“Break through” was his favorite instruction….Another thing he taught me was not to nod my head when I was acting. This infuriated him. “Remember to be definite,” he said, “moving your head is indefinite. Only make a move when it means something.” (Dawn Addams,”Films & Filming, 1957)
One of the very first lessons young Charlie learned half a century earlier from his mentor H.A. Saintsbury was not to move his head too much while acting.