This isn't quite new news. They've been doing a few studies here and there on gesticulation for things like presentations and verbal communication skills, but these are usually external studies on communication not relating to internal processing. It doesn't surprise me that it might help cognition. I do all sorts of little hand motions and gestures when I am thinking (if I can't pace, I write in my head as I walk). Some children do these sorts of things all the time and good educators have sort of learned to tell the difference between kids' learning habits and annoying kid habits. This sort of thing would help more I imagine.
At the very least it gives me some excuse for using various finger tapping motions that appear outwardly diabolical. I can just say I'm calculating...which is perhaps true anyway...
21 minutes ago