that it feels uncomfortable. On average, Americans hold eye contact for seven to ten seconds, longer when we’re listening than when we’re talking. If you’re talking with someone whose stare is making you squirm—especially if they’re very still and unblinking—something is up and they might be lying you.

Raised eyebrows signal discomfort. There are three main emotions that make your eyebrows go up: surprise, worry, and fear. Try raising your eyebrows when you’re having a relaxed casual conversation with a friend. It’s hard to do, isn’t it? If somebody who is talking to you raises their eyebrows and the topic isn’t one that would logically cause surprise, worry, or fear, there is something else going on.

Exaggerated nodding signals anxiety about approval. When you’re telling someone something and they nod excessively, this means that they are worried about what you think of them or that you doubt their ability to follow your instructions.