As far as I know, the way people of Elinor & Willoughby's class held themselves, the posture of their bodies, I mean, was much straighter than the way most of us do now. They bowed and curtsied to one another; shaking hands was still quite "modern". Although clothes had loosened up a bit in the previous decade or so, women did wear corsets, and the sort of "stocks" and collars men wore under theri chins did the same thing: people kept their backs straight, their heads up, didn't lean against the backs of their chairs, etc.