Navarro noted that DeSantis often displayed signs of anger through his body language and refrained from smiling, whereas Mike Pence exhibited signs of poise and composure. Nikki Haley seemed ready for a fight, and Vivek Ramaswamy appeared natural on stage.
Overall, their demeanor was quite varied and undoubtedly provided insight into these candidates' capabilities under pressure.
From Politico:
As Trump’s closest rival, Florida Gov. Ron DeSantis spoke first. He was a little nervous, as to be expected from the opening candidate: His lips quivered. He also looked almost angry. His voice was forceful and lacked modulation, which made it hard for viewers to distinguish his most important points. And throughout most of the event, he failed to smile. That may not seem like much, but part of leading is showing all sides of your personality.
DeSantis has been criticized — even by his own party! — for being socially inept. But I did not see that. I saw a very serious candidate who is concerned about the issues; it’s clear from the tension in his face. His glabella (the space between your eyebrows) furrowed, which along with his emphatic hand gestures expressed his concern. DeSantis’ body language may not have communicated likeability, an important factor for undecided voters looking for a candidate they can trust, but he did show viewers that he considers the issues raised in the debate to be of the utmost importance.
Former biotech entrepreneur Vivek Ramaswamy consistently looked the most comfortable on stage, almost as if he was having fun. He smiled frequently and seemed to enjoy the audience’s chorus of cheers and boos.
His gestures were the broadest and the most emphatic of the pack. When you make broad gestures, you lend more power to your words than someone gesturing lightly or not at all. Ramaswamy also made repeated use of what’s called a precision grip — with his index finger and thumb making an OK sign — which people use to show that they have command of a topic.
His beaming smile garnered attention and defanged his detractors. But former South Carolina Gov. Nikki Haley turned that smile into what we call a grimace — teeth visible, high tension in the face — during one of their fiery interchanges. In part, that could be because Ramaswamy spread his arms so wide that he infringed on Haley’s space, a violation our brains interpret as threatening.
We encourage you to click the link above to the full article at Politico. It's a really interesting read, and definitely gives you some good insight on these GOP candidates.