From my textbook I had as a student teacher taking my teaching mathematics course:
“Ms. Spencer’s body language suggests that she doesn’t take what she’s saying seriously enough to face her listeners. Ms. Castillo’s body language clearly tells her students, ‘I’m talking to you and I expect you to be listening to this important message!'”
“Managing to focus your eyes on each student regularly during the course of classroom activities, and occasionally making positive expressions and gestures (a smile, a wink, a thumbs up) when you’ve caught the student’s eye, helps establish an atmosphere of mutual respect.”
I don’t know. I think Ms. Spencer’s body language suggests she is asking “You think you’re better than me?!” I think Ms. Castillo is saying “It’s go time!” Am I the only one who wants to shout “Mandelbaum! Mandelbaum! Mandelbaum!”? Ms. Castillo may have an important message. Her students may also have something important to say. Maybe this wasn’t an important point to make back in ’96.
Not sure I’d recommend winking at students who’ve caught your eye.
Maybe Sal Khan is on to something when he says “the face is hugely distracting”. I know mine is.
Chris Hunter 
Ms. Castillo is trying too hard. She is dying for me to pay attention, which perhaps suggests that she doesn’t believe her message strongly enough. Ms. Spencer is upset with me. I probably deserve it, though.
Truly, this is silliness of the first order masquerading as authoritative resource. Thanks for sharing.