I'm a body language expert. Here's what I noticed at the conventions.

When Nancy Pelosi is speaking, notice she arches her eyebrows. This is what I like to call “the human exclamation point.” It’s a gravity defying behavior: We only expend energy when we are passionate about something, and in this case, she’s describing how proud she is of the size of her caucus and how many women are in it. She wants the viewer to pay attention to her confidence, and by repeatedly arching her eyebrows, she says: Don’t just listen to my words, listen to my body language as well. She finishes her speech with a “steeple,” the finger points together, which is another sign of confidence.

Rep. Alexandria Ocasio-Cortez was only given a very short segment in the DNC, but when it came to her nonverbal presentation, she was very effective. Without listening to what she’s saying, you can see that she’s a good speaker. Unlike Biden, her eyes are wide open and relaxed. What this tells the viewer is that she is confident and comfortable with what she is saying, and that’s really important in public speaking. What we look for as viewers without even knowing we’re looking for it is whether the speaker makes us comfortable. That’s often conveyed through body language. Ocasio-Cortez is clearly adept with this medium, and it shows in her body language.

Most importantly, she’s not overly dramatic; she’s not raising her voice—and you can tell even without the sound. Her comfort here should make viewers comfortable—and perhaps opponents uncomfortable.